Article

Safety effects of permanent running lights for bicycles: A controlled experiment

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Abstract

Making the use of daytime running lights mandatory for motor vehicles is generally documented to have had a positive impact upon traffic safety. Improving traffic safety for bicyclists is a focal point in the road traffic safety work in Denmark. In 2004 and 2005 a controlled experiment including 3845 cyclists was carried out in Odense, Denmark in order to examine, if permanent running lights mounted to bicycles would improve traffic safety for cyclists. The permanent running lights were mounted to 1845 bicycles and the accident rate was recorded through 12 months for this treatment group and 2000 other bicyclists, the latter serving as a control group without bicycle running lights. The safety effect of the running lights is analysed by comparing incidence rates - number of bicycle accidents recorded per man-month - for the treatment group and the control group. The incidence rate, including all recorded bicycle accidents with personal injury to the participating cyclist, is 19% lower for cyclists with permanent running lights mounted; indicating that the permanent bicycle running light significantly improves traffic safety for cyclists. The study shows that use of permanent bicycle running lights reduces the occurrence of multiparty accidents involving cyclists significantly. In the study the bicycle accidents were recorded trough self-reporting on the Internet. Possible shortcomings and problems related to this accident recording are discussed and analysed.

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... Several studies have assessed the effect of conspicuity aids for cyclists on the accident rate (AR) (Chen and Shen, 2016;Hagel et al., 2014;Heesch et al., 2011;Hoffmann et al., 2010;Lacherez et al., 2013;Madsen et al., 2013;Miller, 2012;Teschke et al., 2012;Thornley et al., 2008;Tin Tin et al., 2014Wood et al., 2009). Most of these studies found no significant results and were not RCT studies. ...
... Most of these studies found no significant results and were not RCT studies. Madsen et al. (2013), however, conducted an RCT to assess the effect of running lights for cyclists and used self-reported accidents to estimate the effect. They found that the number of accidents decreased by 61%. ...
... Therefore, any difference between the test and control groups indicates a potential reporting bias between the groups, which may occur because the study is non-blinded, and the participants know whether they belong to the test or control group. We adjusted for potential report bias as suggested by Madsen et al. (2013) by correcting the risk of multiparty PIAs in the control group, using a correction factor equal to the estimated ARR for single PIAs as a general correctional factor ...
Article
This study is the first randomised controlled trial (RCT) of the safety effect of high-visibility bicycle clothing. The hypothesis was that the number of cyclist accidents can be reduced by increasing the visibility of the cyclists. The study design was an RCT with 6793 volunteer cyclists - 3402 test cyclists (with a yellow jacket) and 3391 control cyclists (without the jacket). The safety effect of the jacket was analysed by comparing the number of self-reported accidents for the two groups. The accident rate (AR) (accidents per person month) for personal injury accidents (PIAs) for the test group was 47% lower than that of the control group. For accidents involving cyclists and motor vehicles, it was 55% lower. The study was non-blinded, and the number of reported single accidents was significantly lower in the test group than in the control group. This is likely a result of a response bias, since the bicycle jacket was not expected to affect the number of single accidents. To compensate for this bias, a separate analysis was carried out. This analysis reduced the effect of the jacket from 47% to 38%.
... Reflectors attached to knees and ankles, which produce biomotion, would help to increase the detection and recognition distance at night. Another evidence showed that the permanent running lights mounted to bicycles would improve the detection distance [32]. However, detection distance will vary depending on the visible area of an object, and the visible area of reflective tape, seen by a driver behind the bicycle, is much smaller than the visible area of reflective clothes. ...
... Biomotion constitutes an effective measure with adequate consideration of road users when the bicycle is a running condition, specially since wearing reflectors at the knees and the ankles is not always possible for all bicyclists. However, the use of reflectors and a permanent running light have reduced multiparty bicycle accidents with personal injury [17,32]. For that reason, the main focus is on the simple treatment in which the color modified of the tires of bicycle may emphasize the visibility, conspicuity and signal of presence of bicycle in all lighting conditions. ...
Article
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Poor sensory conspicuity and poor visibility of bicycles are key factors that correlate strongly with bicycle-vehicle accidents. Although researchers have explored how to improve detection distances, i.e., the distances from which bicycles can be recognized by other road users, there is a dearth of research on ways to signal bicyclists' presence on the road. This study investigates how to enhance, at minimum cost, the level of visibility and sensory conspicuity of bicycles; it also considers ways to signal their presence to other road users, without necessitating any active behavior by bicyclists themselves. In the first study, the level of visibility of 6 rear-end components of bicycles was analyzed according to Adrian's model; the sensory conspicuity of these same components was analyzed via respondent perceptions in conditions of sunlight, twilight with no car headlights, twilight with car headlights, and night with car headlights. The level of visibility and sensory conspicuity of the 6 rear-end components were compared with considering angular size of the components under 4 lighting conditions. The level of visibility of the rear fender was good under sunlight and night-time conditions; in other conditions, the level of visibility was directly affected by painting the fender a silver color with reflectivity and also by the fender's angular size. However, the rear tire, among the 6 components tested, had a higher visible area when used with a short fender; it also produced rotational effects during riding conditions with no extra effort by the cyclists. In the second study, adhesive tape with specific patterns and 6 different color combinations were applied to the rear tire of a bicycle under the same lighting conditions, with the aim of creating a strong signal of the bicycle's presence for other road users. Among the 6 combinations, white stripes overlaid on the color red provide an optimal combination in terms of detection distance. The mean detection distance of white stripes on red in sunlight was 138.67 m, 94.67 m in twilight without car headlights, 94 m in twilight with car headlights, and 53.67 m at night with car headlights. In addition, this combination strongly signals the presence of the bicycle to other road users with no extra effort by the cyclists, thereby reducing the likelihood of drivers looking but failing to see bicycles. In sum, the study recommends that bicyclists install white stripes overlaid on red, in order to increase visibility and conspicuity and signal the presence of their bicycles, thereby reducing the likelihood of cyclist-vehicle collisions.
... During the day, wearing fluorescent red, yellow, and orange, as well as nonfluorescent yellow, increased driver detection distances for pedestrians and cyclists, as did wearing white on the upper body (Hagel et al., 2014;Kwan & Mapstone, 2009). Also, when crash rates were compared across one group of cyclists using daytime running lights versus a group not using lights, daytime crash rates were 33% lower for the former group, and rates for crashes producing injuries were 41% lower for those using the running lights (Madsen et al., 2013). ...
... Active systems also had longer detection distances during the daytime, but the differences were not statistically significant. These results are also supported by existing work that showed that daytime running lights significantly increase bicycle visibility (Madsen et al., 2013). ...
Technical Report
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Cyclist deaths are overrepresented among traffic fatalities, and increasing cyclist conspicuity to drivers could potentially reduce cyclist deaths, particularly at night. This report describes an experiment with various commercially available bicycle visibility-enhancement systems in terms of their conspicuity to drivers during the day and at night. Visibility enhancements included a headlamp, tail lamp, spoke lights, and retroreflective clothing, including garments that highlight biomotion. The results indicate that active visibility treatments, such as bicycle-mounted lights, make cyclists more conspicuous than passive systems like retroreflective vests and biomotion bands. Flashing headlamps and tail lamps were the most conspicuous treatments during both the day and at night; fast flashing headlamps (6.7 Hz) had higher detection distances and rates during the day, and moderately fast flashing headlamps (3.4 Hz) had higher detection distances and rates at night. Spoke lights and flashing tail lamps, along with retroreflective vests, also aided cyclist visibility during the day and at night, especially for vehicles approaching intersecting cyclists. Passive retroreflective visibility treatments were most effective at night, when the vehicle was passing the cyclist from behind. However, that approach also used reflectors, so the discrete effect of passive retroreflective treatments could not be determined. This study also found that biomotion markers alone do not significantly increase cyclist conspicuity in visually complex natural environments. For most approaches, flashing lights had greater detection distances than biomotion markers, which in turn had higher detection rates than headlamps and tail lamps.
... Bicycle lights are meant to make cyclists more conspicuous in the dark and thereby reduce collisions in darkness (Kwan & Mapstone, 2006). Bicycle lights may also affect collisions in daylight (Madsen, Andersen, & Lahrmann, 2013). In the present study, bicycle light use refers only to use of bicycle lights when cycling in the dark. ...
... Results from other studies of the effects of bicycle lights on crash involvement are highly inconsistent and partly counterintuitive. For example, a Danish experimental study found large (but non-significant) crash reducing effects of bicycle lights both in daylight (À18%) and in twilight (À51%), but not in darkness (Madsen et al., 2013). Martínez-Ruiz, Lardelli-Claret, Jiménez-Mejías, Amezcua-Prieto, Jiménez-Moleón, and Luna del Castillo (2013) found a large reduction of collisions, and a non-significant increase of single bicycle crashes among cyclists using lights. ...
Article
The present study has investigated relationships between cyclists’ safety equipment use, crash involvement, and other safety relevant behavior. The main focus is on relationships that indicate either behavioral adaptation (safety equipment use leads to riskier behavior) or precautionary behavior (safety equipment is used for cycling in risky situations). Three consecutive surveys were conducted in 2015, 2016, and 2017 years among 650 Norwegian cyclists. Most items were dichotomized and analyzed with logistic regression models. In contrast to the behavioral adaptation hypothesis, regular use of safety equipment (bicycle lights, high-visibility clothing, and helmets) was found to be negatively related to some types of high-risk behavior (listening to music and taking chances while cycling). Regular use of bicycle lights and high-visibility clothing is also negatively related to collision involvement. Safety equipment use was found to be positively related to regular winter cycling and cycling in mixed traffic (not on sidewalks), and it is most likely used as a precautionary measure in such situations. Some cyclists learn from crash involvement by starting to use safety equipment after a crash, but the results do not indicate that crash involvement deters from cycling. The main conclusion from the study is that recommending, promoting or even mandating safety equipment for cyclists can be expected to improve safety and that behavioral adaptation is not likely to occur, at least not to an extent that will outweigh the positive safety effects. The results do not support reservations against the use of “sporty” (well-equipped) models in campaigns for promoting cycling.
... In this paper we will report the results from two Danish studies with the goal to improve cyclists' visibility in order to investigate the safety effect of different types of visibility measures. In one study it was tested whether permanent running lights on bicycles improve cyclist safety (Madsen et al., 2013). In the second study, the safety effect of a yellow bicycle jacket was studied (Lahrmann et al., 2015). ...
... Upon sign up, the participants gave their informed consent to use the collected data for research purposes and use them in combination with other registers. In Madsen et al. (2013) and Lahrmann et al. (2015) the recruitment and selection is described in detail. ...
Article
Full-text available
A large number of studies show that high visibility in traffic is important in the struggle of getting the attention from other road users and thus an important safety factor. Cyclists have a much higher risk of being killed or injured in a traffic accident than car drivers so for them high visibility is particularly important. A number of studies have examined the effect of high visibility, such as reflective clothing, but most studies have been primitive, the data limited and the results very uncertain.
