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In The Netherlands, on bicycle paths, single-bicycle accidents, bicycle-bicycle and bicycle-moped accidents constitute a considerable share of all bicyclist injuries. Over three quarters of all hospitalised bicyclist victims in the Netherlands cannot be directly related to a crash with motorised traffic. As the usage of bicycle paths steadily incre...
Context in source publication
Context 1
... TTC concept can only be applied in case of a collision course. The PET value, as initially introduced by Allen et al. (1977), is a measure that also includes the 'near misses'. It is defined as the time between the moment that the first road-user leaves the path of the second and the moment that the second reaches the path of the first (see Fig. 6). The PET value indicates the extent to which they missed each other. In urban areas, PET values of one second and lower are indicated as possibly ...
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... As shown in Table 16.5, observational methods are also commonly used in micromobility studies offering detailed insights into real-world usage patterns and safety, such as field observations [49][50][51][52] and video surveillance [53][54][55][56]. Video surveillance provides a non-intrusive means of gathering large volumes of data over extended periods, enabling the analysis of traffic flow, user behavior, and infrastructure effectiveness without continuous observer presence. ...
... This may require considering factors such as locations with diverse pedestrian and cycling infrastructure [52] or areas likely to attract more bicycle or e-scooter users, such as those with speed limits, mid-blocks, and proximity to biking stations [51]. Additionally, selecting locations for video surveillance might require map analysis, street view information, or on-site surveys to ensure the capture of shared spaces, clear camera views, and the coexistence of different road users [54,56]. ...
... Observations are typically conducted during peak hours of non-motorized traffic [56], commuting hours [51], 2 h periods capturing both the morning and evening peak periods [54] or during the evening commute period. It is generally advisable to collect data during peak travel periods and favorable weather conditions to accurately capture travel behavior when infrastructure use is highest, ensuring that the findings are more relevant to real-world practices compared to data gathered during off-peak times and adverse weather conditions [52]. ...
In micromobility studies, data plays an important role, enabling the assessment of many aspects of mobility. Various data types are used to explore areas such as safety, policy evaluation, urban planning, and environmental sustainability. This chapter reviews the primary data types, sources, and collection methods in micromobility studies, including sensor data, surveys, field observations, built environment data, and archival data sources. Sensor data, such as mobile phone GPS and vehicle sensors, provide detailed insights into mobility patterns and environmental conditions but lack socio-demographic information. Surveys and observations are the primary data sources for user behavior and use of infrastructure. Built environment data examines factors like density, diversity, and design influencing micromobility. Archival data, including media reports and public records, are crucial for policy analysis and safety evaluations. The chapter also includes common practices in data preprocessing to enhance data accuracy, supporting researchers in advancing micromobility studies.
... Eismo dalyvių elgsenos tyrimai atliekami siekiant išsiaiškinti susiformavusius judėjimo įpročius, ypač atsižvelgiant į elgesį, kuris gali kelti pavojų. Remiantis ankstesniais tyrimais (Liang et al., 2021;Van Der Horst et al., 2014) galima pastebėti, kad kelių eismo taisyklių nesilaikymas, neatidumas, pavojingas manevravimas, didelis judėjimo greitis yra dažniausiai pasitaikantys pavojingo elgesio pavyzdžiai. ...
... Lietuvoje nėra vieningos metodologijos, kuri būtų naudojama konfliktinių eismo situacijų analizei, todėl atliekant tyrimą vadovaujamasi olandų eismo konfliktų stebėjimo metodu (angl. Dutch Objective Conflict Technique for Operation and Research (toliau -DOCTOR metodika)) (Kraay et al., 2013) ir juo remiantis atliktu konfliktinių situacijų dviračių takuose tyrimu (Van Der Horst et al., 2014). ...
Straipsnyje nagrinėjami dviračių ir pėsčiųjų eismo konfliktiniai taškai Vilniaus mieste, kurie yra vertinami eismo saugumo požiūriu, atliekami pažeidžiamų eismo dalyvių srautų ir elgsenos tyrimai. Aptariamos dažniausios konfliktinių situacijų priežastys, tokios kaip netinkama infrastruktūra, pavojų eismo dalyviams keliantys veiksmai. Konfliktinės situacijos vertintos remiantis olandų eismo konfliktų stebėjimo metodu. Nustatytos pagrindinės problemos, kurios lemia konfliktinių situacijų gausą bei sunkumą, identifikuotas inžinerinių eismo saugumo priemonių taikymo dviračių ir pėsčiųjų eismo konfliktiniuose taškuose poreikis.
... While the performance is not directly part of the model in Fig 1, it can be argued that a successful application of top-down strategies and good compensatory scanning should lead to high performances as final outcome of the model. Situations were rated as critical if the minimal post-encroachment time was below 1 second [57,58]. ...