... Several previous studies have been conducted to analyze different aspects of cycling safety, such as crash frequency (Siddiqui, Abdel-Aty, & Choi, 2012;Kaplan & Giacomo Prato, 2015;Amoh-Gyimah, Saberi, & Sarvi, 2016), injury severity (Johnson et al., 2010;Juhra et al., 2012;Washington, Haworth, & Schramm, 2012;Kaplan, Janstrup, & Prato, 2017;Zhao, Carstensen, Nielsen, & Olafsson, 2018;Katanalp & Eren, 2020), cyclist behavior (Useche, Montoro, Alonso, & Oviedo-Trespalacios, 2018;Kaplan, Luria, & Prato, 2019;Poulos et al., 2019;Useche, Alonso, Montoro, & Esteban, 2019), or the safety effectiveness of cycling facilities or specific treatments (Jensen, 2008;Dill, Monsere, & Mcneil, 2012;Goodno, Mcneil, Parks, & Dock, 2013;Madsen, Andersen, & Lahrmann, 2013;Pulugurtha & Thakur, 2015;Digioia, Watkins, Xu, Rodgers, & Guensler, 2017;Madsen & Lahrmann, 2017;Lahrmann, Madsen, Olesen, Madsen, & Hels, 2018). In this section, a review of previous studies on cycling injury severity is presented. ...
Article
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Introduction: Cycling is one of the main forms of transportation in Denmark. However, while the number of traffic crash fatalities in the country has decreased over the past decade, the frequency of cyclists killed or seriously injured has increased. The high rate of serious injuries and fatalities associated with cycling emphasizes the increasing need for mitigating the severity of such crashes. Method: This study conducted an in-depth analysis of cyclist injury severity resulting from single and multiparty bicycle-involved crashes. Detailed information was collected using self-reporting data undertaken in Denmark for a 12-month period between 1 November 2012 and 31 October 2013. Separate multilevel logistic (MLL) regression models were applied to estimate cyclist injury severity for single and multiparty crashes. The goodness-of-fit measures favored the MLL models over the standard logistic models, capturing the intercorrelation among bicycle crashes that occurred in the same geographical area. Results: The results also showed that single bicycle-involved crashes resulted in more serious outcomes when compared to multiparty crashes. For both single and multiparty bicycle crash categories, non-urban areas were associated with more serious injury outcomes. For the single crashes, wet surface condition, autumn and summer seasons, evening and night periods, non-adverse weather conditions, cyclists aged between 45 and 64 years, male sex, riding for the purpose of work or educational activities, and bicycles with light turned-off were associated with severe injuries. For the multiparty crashes, intersections, bicycle paths, non-winter season, not being employed or retired, lower personal car ownership, and race bicycles were directly related to severe injury consequences. Practical Applications: The findings of this study demonstrated that the best way to promote cycling safety is the combination of improving the design and maintenance of cycling facilities, encouraging safe cycling behavior, and intensifying enforcement efforts.
... On the other hand, using visibility aids to increase visibility is equally important, especially when cycling in low-light conditions [10,11]. Visibility aids can increase the distance at which car drivers detect cyclists at night [12,13]. Currently, front reflectors, static lights, and flashing lights are widely used to improve cyclist visibility at night [14][15][16]. ...
Article
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In recent years, bike sharing has increasingly spread across the world. Compared with personal bikes, shared bikes are uniform and have bright surfaces to help the public to find them easily. At the same time, unfamiliarity is still a problem for some users of shared bikes. Therefore, these features should be understood to improve the night visibility of cyclists and improve traffic safety. Our study tested and compared differences in night visibility using five types of visibility aids. The results showed two cognitive differences between cyclists and drivers. First, cyclists believed that using flashing lights or static lights would provide better visibility than other visibility aids. However, using a static light and reflectors showed better results in our research. Secondly, compared to private bikes, cyclists showed more confidence in the nighttime visibility of shared bikes, especially with retroreflective strips. But the behavior of drivers in our study did not support such differences. A post-experiment survey was conducted to explore such cognitive differences, and showed that unfamiliarity with these strips was a possible reason for driver unawareness. This study will aid policy makers in incorporating suitable visibility aids within bike-sharing programs. Further, this study includes helpful advice for cyclists in terms of improving their night visibility.
... Contribution in improving this area can be seen in the studies of more recent dates (Cavallo & Pinto, 2012;Elvik, 2013;Peña-garcía, De Oña, García, Peñagarcía, & de Oña, 2014;Pinto, Cavallo, & Saint-Pierre, 2014;Ranch, Cavallo, Dang, & Vienne, 2016), too. Various studies on the effects of DRL on road safety were conducted for bicycles and motorcycles (FORS 1990;Madsen, Andersen, & Lahrmann, 2013;Pinto et al., 2014;Ranch et al., 2016;Nagayama et al. 1980). Simultaneously, researches relating the effects of DRL on traffic safety level of passenger cars improvement were performed. ...
Article
Research trying to determine the impact of the use of daytime running lights (DRL), in vehicles, on road safety are lasting throughout the decades. The largest number of previous studies were focused on the search for a relationship between the use of daytime running lights and the number of traffic accidents. As the occurrence of accidents is affected by many factors, this paper examines whether there are differences in driveŕs estimation of passenger car speed when daytime running lights are turned on or off. In order to examine these issues in more details, driving simulator research was conducted. The respondents estimated passenger car speed of 30 km/h, 50 km/h, 70 km/h and 90 km/h, in both conditions (with and without DRL). The results of this research clearly indicate that there are differences in the estimation of passenger car speed when DRL are turned on or off. These differences are statistically significant for higher vehicle speeds (70 km/h and 90 km/h). Furthermore, demographic factors, frequency of driving, as well as involvement in traffic accidents, show significant impact on vehicle speed estimation. The recommended measures (that imply the usage of the DRL only outside of the residential areas), would greatly contribute to the protection and preservation of the environment, primarily in built-up areas.
... Safety has been a long-lasting concern for cyclists in urban transport networks (Karsch, Hedlund, Tison, Leaf, & Group, 2012;Lee, Simons-Morton, Klauer, Ouimet, & Dingus, 2011;Mokhtari, 2011), and as a result, numerous studies have focused on potential factors contributing to perceived risk in cycling context. Studies show that proximity of bicycle lanes to intersections, presence of pedestrians (Ahmadi & Karimi, 2017), low visibility (Madsen, Andersen, & Lahrmann, 2013;Ahmadi & Karimi, 2017), high volume of motor vehicles (Allen-Munley, Daniel, & Dhar, 2004;Klop & Khattak, 1999;Turner, Francis, Roozenburg, & Transport, 2006), presence of heavy vehicles (Nabizadeh, Tafazoli, & Naraghi, 2011), high speed limit (Allen-Munley et al., 2004), lack of traffic calming facilities such as chicanes, speed humps, speed camera and traffic diverters (Minikel, 2012) are among important factors contributing to bicycle safety. Lack of safety significantly discourages the public from using bicycles especially if the cycling infrastructure is shared with motorized vehicles -which is commonly referred to as "shared bicycle lane". ...
... Wearing fluorescent materials in the day-time decreased bicycle crashes and improved detection and recognition distance (Kwan and Mapstone, 2004;Porchia et al., 2014;Thornley et al., 2008). Using retro-reflective clothing (a reflective bicycle vest, ankle and knee reflectors), lamps and flashing lights increased the distance at which the car drivers detect cyclists at night (Kwan and Mapstone, 2004;Madsen et al., 2013;Porchia et al., 2014;Watts, 1984;Wood et al., 2012). ...
Article
Objective: The aim of this study was to evaluate the visibility of cyclists for motorists in a simulated car driving task. Background: In several cases involving collisions between cars and cyclists, car drivers failed to detect the latter in time to avoid collision because of their low conspicuity. Method: 2 groups of motorists (29.2 years old), including 12 cyclist-motorists and 13 non-cyclist-motorists, performed a vulnerable road user detection task in a car-driving simulator. They had to detect cyclists and pedestrians in an urban setting and evaluate the realism of the cyclists, the traffic, the city, the infrastructure, the car driven and the situations. Cyclists appeared in critical situations derived from previous accounts given by injured cyclists and from cyclists' observations in real-life situations. Cyclist's levels of visibility for car drivers were either high or low in these situations according to the cyclists. Results: Realism scores were similar and high in both groups. Cyclist-motorists had fewer collisions with cyclists and detected cyclists at a greater distance in all situations, irrespective of cyclist visibility. Several mechanisms underlying the cognitive conspicuity of cyclists for car drivers were considered. Conclusion: The attentional selection of a cyclist in the road environment during car driving depends on top-down processing. Application: We consider the practical implications of these results for the safety of vulnerable road users and future directions of research.
... In Wood, Lacharez, et al. (2009), cyclists reported that the distance at which they would be first recognized by a driver was twice that estimated by the drivers, especially at night. Madsen, Andersen, and Lahrmann (2013) have investigated the safety effect of using daytime running lights for bicycles in a 12-month recording of accident rates. They found a reduction by 19% of accidents with personal injury, indicating that the permanent bicycle running light significantly improves traffic safety for cyclists. ...
Article
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Objective: Four studies were conducted to assess bicyclist conspicuity enhancement at night by the application of reflective tape (ECE/ONU 104) to the bicycle rear frame and to pedal cranks. Background: Previous studies have tested the benefits of reflective markings applied to bicyclist clothing. Reflective jackets however need to be available and worn while reflective markings enhance conspicuity without any active behavior by the bicyclist. Method: In the first study, reflective tape was applied to the rear frame. Detection distance was compared in four conditions: control, rear red reflector, high visibility jacket, and reflective tape. In the second study, the same conditions were studied with night street lighting on and off. In the third study, detection and recognition distances were evaluated in rainy conditions. In the fourth study, visibility was assessed with the reflective tape applied to pedal cranks. Results: In the first study, the application of reflective markings resulted in a detection distance of 168.28 m. In the second study, the detection distance with reflective markings was 229.74 m with public street light on and 256.41 m with public street light off. In rainy conditions, detection distance using the reflective markings was 146.47 m. Reflective tape applied to pedal cracks resulted in a detection distance of 168.60 m. Conclusion: Reflective tape applied to the rear bicycle frame can considerably increase bicyclist conspicuity and safety at night. Application: Reflective tape is highly recommended to complement anterior and rear lights in bicycle riding at night.
... The number of studies addressing bicyclists are lower than for motorcyclists, but some single accident studies exist. One is presented in table 2. The tendencies of using bicycle headlights are quite clear in reducing the number of personal injury accidents, but the effect on accidents in twilight is the only which is significant by an accident reduction of 51% (-43; -18) (Madsen et al, 2013). ...
Conference Paper
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The enormous amount of studies on ITSs since the first emerged in 1989 calls for a need to systematize the effects of ITS in order to describe at State-of-the-Art in this field. In recent years, a generic trend of addressing traffic issues associated with the safety of vulnerable road users (VRUs), i.e. pedestrians, bicyclists and motorcycle (MC) riders, has emerged. Examples are ABS for MCs, signalling and lanelights for bicyclists and lighting of pedestrian crossings. There are two main foci of the present paper: The first is the attempt to systematize the safety effects of ITS on the behaviour and accidents involving VRUs. It is argued that ITS addressing VRUs must distinguish between the three VRU-groups and thus acknowledge the heterorgeneity between these groups. The second focus is an appraisal of compensation mechanisms as potential outcomes of ITS addressing VRUs, analogous to what has been found for drivers driving cars with ABS, where the safety outcomes are negligible compared to what was expected for this ITS, a phenomenon attributed to behaviour adaptation. Contrary to ABS in cars, ABS on motorcycles reduces fatal and pesonal injury accidents significantly, a result that demonstrate that driver beaviour modelling is significantly different from rider behaviour modelling. It must be emphesized that the present study is only an attempt of systematization: While ITS addressing MCs possibly can be regarded as close to complete, the sections addressing pedestrians and bicyclists are incomplete. Some proposed directions of where to proceed for these two groups are suggested.
... Impaired visibility prevents car drivers and bicyclists from becoming aware of one another until late. Visibility is important for bicyclists and other road users, especially in intersections (Wulf et al., 1989), since increasing bicyclist's visibility can increase safety (see, e.g., Madsen, Andersen, & Lahrmann, 2013). Thus, bicycle lights and reflectors (see project Aura under http://aurabicycles.com) as well as proper street lighting might address the visibility issues. ...
Article
Research in cycling safety seeks to better understand bicycle-related crashes and injuries. The present naturalistic cycling study contributes to this research by collecting data about bicyclists' behavior and impressions of safety-critical situations, information unavailable in traditional data sources (e.g., accident databases, observational studies). Naturalistic data were collected from 16 bicyclists (8 female; M = 39.1 years, SD = 11.4 years) who rode instrumented bicycles for two weeks. Bicyclists were instructed to report all episodes in which they felt uncomfortable while riding (subjective risk perception), even if they didn't fall. After data collection, the bicyclists were interviewed in detail regarding their self-reported safety-critical events. Environmental conditions were also recorded via video (e.g., road surface, weather). In total, 63 safety-critical events (56 non-crashes, 7 crashes) were reported by the bicyclists, mainly due to interactions with other road users - but also due to poorly maintained infrastructure. In low-visibility conditions, vehicle-bicycle and bicycle-bicycle events were the most uncomfortable for the bicyclists. Self-reported pedestrian-bicycle events primarily consisted of pedestrians starting to cross the bicycle path without looking. With one exception, all crashes found in the study belonged to poorly maintained road and infrastructure. In particular, construction work or obstacles in the bicycle path were reported as uncomfortable and annoying by the bicyclists. This study shows how naturalistic data and bicyclists' interviews together can provide a more informative picture of safety-critical situations experienced by the bicyclist than traditional data sources can.
... One form is a field trial of a new technology. For example, Madsen et al. 39 examined the benefits of permanent running bicycle lights in a study in Denmark. These lights were permanently fixed to bicycles, thus avoiding the possibility of forgetting to use lights, and were powered by magnets fitted to bicycle spokes to avoid battery problems. ...
Article
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While UK governments have recently sought to increase cycling activity it remains a minority interest. One reason for this is the perceived danger of cycling on roads filled with traffic. There is statistical evidence to support this perception; for equal exposure, cyclists are more likely to be seriously injured than either drivers or pedestrians. Lighting has a role to play in reducing the hazards of cycling by enhancing the visibility and conspicuity of cyclists. Unfortunately, it is not at all clear that the current lighting regulations and recommendations for cycling and cyclists are the best that can be achieved or are even adequate for these purposes. A number of actions are suggested that should enable lighting’s contribution to the safety of cyclists to be realized.
... La conspicuité des cyclistes est aussi liée à l'éclairage sur les vélos. Il est obligatoire de nuit et son efficacité est aussi parfois avancée de jour [143]. Néanmoins, l'efficacité du dispositif est amoindrie car les cyclistes ne s'en équipent pas forcément (malgré l'obligation figurant au code de la route) et, lorsqu'ils le sont, les lumières avant et/ou arrière ne fonctionnent pas né- cessairement. ...
Article
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In many major cities, the growing modal share of cycling, mainly supported by public policies, raises the issue of cycling safety. Most of the existing work on this topic is based on police data. However, these data underreport cyclists, especially the victims of single accidents. In France, a recent study based on the Rhône road trauma registry, a medical database covering almost all cyclist falls or collisions, considers that a cyclist is 8 times more likely to be injured than a driver by hour spend on a road. The same review also reveals an increased risk of crash for women. Based on these observations, this thesis comes up with a full picture of cycling accidents, taking into account accident factors identified in the literature. The proposed work offers a better understanding on how the cyclist’s behavior interacts with them. It aims to describe accident configurations to propose preventive primary and secondary safety actions. To do so, we surveyed 3337 cyclists injured in 2009-2011 and identified in the Rhône Road Trauma Registry. Based on a significant response rate, descriptive analyses improve existing knowledge in cycling safety, some accident factors being examined for the first time in our survey. Following these analyses, gender roles were unclear, justifying an intensive investigation on cycling accidents through the prism of gender. In order to achieve this goal, we select the 44 accidents on utilitarian trips and built a logistical regression model to explain the likelihood that the victim is a woman. All factors being equal, when a injured cyclist had a load on his bike, did not know the route, fell ascending or descending a curbside, it is more likely that the victim is a woman. Conversely, the probability for the victim to be a men increases if the cyclist’s speed is one of the accident factors. These results are confirmed and illustrated analyzing textual data on accidents stories. The last part is dedicated to a proposal of a set of actions and ideas aiming at improving cycling safety. Some research perspectives are proposed to address the weaknesses of the thesis work
... The half of them used permanent running light on virtually all bicycle trips and the other half did not. The permanent running light reduced the number of accidents with 19%, and the clearest effect was found under daylight conditions (Madsen et al., 2013). The other study was on an all-time use of a coat with reflectors for bicyclists. ...
Article
Almost half of all traffic fatalities worldwide are non-motorised road users (NMRUs). In Denmark, the number has increased with about 30%. NMRUs consist of about 63% of the injured in the Danish traffic. Much has been done to reduce the number of injured NMRUs with counterparts, while little effort is put into the reduction of the vast majority of the accidents, NMRU single accidents, which are about 90% of all injured NMRUs. There are no efficient tools available to reduce this number. A significantly better designed, maintained, and illuminated road network would most likely help. However, that is expensive and not possible for most road authorities. Despite this, the challenges with NMRUs in single accidents need more attention, if road safety is to be improved. The situation in Denmark is more than likely the case in many other countries as well; although the documentation is scarce.
... supporting previous conclusions about the importance of bicyclists' visibility from earlier studies 10 (Madsen, et al., 2013;Wulf, et al., 1989). Further, as attributable risk was the highest for 11 intersections, our data suggest that countermeasures to bicycle accidents have a higher potential (in 12 absolute numbers) when targeting intersections compared to road surface issues. ...
Article
Presently, the collection and analysis of naturalistic data is the most credited method for understanding road user behavior and improving traffic safety. Such methodology was developed for motorized vehicles, such as cars and trucks, and is still largely applied to those vehicles. However, a reasonable question is whether bicycle safety can also benefit from the naturalistic methodology, once collection and analyses are properly ported from motorized vehicles to bicycles. This paper answers this question by showing that instrumented bicycles can also collect analogous naturalistic data. In addition, this paper shows how naturalistic cycling data from 16 bicyclists can be used to estimate risk while cycling. The results show that cycling near an intersection increased the risk of experiencing a critical event by four times, and by twelve times when the intersection presented some form of visual occlusion (e.g., buildings and hedges). Poor maintenance of the road increased the risk tenfold. Furthermore, the risk of experiencing a critical event was twice as large when at least one pedestrian or another bicyclist crossed the bicyclist’s trajectory. Finally, this study suggests the two most common scenarios for bicycle accidents, which result from different situations and thus require different countermeasures. The findings presented in this paper show that bicycle safety can benefit from the naturalistic methodology, which provides data able to guide development and evaluation of (intelligent) countermeasures to increase cycling safety.
Article
Bicyclists are vulnerable road users who are at a greater risk for injury and fatality during crashes. Additionally, the “near-miss” incidents they experience during regular trips can increase the perceived risk and deter them from riding again. This paper aims to use naturalistic bicycling data collected in Johnson County, Iowa to: 1) study the effect of factors such as road surface type, parked vehicles, pavement markings and car passing events on cyclists’ physiological stress and 2) understand the effect of daytime running lights (DRL) as an on-bicycle safety system in providing comfort to cyclists and highlight of their presence on the road to other vehicles. A total of 37 participants were recruited to complete trips over two weekends, one weekend with DRL and the other without DRL. Recruitment was specifically targeted toward cyclists who expressed discomfort riding in traffic. Data were collected using a front forward facing camera, GPS, and a vehicle lateral passing distance sensor mounted on the bicycle and a Empatica E4 wrist band (providing physiological data such as electrodermal activity; EDA) worn by the cyclist. Data from those sources were cleaned, processed, merged, and aggregated into time windows depicting car passing and no car passing events. Mixed effects models were used to study the cyclists’ skin conductance response (phasic EDA) and baseline skin conductance level (tonic EDA). Car passing, parked vehicles, and roads with dashed centerline markings were observed to increase the cyclists stress. The use of DRL had negligible impact on cyclist stress on roads.
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Cahiers de l'Observatoire de la mobilité de la Région Bruxelles-Capitale, 2020 Ce septième Cahier vient compléter la collection des Cahiers de l’Observatoire de la mobilité de la Région de Bruxelles-Capitale (RBC). Après avoir traité de l’offre de transport, des pratiques de déplacement en général et de celles liées au travail et à l’école en particulier, de logistique et de transport de marchandises, ou encore de partage de l’espace public entre tous les modes, ce nouveau Cahier s’arrête pour la première fois sur un mode spécifique : le vélo. Cette publication comporte trois parties. La première offrira une brève histoire du vélo racontée depuis Bruxelles et évitera d’emblée toute naturalisation du phénomène : le lent déclin du vélo au cours de la seconde moitié du 20e siècle résulte d’évolutions structurelles et non d’explications selon lesquelles Bruxelles ne serait " pas faite pour le vélo ". Cette première partie comportera également une mise en contexte institutionnelle afin d’identifier qui sont les acteurs compétents en matière de politique cycliste et la place occupée par celle-ci dans les outils réglementaires et planologiques régionaux, ainsi que dans ses budgets. Elle se terminera par une définition et une typologie des vélos et autres engins de déplacement légers. La deuxième partie du Cahier abordera la pratique du vélo en RBC à travers une analyse approfondie du parc vélo et des déplacements à vélo. Enfin, la troisième partie analysera la cyclabilité de la Région : les aménagements pour le vélo en mouvement, la sécurité et l’insécurité des cyclistes, le stationnement des élos et les services liés au vélo. Une conclusion générale viendra clore ce vaste exercice de synthèse. À noter que les données mobilisées dans ce Cahier ont été arrêtées en juillet 2019. Il va de soi qu’une actualisation régulière de cette synthèse sera nécessaire pour suivre l’évolution de ce secteur en pleine ébullition.