Objective
It is currently still unknown why some drivers with visual field loss can compensate well for their visual impairment while others adopt ineffective strategies. This paper contributes to the methodological investigation of the associated top-down mechanisms and aims at validating a theoretical model on the requirements for successful compensation among drivers with homonymous visual field loss.
Methods
A driving simulator study was conducted with eight participants with homonymous visual field loss and eight participants with normal vision. Participants drove through an urban surrounding and experienced a baseline scenario and scenarios with visual precursors indicating increased likelihoods of crossing hazards. Novel measures for the assessment of the mental model of their visual abilities, the mental model of the driving scene and the perceived attention demand were developed and used to investigate the top-down mechanisms behind attention allocation and hazard avoidance.
Results
Participants with an overestimation of their visual field size tended to prioritize their seeing side over their blind side both in subjective and objective measures. The mental model of the driving scene showed close relations to the subjective and actual attention allocation. While participants with homonymous visual field loss were less anticipatory in their usage of the visual precursors and showed poorer performances compared to participants with normal vision, the results indicate a stronger reliance on top-down mechanism for drivers with visual impairments. A subjective focus on the seeing side or on near peripheries more frequently led to bad performances in terms of collisions with crossing cyclists.
Conclusion
The study yielded promising indicators for the potential of novel measures to elucidate top-down mechanisms in drivers with homonymous visual field loss. Furthermore, the results largely support the model of requirements for successful compensatory scanning. The findings highlight the importance of individualized interventions and driver assistance systems tailored to address these mechanisms.
... Advanced technologies such as computer vision, machine learning, and real-time data analysis provide valuable insights and enable proactive safety measures in urban environments. Urban safety measures are constantly evolving in response to changing urban environments, emerging risks, and technological advancements (van der Horst et al., 2013;Islam et al., 2022). Governments, urban planners, community organizations, and urban residents all play important roles in collaborating and implementing effective safety measures to ensure the well-being and security of urban residents (F. ...
... The concept of TTC is typically applicable when two entities are on a collision course. However, Allen et al. (1978) developed the PET value to provide a more comprehensive measure (van der Horst et al., 2013). PET is defined as the time interval between the moment the first road user deviates from the path of the second road user and the moment the second road user crosses the path of the first road user. ...
To progressively analyze the urban factors on different levels of crosswalk road safety, the study focused on developing a video-based safety methodology using a pedestrian and vehicle tracking approach for calculating time-to-collision (TTC) and post-encroachment time (PET) to improve safety in crosswalk areas. The study area is limited to Thammasat University in an urban environment where pedestrian and vehicle traffic across the crosswalk is simulated in controlled scenarios. The dataset was collected using closed-circuit television (CCTV) cameras installed at locations in the study area. The YOLOv8x with BOT-SORT was used to track pedestrians and vehicles from the CCTV videos. The overall mAP was 0.861 with a precision of 0.899, a recall of 0.785, and the objects classifier's average accuracy of 0.786. The TTC and PET values were calculated based on the collected data. These metrics can be used to determine the time required for a vehicle or pedestrian to come to a stop or avoid a collision, as well as the time it takes a vehicle or pedestrian to recover from an evasive movement or when the pedestrian has been hit by the vehicle. The 30 videos of near-miss accident scenarios, where 15 videos of pedestrians and vehicles and 15 videos from disordered persons and vehicles, were used to analyze the TTC and PET values to identify areas for further improvement. From the results, the TTC calculation achieved an accuracy of high risk at 90 percent in all scenarios, while PET values higher than 1.0 second resulted in 18 scenarios.
... Using video-based behavioral observations, the study documented and analyzed mutual conflicts and bicyclist behaviors on these paths. The conflict observation method was employed as a key technique to scrutinize and interpret the recorded data, shedding light on various aspects of interactions and conflicts among users [12]. ...
Ensuring road safety in developing countries, such as Nepal, is critical, especially concerning the design and upkeep of bus stops. However, evaluating safety at these stops in Nepal poses challenges due to unreliable crash data nearby. This study focuses on assessing unsafe acts and causal factors around bus stops along the Birauta Chowk-Srijana Chowk-Mahendrapool-Prithvi Chowk Road Section in Pokhara. It identifies unsafe acts contributing to pedestrian accidents and quantifies associated factors on a scale of Zero to One. Using the Analytical Hierarchy Process (AHP), the study evaluates the danger levels posed by these unsafe acts and prioritizes bus stops for improvements. This approach not only enhances bus stop safety but also offers a systematic method applicable where crash data is scarce. The findings highlight bus stop location at Prithvi Chowk as needing immediate attention due to its low safety level followed by another bus stop in the same area. Factors like inadequate loading area capacity and distant zebra crossings contribute significantly, guiding priority improvements. This research equips road authorities with a roadmap for targeted interventions, enabling strategic resource allocation to uplift overall safety standards at bus stops.