Article
For safety purposes, it is critical that bicyclists be conspicuous to drivers. We report two experiments that investigated the benefits of bicycle taillights and fluorescent clothing for enhancing the bicyclist’s rear conspicuity in daylight. In Experiment 1, 24 participants sat in a car parked on a closed road at each of three distances and rated the conspicuity of four bicyclists displaying taillights that varied in their placement, intensity, and mode. The results confirmed that bicycle taillights can significantly enhance conspicuity in daylight. Varying the placement of the taillights revealed that having an “always on” taillight mounted to each of the rider’s ankles was the most conspicuous location to mount taillights, and this effect was particularly strong at greater viewing distances. For seat post-mounted taillights, flashing taillights were rated as more conspicuous. In Experiment 2, 186 participants were passengers on a short drive during which they pressed a button each time they recognized that a bicyclist was present. Each participant passed a test bicyclist wearing one of four clothing configurations. When the cyclist wore a fluorescent yellow jersey paired with fluorescent yellow leg covers, participants responded from a distance that was 3.3 times greater than when the cyclist wore the same jersey without the yellow leg covers. Both of these experiments demonstrate that highlighting bicyclists’ pedaling motion enhances their conspicuity when viewed from behind. These results further emphasize the conspicuity benefits of biological motion and provide bicyclists with techniques to enhance their own conspicuity in daylight.
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Purpose: A traffic safety analysis that is based on registered crashes often suffers from underreporting, which may result in biased conclusions and lead to misguided crash-prevention strategies. Self-reporting traffic crashes is a complementary method to obtain crash information that is often not available in official databases. By surveying studies from around the world, this paper aims to map the current practices in the collection of data from self-reporting traffic crashes. Method: A systematic literature search was carried out in three databases, ScienceDirect, Scopus and Transport Research International Documentation (TRID), resulting in 134 reviewed studies. Results: Self-reported crash studies were found to be more common in Europe, North America and Australasia, but there are few studies in developing countries. The reviewed studies mostly focused on adult road users (i.e. legal age of obtaining driving license and with no upper limit) and car users. Questionnaires (either paper based or online) were the most often used method, and 1 year was the most common recall period used. Regardless of its drawbacks, the reviewed studies showed that researchers 'trust' self-reports. Conclusion: More studies should be conducted, especially targeting adolescent and young adults (age of 15-30 years) and vulnerable road users (VRUs). Developing countries should increase their efforts when it comes to using self-reporting to better assess the actual traffic safety situation and produce knowledge-based appropriate safety measures. Utilisation of smartphone application to assist data collection in self-reporting study for in-depth crash analysis should be explored further.
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The main idea behind the self-reporting of accidents is to ask people about their traffic accidents and gain knowledge on these accidents as a supplement to the official records kept by police and/or hospitals. The ways of getting information from people can vary; people may be asked to fill out written questionnaires (either online or paper-based), interviews may be performed (either face-to-face or via telephone) and people may be asked to report their accident via an app on their mobile device. The method for gaining self-reported information thus varies greatly – and so does the information that people are asked to give. In most studies, only the number of accidents in which the respondent was involved is relevant for the researcher. In other studies, respondents are asked about possible accident causation factors, and some studies deal with respondents’ recall of the accident details. In other words, self-reporting can have many different aims depending on the research question that is being investigated.
Article
This paper examines bicyclist, automobile driver, vehicle, environmental, and roadway characteristics that influence cyclist injury severity in order to determine which factors should be addressed to mitigate the worst bicyclist injuries. An ordered probit model is used to examine single bicycle-single vehicle crashes from Virginia police crash report data from 2010 to 2014. Five injury severity levels are considered: fatalities, severe injuries, minor or possible injuries, no apparent injuries, and no injury. The results of this study most notably found automobile driver intoxication to increase the probability of a cyclist fatality six fold and double the risk of a severe injury, while bicyclist intoxication increases the probability of a fatality by 36.7% and doubles the probability of severe injury. Additionally, bicycle and automobile speeds, obscured automobile driver vision, specific vehicle body types (SUV, truck, and van), vertical roadway grades and horizontal curves elevate the probability of more severe bicyclist injuries. Model results encourage consideration of methods to reduce the impact of biking and driving while intoxicated such as analysis of bicycling under the influence laws, education of drunk driving impacts on bicyclists, and separation of vehicles and bicycles on the road. Additionally, the results encourage consideration of methods to improve visibility of bicyclists and expectation of their presence on the road.
Article
In this paper, we propose two potential risk indicators to define and evaluate the safety of bicycle path at the microscopic level. Field bicycle data were collected from three survey sites under different traffic conditions. These two risk indicators based on speed dispersion were proposed and calculated during each 5-min interval. The risk influences of various widths of bicycle path and traffic conditions were analyzed by using one-way ANOVA. We further proposed a generalized linear model (GLM) for modeling and analyzing the relationships between bicycle risks and v/c ratio and percentages of electric bicycles, male cyclists, young cyclists, and loaded cyclists. The stepwise regression models were applied for determination of coefficients. The results show that the influences of gender and age of cyclists on potential risks are not significant. The risks increase with the width of bicycle path and percentage of electric bicycles, while only for wider bicycle path (4-lane case in this study), the risks are associated with whether or not cyclists are loaded. The findings could contribute for analysis and evaluation of the safety for bicycle path.
Article
Road safety developments are correlated with mobility developments, which are in turn affected by socioeconomic factors (level of motorisation, economic growth etc.). During the last few years, road traffic fatalities exhibit important annual reductions in several developed countries; these reductions cannot be justified by policy efforts alone, and are partly attributed to the global economic recession affecting most countries' economy and mobility. The present research aims to associate annual Gross Domestic Product (GDP) changes with the related annual changes in road traffic mortality rates. Mortality rates and GDP per capita data for the period 1975–2011 are used from 27 European countries, for the development of mixed linear models. The results suggest that an annual increase of GDP per capita leads to an annual increase of mortality rates, whereas an annual decrease of GDP per capita leads to an annual decrease of mortality rates. These effects are statistically significant overall, and in different groups of countries (Northern/Western, Central/Eastern and Southern). A one-year lagged effect of annual GDP decrease was found to be significant in Northern/Western countries. These effects may capture annual GDP increases from the improvement in the prosperity level of most European countries, as well as occasional annual GDP decreases as a result of socioeconomic events (e.g. economic recessions, political changes in Central/Eastern European countries in the early nineties etc.). The models proposed in this paper are able to characterise the short-term dynamics of the examined variables, but not their long-run relationships.
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Background: Few international studies examine public bicycle share programs (PBSP) health impacts. We describe the protocol for the International Bikeshare Impacts on Cycling and Collisions Study (IBICCS). Methods: A quasi-experimental non-equivalent groups design was used. Intervention cities (Montreal, Toronto, Boston, New York and Vancouver) were matched to control cities (Chicago, Detroit, and Philadelphia) on total population, population density, cycling rates, and average yearly temperature. The study used three repeated, cross-sectional surveys in intervention and control cities in Fall 2012 (baseline), 2013 (year 1), and 2014 (year 2). A non-probabilistic online panel survey with a sampling frame of individuals residing in and around areas where PBSP are/would be implemented was used. A total of 12,000 respondents will be sampled. In each of the 8 cities 1000 respondents will be sampled with an additional 4000 respondents sampled based on the total population of the city. Survey questions include measures of self-rated health, and self-reported height and weight, knowledge and experience using PBSP, physical activity, bicycle helmet use and history of collisions and injuries while cycling, socio-demographic questions, and home/workplace locations. Respondents could complete questionnaires in English, French, and Spanish. Two weights will be applied to the data: inverse probability of selection and post-stratification on age and sex.A triple difference analysis will be used. This approach includes in the models, time, exposure, and treatment group, and interaction terms between these variables to estimate changes across time, between exposure groups and between cities. Discussion: There are scientific and practical challenges in evaluating PBSP. Methodological challenges included: appropriate sample recruitment, exchangeability of treatment and control groups, controlling unmeasured confounding, and specifying exposure. Practical challenges arise in the evaluation of environmental interventions such as a PBSP: one of the companies involved filed for bankruptcy, a Hurricane devastated New York City, and one PBSP was not implemented. Overall, this protocol provides methodological and practical guidance for researchers wanting to study PBSP impacts on health.
Article
This paper explores the similarities and differences between bicycle and motorcycle crashes with other motor vehicles. If similar treatments can be effective for both bicycle and motorcycle crashes, then greater benefits in terms of crash costs saved may be possible for the same investment in treatments. To reduce the biases associated with under-reporting of these crashes to police, property damage and minor injury crashes were excluded. The most common crash type for both bicycles (31.1%) and motorcycles (24.5%) was intersection from adjacent approaches. Drivers of other vehicles were coded most at fault in the majority of two-unit bicycle (57.0%) and motorcycle crashes (62.7%). The crash types, patterns of fault and factors affecting fault were generally similar for bicycle and motorcycle crashes. This confirms the need to combat the factors contributing to failure of other drivers to yield right of way to two-wheelers, and suggest that some of these actions should prove beneficial to the safety of both motorized and non-motorized two-wheelers. In contrast, child bicyclists were more often at fault, particularly in crashes involving a vehicle leaving the driveway or footpath. The greater reporting of violations by riders and drivers in motorcycle crashes also deserves further investigation.
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Objective: To estimate the incidence and risk of medically or police attended bicycle crashes in a prospective cohort study in New Zealand. Method: The Taupo Bicycle Study involved 2590 adult cyclists recruited from the country's largest cycling event in 2006 and followed over a median period of 4.6 years through linkage to four administrative databases. Incidence rates with Poisson distribution confidence intervals were computed and Cox regression modelling for repeated events was performed. Results: The 66 on-road crashes and 10 collisions per 1000 person-years corresponded to 240 crashes and 38 collisions per million hours spent road cycling. The risk increased by 6% and 8% respectively for an extra cycling hour each week. There were 50 off-road crashes per 1000 person-years. Residing in urban areas and in Auckland (region with the lowest level of cycling), riding in a bunch, using a road bike and experiencing a previous crash predicted a higher risk. Habitual use of conspicuity aids appeared to lower the risk. Conclusion: The risk is higher in urban areas and where cycling is less common, and increased by bunch riding and previous crashes. These findings alongside the possible protective effect of conspicuity aids suggest promising approaches to improving cycle safety.
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Background The aim of this study was to estimate use of helmets, lights, and visible clothing among cyclists and to examine trip and personal characteristics associated with their use. Methods Using data from a study of transportation infrastructure and injuries to 690 adult cyclists in Toronto and Vancouver, Canada, we examined the proportion who used bike lights, conspicuous clothing on the torso, and helmets on their injury trip. Multiple logistic regression was used to examine associations between personal and trip characteristics and each type of safety equipment. Results Bike lights were the least frequently used (20% of all trips) although they were used on 77% of trips at night. Conspicuous clothing (white, yellow, orange, red) was worn on 33% of trips. Helmets were used on 69% of trips, 76% in Vancouver where adult helmet use is required by law and 59% in Toronto where it is not. Factors positively associated with bike light use included night, dawn and dusk trips, poor weather conditions, weekday trips, male sex, and helmet use. Factors positively associated with conspicuous clothing use included good weather conditions, older age, and more frequent cycling. Factors positively associated with helmet use included bike light use, longer trip distances, hybrid bike type, not using alcohol in the 6 hours prior to the trip, female sex, older age, higher income, and higher education. Conclusions In two of Canada’s largest cities, helmets were the most widely used safety equipment. Measures to increase use of visibility aids on both daytime and night-time cycling trips may help prevent crashes.