... On paths designated only for bicycles, they move at higher speeds while maintaining the same level of safety [50]. Conflicts between cyclists and other road users may therefore result from the organisation of infrastructure and occur depending on the width of the road, the designated direction of traffic [51], and the space shared with pedestrians [52]. ...
Sustainable development and environmental considerations have resulted in many cities around the world recognising the importance of non-motorised modes of transport. Problems related to the proper development and maintenance of cycling infrastructure have already been the subject of various studies. However, they have mainly dealt with the identification of factors influencing the development of cycle paths and the optimisation of the design of safe and comfortable cycle routes. The influence of individual factors on each other and on the development of cycling infrastructure has not been studied. The research aims of this article are to identify which factors influence the development of bicycle infrastructure, their role and interdependence, and their prioritisation. It also looks at whether there are differences between the opinions of bicycle users and experts professionally involved in the development of bicycle paths in assessing the importance of the factors indicated. As a result of the study, eight factors influencing the development of bicycle infrastructure were identified. Based on the opinions of cyclists and experts, the nature of each factor was analysed. Taking into account the complex relationships between the factors, the key factors contributing to the development of bicycle infrastructure were shown: (1) the planning of bicycle paths, taking into account the separation of individual paths and their continuity, consistency, and length; (2) legal regulations promoting cycling in terms of transportation policy; (3) the elimination of obstacles; and (4) the design of bicycle paths, taking into account the safety, space management, terrain, and attractiveness of the surroundings. The results for both groups of respondents were compared. They indicate that both groups of respondents reported the same factors as the most important, with the only differences being in the order of the importance of the factors. The academic value of this work lies in showing the usability of the underrated original version of DEMATEL methodology in the considered area for key factors. The practical significance of this paper is the provision of a rather simple, yet reliable, tool for addressing the complexity of interrelated issues that make the development of urban infrastructure a cumbersome task.
... The surrogate safety assessment model (SSAM) was applied for the estimation of time-to-collision (TTC) and postencroachment time (PET) as safety indicators. Both TTC and PET were derived from the trajectory data, with a combination of the two deemed sufficient for bicycle-involved conflict analysis (Van Der Horst et al., 2014;Abdel-Aty et al., 2022). TTC measures potential conflicts continuously according to motions and reflects the time required for a collision between two road users; it has been applied for the analysis of traffic conflicts (Lee, 1976;Gettman et al., 2008;Huang et al., 2013;Wu et al., 2018;Xu et al., 2021), and it is generally calculated by: ...
Animosity between drivers and cyclists has existed on urban road networks for many years. Conflicts between these two groups of road users are exceptionally high in the shared right-of-way environments. Benchmarking methods of conflict assessments are mostly based on statistical analysis with limited data sources. The actual crash data would be valuable to understand the features of bike-car collisions, however the available data are spatially and temporally sparse. To this end, this paper proposes a simulation-based bicycle-vehicle conflict data generation and assessment approach. The proposed approach uses a three-dimensional visualization and virtual reality platform, integrating traffic microsimulation to reproduce a naturalistic driving/cycling-enabled experimental environment. The simulation platform is validated to reflect the human-resembled driving/cycling behaviors under different infrastructure designs. Comparative experiments are carried out on bicycle-vehicle interactions under different conditions, with data collected from a total of 960 scenarios. Based on the results of the surrogate safety assessment model (SSAM), the obtained key insights include: (1) scenarios of a high conflict probability do not lead to actual crashes, which suggests that the classic SSM-based measurements such as TTC or PET values may not sufficiently reflect real cyclist-driver interactions; (2) the major cause of conflicts is variation in vehicle acceleration, which suggests that drivers are considered to be the main party responsible for bicycle-vehicle conflict/crash occurrence; (3) the proposed approach is able to generate near-miss events and reproduce interaction patterns between cyclists and drivers, facilitating experiments and data collections which would be typically unavailable for this type of study.
... As Goyani et al. (46) suggested, PET was considered for safety evaluation in this study. In urban areas, PET value of one second or less implies the possibility of a critical (evasion-based) situation (62). In the recorded videos in this study, however, no critical situation was observed. ...