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This article studies volunteerism through the phenomenon of dropping out. By ascertaining the achievements, difficulties, and dilemmas of volunteers at the Center for Assistance to Victims of Sexual Assault and Domestic Violence, we explored the process of dropping out as an encore to understanding the meaning of volunteerism that ends with abandoning a desired activity. On the basis of a longitudinal study, we argue that dropping out is not always a product of waning motivation—for many volunteers, dropping out was extremely difficult—but rather the outcome of unabridged discrepancies between “ought” and “actual” experiences. Volunteers expect to feel good about themselves. In contrast, the organization expects them to act as free agents who can independently manage feelings of pain and self-doubt. When such discrepancies between expectations and reality occur, feelings of anger and disappointment set in. As a result, devoted volunteers drop out in order to preserve their positive self-feeling. It is our contention that in order to understand the nature of volunteers' dropout and perseverance, close attention should be paid to processes of self-regulation in the context of the specific relations between the volunteers and the organization.
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Sumario: What is the question? -- Defining safety -- Counting accidents -- Prediction and estimation -- Basic building blocks -- The Naive Before-After study -- Improving prediction: factors measured and understood, using a comparison group -- The variability of treatment effect -- Back to the starting point: the Empirical Bayes approach -- A more coherent approach? Bibliografía: P. 275-281
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In October 2002 the first ISA-trial in Belgium was started in Ghent. Thirty-four cars and three buses were equipped with the "active accelerator pedal". In this system a resistance in the accelerator is activated when the driver attempts to exceed the speed limit. If necessary, the driver can overrule the system. The main research goals of the trial in Ghent were to evaluate the effects of ISA on speed-change, traffic safety, drivers' attitude, behaviour and drivers' acceptance. To study these effects of the ISA-system both surveys and logged speed data were analyzed. In the surveys drivers noticed that the pedal assisted them well in upholding the speed limits and that the system increased driving comfort. Most important drawbacks were technical issues. Data analysis shows a reduction in the amount of speeding due to the ISA-system. There is however still a large remaining percentage of distance speeding, especially in low speed zones. Differences between drivers are large. For some drivers speeding even increases despite activation of the system. For less frequent speeders average driving speed almost always increases and for more frequent speeders average speed tends to decrease. With the system, less frequent speeders tend to accelerate faster towards the speed limit and drive exactly at the speed limit instead of safely below, which causes average speeds to go up.
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Although researchers are often concerned with the presence of participant demand, few have directly examined effects of demand on participant behavior. Before beginning the present study, a confederate informed participants (N = 100) of the study's purported hypothesis. Participants then performed a laboratory task designed to evaluate the extent to which they would respond in ways that may confirm or disconfirm the hypothesis of the study. The authors found that participants tended to respond in ways that confirmed the hypothesis, yet this tendency depended on attitudes toward the experiment or experimenter and other individual differences. In addition, results suggested that suspicion probes may be ineffective in measuring participants' previous knowledge and suspicion. Findings indicate the need for more research and consideration of demand in the design of studies and analysis of data.
Article
Regular cycling has been shown to improve health and well-being and has a role in tackling obesity and inactivity. Cycle collisions, particularly those involving motorised vehicles, can lead to significant mortality and morbidity and are currently a barrier to wider uptake of cycling. There is evidence that the conspicuity of cyclists may be a factor in some injury collisions. Low-cost, easy to use retro-reflective and fluorescent clothing and accessories (’conspicuity aids’) are widely available. Their effectiveness in reducing the risk of cycling collisions is currently unknown. This study was designed to investigate the relationship between the use of conspicuity aids and risk of collision or evasion crashes for utility and commuter cyclists in an urban setting in the UK. Methods A matched case-control study was undertaken. Cases were adult commuter and utility cyclists who were involved in a crash resulting from a collision or attempted evasion of a collision with another road user. Cases were recruited at a large UK emergency department. Controls were commuter and utility cyclists matched by time and day of travel, season and geographical area of cycling. Controls were recruited at public and private cycle parking sites. Data on the use of conspicuity aids, crash circumstances, participant demographics, cycling experience, safety equipment use and journey characteristics including an estimate of the bicycle crash risk for each chosen route (the number of previous crashes per 100 million kilometres travelled by bicycle calculated for each participant route) were collected using self-completed questionnaires and maps. Conditional logistic regression was used to calculate crude and adjusted odds ratios and 95% confidence intervals of the risk of a crash involving a collision or evasion of a collision with another road user when cyclists reported they were using any item of fluorescent or retro-reflective clothing or equipment vs. none. Unconditional logistic regression was used to analyse associations between participant characteristics and conspicuity aid use. Continuous variables were dichotomised where there was a non-linear relationship to the bicycle crash outcome variable or the primary exposure variable. The sensitivity of the study models to selection, recall and information biases and the effect of missing data was assessed using independent records of conspicuity aid use by potential participants during recruitment. Observations of conspicuity aid use within the study source population at sites across the study catchment area were also conducted by the researcher during the recruitment phase. Results There were 76 cases and 272 controls cyclists who were eligible for inclusion in the primary analysis (response rate of 13% and 54% respectively). The proportion of cases who reported using any item of fluorescent or reflective materials on their clothing or equipment (excluding bicycle mounted reflectors) was higher than for matched controls (cases users 69.7%; 95% CI 58.1% to 79.8% vs. control users 65.4%; 95% CI 59.5% to 79.1%). The unadjusted odds ratio for a collision or evasion crash when using conspicuity aids, was 1.2 (95% CI 0.66 to 2.17). Two alternative modelling strategies were employed. After adjustment for confounding from age, gender, socio-economic deprivation, number of years of cycling experience, bicycle crash risk along each route and cycle helmet use the odds ratio was 1.77 (95% CI 0.74 to 4.25). After adjustment for confounding from age, gender, socio-economic deprivation, bicycle crash risk along each route and history of previous cycle crash involvement the odds ratio was 2.4 (95% CI 1.06 to 5.7). The odds ratio was not significantly affected by adjustment for possession of a driving licence, reported bicycle safety training in childhood, psychometric associates of risk taking behaviour, cycle helmet wearing, years of experience of cycling, distance or number of trips cycled in the previous seven days, type of bicycle, the use of bike-mounted lights or reflectors, weather or lighting conditions, familiarity with the route or alcohol consumption within 8 hours prior to the recorded journey. There was a significant difference between the measure of bicycle crash risk along each route for cases and controls with controls reporting travelling on routes with lower objective bicycle crash risk (median (IQR); cases 378.5 (232.4 to 548.3) vs. controls 268.5 (192.6 to 464.5); p= 0.006). There were no significant differences in route risk for users vs. non-users of conspicuity aids (route risk median (IQR) for conspicuity aid users vs. non-users; 308.1 (198.0 to 504.3) vs. 272.3 (203.7 to 413.4; p= 0.22). Conspicuity aid use was associated with increased length of participant route (unadjusted OR 3.25 for reported route greater than median; 95% CI 2.04 to 5.17 p<0.001), higher numbers of police-recorded bicycle crashes (unadjusted OR 2.26 for greater than median; 95% CI 1.43 to 3.55; p<0.001) and lower numbers of observed cyclists on each route (unadjusted OR 0.999; 95% CI 0.998 to 1.000 p=0.015). Route risk data were missing for 50 participants (15 cases and 35 controls). Validation of the primary exposure showed that there was moderate agreement between participants’ self-reports and independently collected data (kappa 0.42; 95% CI 0.32 to 0.51) but independent data were collected on only 4 eligible cases. Self-reported use of conspicuity aids was higher amongst cases and controls in this study than that observed for cyclists in the study area during the recruitment period (23%; 95% CI 22% to 24%). Discussion The results of this study show a non-significant increase in the odds of a crash for users compared to non-users of conspicuity aids whilst cycling. This association was increased after adjustment for confounders but most models generated to adjust for confounding remained insignificant. No reduction in crash risk could be demonstrated. This is not consistent with the large body of evidence suggesting that conspicuity aids increase the distances from which wearers can be detected and recognised by drivers in a variety of settings. There was evidence that cases were cycling along routes with greater exposure to traffic danger than controls although there were many participants with missing data for this variable potentially introducing a further source of bias. The route risk estimates did not vary significantly between conspicuity aid users and non-users. Residual confounding may have occurred if conspicuity aid users were taking more risks when encountering similar traffic conditions to non-users. This could not be measured but may go some way to explaining these results. If cyclists over-estimate the likely effect of their conspicuity aid use this could result in over compensation and a net increase in crash risk. Adjustment for route risk may have introduced bias by the loss of some participants from the analysis or by acting as a positive suppressor variable increasing the influence of uncontrolled confounding if conspicuity aid use were leading to risky riding over and above the objective risk arising from differing road and traffic conditions. The association between the odds of crash and travelling on roads with higher incidences of previous cycle crashes and fewer cyclists provides support for the “safety in numbers” effect reported in other studies. Differential selection and misclassification biases may also have resulted in over representation of conspicuity aid users amongst cases compared to controls. Social expectation from involvement in a collision crash may have resulted in cases who were not using conspicuity aids being less likely to participate than controls who were non-users. For similar reasons cases may have been more inclined to over-estimate their conspicuity aid use than controls. Validation data were available for only a small number of cases preventing quantification of exposure-related selection or outcome related misclassification biases and meaning that presence or otherwise of differential bias could not be confirmed. The study was also not able to accurately measure relative conspicuity arising from differences in performance of the conspicuity aids chosen. The differences observed in traffic danger estimates may also be the result of selection bias as recruitment was restricted to public and private cycle parking which may have led to over-representation of controls from areas with greater numbers of cyclists and better infrastructure which are both thought to reduce crash risk. Failure to recruit the required sample size led to low precision in the estimates of odds ratios and an increase in the risk of incorrectly accepting the null hypothesis. Conclusion This study was designed to assess the effect of conspicuity aid use on the risk of crash for commuter and utility cyclists. A slightly greater proportion of cases than controls reported using conspicuity aids. There was therefore a raised odds ratio of collision crash involvement for those using conspicuity aids even after adjustment for a large number of important confounders. The study results do not demonstrate a protective effect as expected given previous work testing the effects of such aids on drivers’ awareness of cyclists and pedestrians. This study demonstrates the importance of understanding why many cyclists remain at risk of collision crash resulting in injury despite the use of conspicuity aids.