Evidence suggests that mobile phone navigation applications (MPNAs) may reduce road traffic safety by causing a visual distraction. This study aimed to (i) identify a list of road safety-related events (RSREs) that could occur while looking at the MPNA, (ii) examine the effect of app-taxFi drivers’ glances at MPNA on missing of RSREs, (iii) develop any potential new indicator in road traffic safety, and (iv) develop a pyramid of traffic incidents. This study investigated 36 app-taxi drivers in real road traffic circumstances. Data were collected by video recording using a double-lens camera. The events that occurred while the app-taxi driver was looking at the MPNA were extracted, recorded, and classified. A time span of less than one second and a new indicator, namely “seeing the event BEFORE visual distraction” (seBvd), were examined. The data were analyzed using descriptive statistics and non-parametric tests with a significance level of 0.05 in SPSS 18. A list of 23 events was identified. The most frequent event was “presence of pedestrians across the road” (including crossing the road and beside the road 36%). The number of glances at the MPNA had a significant correlation with time span ≤1 s ( p = 0.001, r < 0.6). The total time of looking at the MPNA had a significant correlation with time span >1 s ( p = 0.001, r < 0.6). A pyramid of traffic incidents was developed based on the results. The new seBvd indicator is a binary (positive; negative) surrogate safety measure that can be useful in evaluating the effect of visual distraction on road traffic safety. The introduced pyramid of traffic incidents seems useful in traffic safety.
... Semantic coherence 244 measures the frequency of co-occurrence between a pair of words in each document. Residuals measure the spread of the 245 variance in the multinomial function(Taddy, 2012). Models with higher semantic coherence and lower residuals are there-246 fore preferable. ...
Cycling is an eco-friendly and sustainable mode of transportation. Despite its benefits, the cyclists’ risk of collision is still high when interacting with other road users. This study analyzed self-reported near-miss and collision event descriptions for the United States provided by the crowdsourcing platform, BikeMaps.org. Innovative and efficient analytic methods are needed to generate useful information from unstructured textual data sources in the transportation domain. In this study, explorative text mining, topic modeling, and machine learning are utilized to gain insights from the unstructured textual descriptions of crowdsourced near-miss and collision events. The approaches are used to unveil prevalent words and word associations for near-miss and collision events. Structural Topic Modeling (STM) is deployed to autogenerate latent themes or topics from the event descriptions. The generated topic proportions are used as input in Artificial Neural Networks (ANN) to estimate the cyclist’s propensity to a collision. It was found that cyclists had a higher propensity to a collision in topics that articulated vehicle encroachment to the bike lane, on-street parking close or into the bike lane resulting in dooring, and drivers’ violations at the crosswalk. The results and methodology used in this study can assist engineers, policymakers, and law enforcement officers to proactively reduce potential cyclist collisions, prioritizing areas where cyclist safety improvements are needed, and ultimately promoting bicycle ridership in our communities.
... Furthermore, noncollision safety events (conflicts), ranging from right-of-way encroachments to near-miss experiences, are known to play an important role in cycling motivation and perceived traffic risk [12][13][14], sometimes even more than collisions, since the former are far more frequent than the latter. Though traffic conflict analysis was mostly developed for car driving studies since the 1970s, its use to study cyclist interactions is increasing [15]. ...
... Methods to study traffic conflicts include fixed-site observation [11,[15][16][17] and naturalistic cycling studies using instrumented bicycles [18][19][20][21][22]. Fixed-site observation with a video camera offers an omniscient view on the interactions between the road users, thus allowing researchers to compute many traffic conflict indicators, such as postencroachment time (PET) and time-to-collision (TTC) [11,15,16]. On the other hand, naturalistic cycling studies (or more generally, mobile data collections) offer the potential to cover a broad territory and a wide variety of urban contexts [18,23]. ...
... Methods to study traffic conflicts include fixed-site observation [11,[15][16][17] and naturalistic cycling studies using instrumented bicycles [18][19][20][21][22]. Fixed-site observation with a video camera offers an omniscient view on the interactions between the road users, thus allowing researchers to compute many traffic conflict indicators, such as postencroachment time (PET) and time-to-collision (TTC) [11,15,16]. On the other hand, naturalistic cycling studies (or more generally, mobile data collections) offer the potential to cover a broad territory and a wide variety of urban contexts [18,23]. ...
Urban cycling is increasingly common in many North American cities and has the potential to address key challenges of urban mobility, congestion, air pollution and health. However, lack of safety is often cited by potential bike users as the most important deterrent to cycling. This study aimed to evaluate the effect of cycling facility type on traffic conflict likelihood. Four participants recorded a total of 87 h (1199 km) of video, which was reviewed by trained observers to identify and characterize traffic conflicts, yielding 465 conflicts with vehicles and 209 conflicts with pedestrians. Bootstrapped generalized additive logit regressions (GAM) were built to predict traffic conflict likelihood. Results show that while cycling on an off-street bike path effectively reduces the likelihood of conflict with a vehicle, it increases the probability of conflict with a pedestrian. Bike lanes were associated with an increase in the likelihood of a conflict with a vehicle. Decision makers should favor physically segregated and clearly marked cyclist-only facilities to ensure safe and efficient conditions for commuter cyclists.