Article
Objective: This study aligns to the body of research dedicated to estimating the under-reporting of road crash injuries and adds the perspective of understanding individual and crash factors contributing to the decision to report a crash to the police, the hospital, or both. Method: This study focuses on road crash injuries that occurred in the province of Funen (Denmark) between 2003 and 2007 and were registered in the police, the hospital, or both authorities. Under-reporting rates are computed with the capture-recapture method, and the probability for road crash injuries in police records to appear in hospital records (and vice versa) is estimated with joint binary logit models. Results: The capture-recapture analysis shows high under-reporting rates of road crash injuries in Denmark, and the growth of under-reporting not only with the decrease of injury severity, but also with the involvement of cyclists (reporting rates about 14% for serious injuries and 7% for slight injuries) and motorcyclists (reporting rates about 35% for serious injuries and 10% for slight injuries). Model estimates show that the likelihood of appearing in both datasets is positively related to helmet and seat-belt use, number of motor vehicles involved, alcohol involvement, higher speed limit, and females being injured. Conclusions: This study adds significantly to the literature about under-reporting by recognizing that understanding the heterogeneity in the reporting rate of a road crash may lead to devising policy measures aimed at increasing the reporting rate by targeting specific road user groups (e.g., males, young road users) or specific situational factors (e.g., slight injuries, arm injuries, leg injuries, weekend).
Chapter
This chapter discusses the possible problems in using survey methods in traffic research. For that it concentrates on questionnaires as self-reports. Most of the examples are from driver behaviour questionnaire (DBQ) literature because the DBQ is one of the most widely used instruments for measuring driver behaviors and, thus, provides good demonstration material. Self-reports include a great variety of different methods, including questionnaires and inventories, interviews, focus groups, and driving diaries. Common features in all these diverse self-report measures are that participants are aware that they are participating in a study; they are asked to actively reply to more or less structured questions; and their responses are taken as "face valid"-that is, answers are scored and analyzed based on the responses and not, for example, according to response time or other behavioral or physiological measurement. Self-report methodology has been used for a wide variety of research, including attitudes, opinions, beliefs, emotions, cognitive processes, behaviors, and basically any aspect of driving. Although self-reports can offer a rich source of information, they also have some serious shortcomings and limitation that have to be taken into account. Review of studies using self-report methodology shows that traffic researchers pay far too little attention to the psychometric characteristics and validity of the tests.
Article
Little is known about the effectiveness of visibility aids (VAs; e.g., reflectors, lights, fluorescent clothing) in reducing the risk of a bicyclist-motor-vehicle (MV) collision. To determine if VAs reduce the risk of a bicyclist-MV collision. Cases were bicyclists struck by a MV and assessed at Calgary and Edmonton, Alberta, Canada, emergency departments (EDs) from May 2008 to October 2010. Controls were bicyclists with non-MV injuries. Participants were interviewed about their personal and injury characteristics, including use of VAs. Injury information was collected from charts. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated for VAs during daylight and dark conditions, and adjusted for confounders using logistic regression. Missing values were imputed using chained equations and adjusted OR estimates from the imputed data were calculated. There were 2403 injured bicyclists including 278 cases. After adjusting for age, sex, type of bicycling (commuting vs. recreational) and bicyclist speed, white compared with black (OR 0.52; 95% CI 0.28, 0.95), and bicyclist self-reported light compared with dark coloured (OR 0.67; 95% CI 0.49, 0.92) upper body clothing reduced the odds of a MV collision during daylight. After imputing missing values, white compared with black (OR 0.57; 95% CI: 0.32, 0.99) and bicyclist self-reported light compared with dark coloured (OR 0.71; 95% CI 0.52, 0.97) upper body clothing remained protective against MV collision in daylight conditions. During dark conditions, crude estimates indicated that reflective clothing or other items, red/orange/yellow front upper body clothing compared with black, fluorescent clothing, headlights and tail lights were estimated to increase the odds of a MV collision. An imputed adjusted analysis revealed that red/orange/yellow front upper body clothing colour (OR 4.11; 95% CI 1.06, 15.99) and tail lights (OR 2.54; 95% CI: 1.06, 6.07) remained the only significant risk factors for MV collisions. One or more visibility aids reduced the odds of a bicyclist MV collision resulting in hospitalization. Bicyclist clothing choice may be important in reducing the risk of MV collision. The protective effect of visibility aids varies based on light conditions, and non-bicyclist risk factors also need to be considered.
Article
Bicyclists are among the most vulnerable of road users, with high fatal crash rates. Although visibility aids have been widely advocated to help prevent bicycle-vehicle conflicts, to date no study has investigated, among crash-involved cyclists, the kind of visibility aids they were using at the time of the crash. This study undertook a detailed investigation of visibility factors involved in bicyclist-motor-vehicle crashes. We surveyed 184 bicyclists (predominantly from Australia via internet cycling forums) who had been involved in motor vehicle collisions regarding the perceived cause of the collision, ambient weather and general visibility, as well as the clothing and bicycle lights used by the bicyclist. Over a third of the crashes occurred in low light levels (dawn, dusk or night-time), which is disproportionate given that only a small proportion of bicyclists typically ride at these times. Importantly, 19% of these bicyclists reported not using bicycle lights at the time of the crash, and only 34% were wearing reflective clothing. Only two participants (of 184) nominated bicyclist visibility as the cause of the crash: 61% attributed the crash to driver inattention. These findings demonstrate that crash-involved bicyclists tend to under-rate and under-utilise visibility aids as a means of improving their safety.
Article
An introduction is given to our psychophysical response and valence theory of choice behaviour, since the risk-adaptation theory derives from that theory as an application. Risk-adaptation theory assumes that road users implicitly evaluate their risks by oppositely oriented, single-peaked valence functions of arousal and fear sensations as dependent aspects of risks in road traffic. Due to this dependence and the adaptation to changing risk levels, these single-peaked valence functions combine additively to a dynamic shifting interval of ambivalent risk indifference, where above and below the risk evaluation is increasingly negative. Risk-adaptation theory contains the zero-risk, threat-avoidance, and risk-homeostasis theories as special cases and predicts that: (1) fatality risks decay exponentially, (2) the slope parameter for the exponential fatality risk decay is 1½ larger than for the traffic growth function, (3) a safety measure with a very large effect will be initially compensated to a lesser low risk level than otherwise expected, and (4) the contributions of a road safety measure to danger perception and arousal level determines whether its expected safety effect will be reinforced or adversely compensated. Each prediction is tentatively verified by some research.
Article
A meta-analysis of studies of road accident reporting in official accident statistics made in 13 countries is described here. A rigorous comparison of reporting levels between countries is difficult because of differences in the definitions of reportable accidents, reporting levels, and data sources used to assess reporting levels. Based on 49 studies in 13 countries, it is concluded that reporting of injuries in official accident statistics is incomplete at all levels of injury severity. In rounded values, the mean reporting level in the countries included was found to be 95 percent for fatal injuries according to the 30-day rule, 70 percent for serious injuries (admitted to hospital), 25 percent for slight injuries (treated as outpatients), and 10 percent for very slight injuries (treated outside hospitals). Reporting levels vary substantially among countries, ranging from 21 to 88 percent for hospital-treated injuries. Reporting is highest for car occupants and lowest for cyclists. In particular, single-vehicle bicycle accidents are very rarely reported in official road accident statistics.
Article
Conspicuity limitations make bicycling at night dangerous. This experiment quantified bicyclists' estimates of the distance at which approaching drivers would first recognize them. Twenty five participants (including 13 bicyclists who rode at least once per week, and 12 who rode once per month or less) cycled in place on a closed-road circuit at night-time and indicated when they were confident that an approaching driver would first recognize that a bicyclist was present. Participants wore black clothing alone or together with a fluorescent bicycling vest, a fluorescent bicycling vest with additional retroreflective tape, or the fluorescent retroreflective vest plus ankle and knee reflectors in a modified 'biomotion' configuration. The bicycle had a light mounted on the handlebars which was either static, flashing or off. Participants judged that black clothing made them least visible, retroreflective strips on the legs in addition to a retroreflective vest made them most visible and that adding retroreflective materials to a fluorescent vest provides no conspicuity benefits. Flashing bicycle lights were associated with higher conspicuity than static lights. Additionally, occasional bicyclists judged themselves to be more visible than did frequent bicyclists. Overall, bicyclists overestimated their conspicuity compared to previously collected recognition distances and underestimated the conspicuity benefits of retroreflective markings on their ankles and knees. Participants mistakenly judged that a fluorescent vest that did not include retroreflective material would enhance their night-time conspicuity. These findings suggest that bicyclists have dangerous misconceptions concerning the magnitude of the night-time conspicuity problem and the potential value of conspicuity treatments.
Book
This book discusses several methodological problems in traffic psychology which are not currently recognized as such. Summarizing and analyzing the available research, it is found that there are a number of commonly made assumptions about the validity of methods that have little backing, and that many basic problems have not been researched at all. Suggestions are made as to further studies that should be made to address some of these problems. The book is primarily intended for traffic/transport researchers, but should also be useful for specialized education at a higher level (doctoral students and transportation specialists) as well as officials who require a good grasp of methodology to be able to evaluate research.
Article
Taking part in an experiment is "a special form of social interaction." The S plays a role and places himself under the control of the E; he may agree "to tolerate a considerable degree of discomfort, boredom, or actual pain, if required to do so." The very high degree of control inherent in the experimental situation itself may lead to difficulties in experimental design. The S "must be recognized as an active participant in any experiment." With understanding of factors intrinsic to experimental context, experimental method in psychology may become a more effective tool in predicting behavior in nonexperimental contexts. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Article
The use of lie scales has a fairly long history in psychometrics, with the intention of identifying and correcting for socially desirable answers. This represents one type of common method variance (bias introduced when both predictors and predicted variables are gathered from the same source), which may lead to spurious associations in self-reports. Within traffic safety research, where self-report methods are used abundantly, it is uncommon to control for social desirability artifacts, or reporting associations between lie scales, crashes and driver behaviour scales. In the present study, it was shown that self-reports of traffic accidents were negatively associated with a lie scale for driving, while recorded ones were not, as could be expected if the scale was valid and a self-report bias existed. We conclude that whenever self-reported crashes are used as an outcome variable and predicted by other self-report measures, a lie scale should be included and used for correcting the associations. However, the only existing lie scale for traffic safety is not likely to catch all socially desirable responding, because traffic safety may not be desirable for all demographic groups. New lie scales should be developed specifically for driver behaviour questionnaires, to counter potential bias and artifactual results. Alternatively, the use of a single source of data should be discontinued.
Article
The Intelligent Speed Adaptation (ISA) project we describe in this article is based on Pay as You Drive principles. These principles assume that the ISA equipment informs a driver of the speed limit, warns the driver when speeding and calculates penalty points. Each penalty point entails the reduction of a 30% discount on the driver's car insurance premium, which therefore produced the name, Pay as You Speed. The ISA equipment consists of a GPS-based On Board Unit with a mobile phone connection to a web server. The project was planned for a three-year test period with 300 young car drivers, but it never succeeded in recruiting that number of drivers. After several design changes, the project eventually went forward with 153 test drivers of all ages. This number represents approximately one thousandth of all car owners in the proving ground of North Jutland in Denmark. Furthermore the project was terminated before its scheduled closing date. This article describes the project with an emphasis on recruitment efforts and the project's progress. We include a discussion of possible explanations for the failure to recruit volunteers for the project and reflect upon the general barriers to using ISA with ordinary drivers.
Article
Motorcycles are overrepresented in fatal motor vehicle accidents: The death rate for motorcycle riders of about 35 per 100,000,000 miles of travel compares with an overall vehicle death rate of 2.57 per 100,000,000 miles. In the attempt to reduce the frequency of automobile-motorcycle collisions, numerous studies have manipulated motorcycle and motorcyclist characteristics to enhance conspicuity. In this paper, we give a review of studies that examined the effectiveness of these measures. Subsequently, we take a critical look at the methods used in these studies to evaluate the effectiveness of conspicuity treatments. Furthermore, we identify factors yet to be considered in the empirical research in this area that may contribute to collisions with motorcycles. These include information-processing failures at the identification and decision stage, as well as more or less permanent factors potentially responsible for different information-processing failures. Transient factors related to the failure to detect motorcycles might include alcohol, fatigue/lack of sleep, inattention, and information overload, whereas more permanent factors might include “cognitive” conspicuity and fi eld dependence.
Article
Different systems of intelligent speed adaptation (ISA) have already been tested in the field and large-scale implementation is being discussed. But do we really know how these systems affect drivers during long-term use? Between 2000 and 2003 a total of 61 test drivers had an ISA speed-warning device installed in their vehicles. Data from these trials show that, initially, the device greatly reduced the amount of time the majority of test drivers spent above the speed limit, and to some extent also reduced their mean speeds, but this effect decreased with time. Further analyses of 27 of the 61 test drivers then showed that the activation of the warning system affected different drivers in quite a homogenous way, with regards to attitude, subjective norm and self-reported behaviour, but not with regards to perceived behavioural control. After activation, long-term use did, however, affect the test drivers in a homogenous way with regards to attitude, subjective norm and self-reported behaviour, as well as perceived behavioural control. When considering these results it must be remembered that the device tested was a first generation ISA speed-warning device and with more research we think that different ISA-systems could be improved and the effects made more stable during long-term use.
Article
Studies in Sweden have raised doubts as to the accuracy of road accident statistics in relation to serious and slight injuries. To explore the reliability of British statistics an analysis has been made of a sample of 1200 patients injured in road accidents and attending hospital. These same cases have been traced in the police records on which official statistics are based. All fatal cases were correctly notified but two types of discrepancy occurred among injuries. In a small number of cases re-classification of “serious” and “slight” seemed to be required. A more important discrepancy was that about one-sixth of serious injuries and one third of slight injuries known to the hospital did not appear in the police notifications. This is not surprising in view of the limited scope of compulsory notification. The police mostly know of accidents by the calling of an ambulance or as a result of allegations of traffic infringements. Thus many cases where an ambulance is not called or in which a driver only is injured and no other vehicle is involved, escape notification. Injuries to pedal cyclists are particularly poorly notified. Less than one quarter of those known to the hospital appeared in the official statistics. It is concluded that similar comparisons of hospital and police information should be made elsewhere to confirm whether this sample is representative of the national rate of notification. In the meantime it is suggested that figures for injuries to pedal cyclists and for slight injuries in general should be used with caution.
Article
This review set out to review the extensive literature on response bias, and particularly dissimulating a socially desirable response to self-report data. Various terminological differences are discussed as well as the way test constructors attempt to measure or overcome social desirability response sets. As an example of the research in this field, four types of studies measuring social desirability in the Eysenckian personality measures (MPI, EPI, EPQ) are reviewed. Also studies of faking in psychiatric symptom inventories, and a wide range of other tests are briefly reviewed. Various equivocal results from attempts to determine what makes some measures more prone to social desirability than others. However there appears to be growing evidence that social desirability is a relatively stable, multidimensional trait, rather than a situationally-specific response set. Faking studies may also be used to examine people's stereotypes and images of normality and abnormality, and various studies of‘abnormal groups’ perception of normality are examined. Recommendations for further work in this area are proposed.
Article
Since motorcyclists are over-involved in accidents, it is of some importance to determine whether or not the use of headlights during daylight might lead to a reduction in such accidents. While some U.S. states have laws in this regard, and other places including Australia have recommendations that such a policy become law, a study was made to help a decision as to whether or not the policy should be introduced into New Zealand. Studies reviewed included those of accident characteristics, those concerning daylight running-light use on automobiles, and those involving day time light use on motorcycles. Physiological and psychological reasons for conspieuity (or lack thereof) of an object are also reviewed, as are factors affecting perceptual processes. It is concluded that compulsory usage of motorcycle headlights should be favored and that New Zealand is very likely to have a benefit-cost ratio exceeding l if such a policy is adopted.
Article
An analysis of data from 1508 motorcycle accidents obtained from Victoria Police files for the year 1974 indicates that inadequate motorcycle visibility is an associated factor in 64.5% of automobile/motorcycle collisions. It is the sole identifiable cause of 21.0% of collisions. The conspicuity of the front of the motorcycle is found to be vitally important in these accidents.
Article
Within this research, the police under-reporting of non-fatal road accident casualties in eight European countries was examined by means of a common methodology applied in each country. Eight national studies were carried out using the common methodology, and this allowed to prepare valid estimates of the level of under-reporting of non-fatal road casualties in Europe in a disaggregate form (namely by country, road user type and injury severity). This provided an insight into the variation of road casualty under-reporting in Europe. Moreover, a new common definition for road casualty severity was proposed that makes use of internationally recognised medical standards. This was established by examining two different injury severity standards, the casualty’s length of stay in hospital and the casualty’s maximum AIS score. The under-reporting coefficients developed within this research were applied to estimate the real number of non-fatal serious road accident casualties, according to the new proposed common definition. For almost all countries, the actual number of serious casualties according to the new proposed definition was found lower than the number of police-recorded serious casualties. With the newly estimated number of serious casualties, the values of the ratio of serious casualties to fatalities are much less widespread across countries. These remaining differences can thus be attributed to real differences in road safety between the countries, after having controlled for the different under-reporting levels and injury severity definitions.
Article
The purpose of this study is to gain insight into bicycle accidents. Bicycle accident data and weekly exposure data were prospectively collected for one year to calculate the incidence rate (IR) of bicycle accidents. An accident was included if it occurred during utilitarian cycling, resulting in an acute injury with corporal damage. If an accident occurred, a detailed questionnaire was filled out to collect detailed information about its circumstances and consequences. A sample of 1087 regular (≥2 cycling trips to work a week) adult (40±10 years) cyclists was analyzed. Over the 1-year follow-up period, 20,107 weeks were covered, accumulating 1,474,978 cycled kilometers. Sixty-two participants were involved in 70 bicycle accidents, of which 68 were classified as 'minor'. The overall IR for the 70 accidents was 0.324 per 1000 trips (95% CI 0.248-0.400), 0.896 per 1000 h (95% CI 0.686-1.106) and 0.047 per 1000 km (95% CI 0.036-0.059) of exposure. Brussels-capital region is the region with the highest IR (0.086; 95% CI 0.054-0.118), with a significantly (P<0.05) higher IR compared to Flanders (0.037; 95% CI 0.025-0.050). Injuries were mainly caused by 'slipping' (35%) or 'collision with a car' (19%). The accidents caused abrasions (42%) and bruises (27%) to the lower (45%) and upper limbs (41%). Police, hospital emergency department or insurance companies were involved in only 7%, 10% and 30% of the cases, respectively. It is noteworthy that 37% of the participants indicated that they could have avoided the accident. In order to decrease the number of accidents, measures should be taken to keep cycling surfaces clean and decrease the number of obstacles on bicycle infrastructure. Roads and intersections need to be built so that the collisions between cars and bicycles are decreased to a minimum. Car drivers and cyclists should pay more attention towards each other. Underreporting of minor bicycle accidents in Belgium is confirmed, and is higher than expected. Reliable accident statistics, taking into account exposure, are needed to decide which road safety measures are the most effective. The 'safety in numbers' principle is also applicable for minor bicycle accidents.
Article
Bicycle injuries, particularly those resulting from single bicycle crashes, are underreported in both police and hospital records. Data on cyclist characteristics and crash circumstances are also often lacking. As a result, the ability to develop comprehensive injury prevention policies is hampered. The aim of this study was to examine the incidence, severity, cyclist characteristics, and crash circumstances associated with cycling injuries in a sample of cyclists in Queensland, Australia. A cross-sectional study of Queensland cyclists was conducted in 2009. Respondents (n=2056) completed an online survey about their cycling experiences, including cycling injuries. Logistic regression modelling was used to examine the associations between demographic and cycling behaviour variables with experiencing cycling injuries in the past year, and, separately, with serious cycling injuries requiring a trip to a hospital. Twenty-seven percent of respondents (n=545) reported injuries, and 6% (n=114) reported serious injuries. In multivariable modelling, reporting an injury was more likely for respondents who had cycled <5 years, compared to ≥ 10 years (p<0.005); cycled for competition (p=0.01); or experienced harassment from motor vehicle occupants (p<0.001). There were no gender differences in injury incidence, and respondents who cycled for transport did not have an increased risk of injury. Reporting a serious injury was more likely for those whose injury involved other road users (p<0.03). Along with environmental and behavioural approaches for reducing collisions and near-collisions with motor vehicles, interventions that improve the design and maintenance of cycling infrastructure, increase cyclists' skills, and encourage safe cycling behaviours and bicycle maintenance will also be important for reducing the overall incidence of cycling injuries.
Article
Few data exist on the risk of injury while commuting to work or school by bicycle. The proportion of commuters choosing to travel by bike is increasing in the United States, and information on injury incidence and the influences of rider characteristics and environmental factors may suggest opportunities for prevention actions. Bicycle commuters in the Portland, OR, metropolitan area were recruited via the websites and community advertising to participate in a 1-year study. Riders completed an initial online survey along with 12 monthly surveys describing their commutes and injury events from September 2007 to August 2008. A traumatic event was considered a serious traumatic event if medical attention was sought. Nine hundred sixty-two adult bicyclists (52% men and 48% women) with a mean age of 36.7 ± 0.4 years (range, 22-70 years) commuted an average of 135 miles (range, 7-617) per month. There were 225 (23%) beginner, 256 (27%) intermediate, and 481 (50%) advanced riders. Four hundred twenty (44%) had a prior traumatic event. Over the 1-year period, 164 (18%) riders reported 192 traumatic events and 49 (5%) reported 50 serious traumatic events. The incidence rates of traumatic events and serious traumatic events were 15.0 (95% CI, 13.2-17.5) and 3.9 (95% CI, 2.9-5.1) per 100,000 miles commuted. There were no differences in age, gender, safety practices, and experience levels between commuters who experienced a traumatic event and those who did not. Approximately 20% of bicycle commuters experienced a traumatic event and 5% required medical attention during 1 year of commuting. Traumatic events were not related to rider demographics, safety practices, or experience levels. These results imply that injury prevention should focus on improving the safety of the bicycle commuting environment.
Article
The use of lie scales to control for common method variance in driver behavior inventories has been very limited. Given that such questionnaires often use self-reported safety variables as criteria, and have social implications, the risk of artefactual associations is high. A questionnaire containing scales from several well known driver inventories that have been claimed to predict traffic accident involvement was distributed three times to a group of young drivers in a driver education program, as well as a random group twice. The Driver Impression Management scale (DIM) was used to control for socially desirable responding. For all behavior scales, the correlation with the DIM scale was substantial. If a scale correlated with self-reported crashes, the amount of predictive power was more than halved when social desirability was controlled for. Results were similar for both samples and all waves. The predictive power of the behavior scales was not increased when values were averaged over questionnaire waves, as should have been the case if the measurement and predictive power were valid. Results were similar for self-reported penalty points. The present results indicate that even the most well-known and accepted psychometric scales used in driver research are susceptible to social desirability bias. As social desirability is only one of a number of common method variance mechanisms that can create artefactual associations, and the great popularity of the self-report methodology, the problem for traffic research is grave. Organizations that fund traffic safety research need to re-evaluate their policies regarding what methods are acceptable. The use of self-reported independent and dependent variables can lead to directly misleading results, with negative effects on traffic safety.
Article
This study explored the beliefs and attitudes of cyclists and drivers regarding cyclist visibility, use of visibility aids and crashes involving cyclists and motorists. Data are presented for 1460 participants (622 drivers and 838 cyclists) and demonstrate that there are high rates of cyclist-vehicle crashes, many of which were reported to be due to the driver not seeing the cyclist in time to avoid a collision. A divergence in attitudes was also apparent in terms of attribution of responsibility in cyclist-vehicle conflicts on the road. While the use of visibility aids was advocated by cyclists, this was not reflected in self-reported wearing patterns, and cyclists reported that the distance at which they would be first recognised by a driver was twice that estimated by the drivers. Collectively, these results suggest that interventions should target cyclists' use of visibility aids, which is less than optimal in this population, as well as re-educating both groups regarding visibility issues.
Article
The use of daytime running lights was made mandatory for new cars in Norway in 1985 and for all cars in 1988. This paper examines the effectiveness of this regulation as an accident countermeasure. The paper relies on the same study design and method of analysis as previous studies of similar laws in Finland and Sweden. Four hypotheses concerning the effects of daytime running lights are tested. None of them was supported. The total number of multiparty accidents in daylight was not reduced. Pedestrian accidents and accidents in twilight were not reduced. The number of rear-end collisions increased by about 20%. Daytime running lights appear to reduce daytime multiparty accidents only during summer (by about 15%) and only for multivehicle accidents, excluding rear-end collisions. The possibility that confounding factors may have influenced study results is examined. It is concluded that such an influence cannot be ruled out. The discussion of the results highlights the difficulties of reaching clear and defensible conclusions in nonexperimental accident research of the kind reported in this paper.
Article
A meta-analysis of 17 studies that have evaluated the effects on traffic safety of using daytime running lights (DRL) on cars is presented. A distinction is made between studies that have evaluated the effects of DRL on the accident rates of each car using it and studies that have evaluated changes in the total number of accidents in a country following the introduction of mandatory use of DRL. Three different definitions of the measure of safety effects are compared and their validity discussed. It is concluded that the use of DRL on cars reduces the number of multi-party daytime accidents by about 10-15% for cars using DRL. The estimated effects on the total number of accidents of introducing DRL laws are somewhat smaller, 3-12% reduction in multi-party daytime accidents, and are likely to contain uncontrolled confounding effects. There is no evidence to indicate that DRL affects types of accident other than multi-party daytime accidents.
Article
Previous research has indicated that safety measures may lead to behavioural adaptation (also termed risk compensation) among road users, partly or completely offsetting the intended safety effects. There is, however, limited knowledge about characteristics of safety measures possibly determining the occurrence of behavioural adaptation. The present study addresses the relationship of driving behaviour to two different kinds of in-car safety equipment, airbags and antilock braking systems (ABS). It is hypothesized that accident-reducing measures like ABS are compensated for to a larger extent than injury-reducing measures like an airbag. On-road unobtrusive measurements of speed, headway, lane occupancy, lane changes, and variability of lateral position were performed on 213 taxis, on the basis of video recordings of traffic travelling to Oslo airport. The behavioural data were matched to questionnaire information collected when the taxis arrived at the airport. In addition to information regarding ABS and airbags, the drivers reported personal background information and answered questions about driving behaviour. Taxis with ABS had significantly shorter time headways than taxis without ABS. There were no relationships with speed, possibly because dense traffic during the observation period may have prevented the drivers from driving at their preferred speed. Simple comparisons also showed fewer lane changes and a lower rate of seat-belt use among drivers of taxis with ABS. However, multiple regression analyses indicated that the latter effects might be explained by driver background factors or by car characteristics other than ABS or airbag. The headway results support the hypothesis of larger compensation for accident-reducing than for injury-reducing measures.
Article
One hundred and eighty-eight bicycle-car accidents in four cities were studied by multidisciplinary in-depth analysis. The sample was representative of the national accident statistics. All the accidents were analyzed in detail to reconstruct the actual movements of those involved and to assess detection of the other party. In 37% of collisions, neither driver nor cyclist realized the danger or had time to yield. In the remaining collisions, the driver (27%), the cyclist (24%) or both (12%) did something to avert the accident. Two common mechanisms underlying the accidents were identified. First, allocation of attention such that others were not detected, and second, unjustified expectations about the behavior of others. These mechanisms were found to be closely related to the system of two-way cycle tracks and to the fact that the general priority rule is applied to the crossings of a cycle track and a roadway. The most frequent accident type among collisions between cyclists and cars at bicycle crossings was a driver turning right and a bicycle coming from the driver's right along a cycle track. The result confirmed an earlier finding (Accident Analysis and Prevention 28, 147-153, 1996) that drivers turning right hit cyclists because they looked left for cars during the critical phase. Only 11% of drivers noticed the cyclist before impact. Cyclists' behavior was in marked contrast to that of drivers. In these cases, 68% of cyclists noticed the driver before the accident, and 92% of those who noticed believed the driver would give way as required by law. Cyclists with a driving license and those who cycled daily through the accident site were involved in different accident types to other cyclists.
Article
Danish studies of traffic accidents at priority intersections have shown a particular type of accidents. In these accidents a car driver supposed to give way has collided with a bicycle rider on the priority road. Often the involved car drivers have maintained that they did not see the bicycle until immediately before the collision even though the bicycle must have been clearly visible. Similar types of accidents have been the subject of studies elsewhere. In literature they are labelled "looked-but-failed-to-see", because it seems clear that in many cases the car drivers have actually been looking in the direction where the other parties were but have not seen (i.e. perceived the presence of) the other road user. This paper describes two studies approaching this problem. One study is based on 10 self-reported near accidents. It does show that "looked-but-failed-to-see" events do occur, especially for well experienced drivers. The other study based on Gap Acceptance shows that the car driver acceptance of gaps towards cyclists depends on whether or not another car is present. Hypotheses for driver perception and for accident countermeasures are discussed.
Article
The long-term effects of the active accelerator pedal (AAP) were evaluated in the city of Lund in 2000 and 2001. The system, installed in 284 vehicles, produced a counterforce in the accelerator pedal at the speed limit. It could, however be overridden by pressing the accelerator pedal harder. The results showed that test drivers' compliance with the speed limits improved considerably. Reduction in average speeds and less speed variation by the test vehicles indicate a great traffic-safety potential. Travel times were unaffected, while emission volumes decreased significantly.
Article
The UK External Vehicle Speed Control (EVSC) project has made a prediction of the accident savings with intelligent speed adaptation (ISA), and estimated the costs and benefits of national implementation. The best prediction of accident reduction was that the fitting on all vehicles of a simple mandatory system, with which it would be impossible for vehicles to exceed the speed limit, would save 20% of injury accidents and 37% of fatal accidents. A more complex version of the mandatory system, including a capability to respond to current network and weather conditions, would result in a reduction of 36% in injury accidents and 59% in fatal accidents. The implementation path recommended by the project would lead to compulsory usage in 2019. The cost-benefit analysis carried out showed that the benefit-cost ratios for this implementation strategy were in a range from 7.9 to 15.4, i.e. the payback for the system could be up to 15 times the cost of implementing and running it.
Article
A naturalistic experiment used an instrumented bicycle to gather proximity data from overtaking motorists. The relationship between rider position and overtaking proximity was the opposite to that generally believed, such that the further the rider was from the edge of the road, the closer vehicles passed. Additionally, wearing a bicycle helmet led to traffic getting significantly closer when overtaking. Professional drivers of large vehicles were particularly likely to leave narrow safety margins. Finally, when the (male) experimenter wore a long wig, so that he appeared female from behind, drivers left more space when passing. Overall, the results demonstrate that motorists exhibit behavioural sensitivity to aspects of a bicyclist's appearance during an encounter. In the light of previous research on drivers' attitudes to bicyclists, we suggest drivers approaching a bicyclist use physical appearance to judge the specific likelihood of the rider behaving predictably and alter their overtaking accordingly. However, the extent to which a bicyclist's moment-to-moment behaviour can be inferred from their appearance is questionable, and so the tendency for drivers to alter their passing proximity based on this appearance probably has implications for accident probability.
Article
The driving behaviour of participants in the Danish intelligent speed adaptation (ISA) project 'Pay as You Speed' (PAYS) is described. The project is the first ISA project based on Pay as You Drive principles. Thus, the ISA equipment both notifies the driver that he/she is speeding ('information') and applies penalty points which decrease the driver's chance of a potential 30% discount on the cost of his/her automobile insurance ('incentive'). The results presented are based on the first 38 of 180 participants. The key result is that the combination of 'information' and 'incentive' almost eliminated speeding on rural roads while significant reductions in speeding were found also for urban roads and to some extent motorways. On roads with speed limits of 50, 80 and 110 km/h the proportion of distance travelled when speeding was reduced significantly. No significant results were found for motorways with speed limits of 130 km/h. In a future paper the final results from 'PAYS' will be presented.
Missing Data: Sage University Paper Series on Quantitative Appli-cations in the Social Sciences Sage University Papers 07-136 Every Accident is One to Many: Road Safety Starts with You – Towards New Objectives 2001–2012. Danish Ministry of Trans-port; Danish Road Safety Commission
  • P D Allison
  • C Brems
  • K Munch
Allison, P.D., 2001. Missing Data: Sage University Paper Series on Quantitative Appli-cations in the Social Sciences. Sage University Papers 07-136. Sage Publications. Brems, C., Munch, K., 2008. Risiko i trafikken 2000–2007. DTU Transport, Danmarks Tekniske Universitet. Danish Road Safety Commission, 2001. Every Accident is One to Many: Road Safety Starts with You – Towards New Objectives 2001–2012. Danish Ministry of Trans-port; Danish Road Safety Commission. Danmarks Statistik, 2003. Faerdselsuheld 2002: Road Traffic Accidents. Danmarks Statistik. Danmarks Statistik, 2009. Faerdselsuheld 2008: Road Traffic Accidents. Danmarks Statistik.
Kørelys i Danmark – Effektvurdering af påbudt kørelys i dag-timerne
  • L K Hansen
Hansen, L.K., 1993. Kørelys i Danmark – Effektvurdering af påbudt kørelys i dag-timerne. Notat 2/1993, Rådet for Trafiksikkerhedsforskning.
Kørelys – Effektvurdering baseret på uheldstal efter knap 3 års erfaring med kørelys
  • L K Hansen
Hansen, L.K., 1995. Kørelys – Effektvurdering baseret på uheldstal efter knap 3 års erfaring med kørelys. Arbejdsrapport 1/1995, Rådet for Trafiksikkerhedsforskn-ing.