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Studying the role of vision in cycling: Critique on restricting research to fixation behaviour

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Abstract

In a recent study published in Accident Analysis & Prevention, Vansteenkiste et al. (2013) - as one of the first in this field - investigated the visual control of bicycle steering. They undertook the interesting task of testing cyclists' eye fixation behaviour against Donges' two-level model of steering, i.e. the guidance level to anticipate alternations in the course of the road and the stabilization level for lane keeping. Although the laboratory experiment itself is well conducted, we believe that its results cannot be used to test the two-level model of steering as developed for driving. The test track was only 15m long, was completely straight and was known in advance. Accordingly, it did not provide adequate conditions for testing the guidance level. Furthermore, as the experimental lanes were much narrower than real-world cycling lanes, the stabilization level differed considerably from that in the real world. The study by Vansteenkiste et al. (2013) may provide valuable insight into the role of vision in 'precision steering', but, as we discuss in the paper, more elaborate research paradigms are needed to achieve more comprehensive knowledge of the role of vision in real-world cycling and cycling safety.

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... Safe navigation through the traffic environment relies heavily on visual perception (see, e.g. Owsley & McGwin, 2010;Schepers et al., 2013). For cyclists visual information is not only important for the monitoring of traffic hazards, but also for keeping balance (Mäkelä et al., 2015). ...
... Vision and visual attention are important for safe navigation through the traffic environment (e.g. Owsley & McGwin, 2010;Schepers et al., 2013). However, in some instances, the auditory perception of traffic sounds and vehicle movement may be crucial for road users, especially for pedestrians and cyclists. ...
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The impact of quiet electric cars, listening to music and conversing on the phone on cyclists' auditory perception and cycling safety.
... Third, mobile eye tracking is geared toward identifying the objects people fixate. This focus has drawn critique (Schepers et al., 2013), as it provides little insight into the processing of peripheral visual information. Although it is highly likely that cyclists rely a lot on peripheral input, we are not aware of a possibility to investigate its role in a real-world scenario (but see Krukar, Mavros, & Hoelscher, 2020, for an approach in this direction) Fourth, we focused on isovists of the participants' body location (i.e., where they looked from), as we were primarily interested to what extent their current perspective influences their gaze behavior. ...
Article
In this research, we investigate how gaze behavior during urban cycling is affected by subjective risk perception and the local spatial configuration. For this purpose, participants cycled at five defined test locations while wearing a mobile eye tracking system. Next to the fixation duration, we extracted sight vector lengths (i.e., the distance between the current body location and the gaze location) and gaze angles (i.e., the degree to which the gaze deviates from the current travel direction). Concerning risk perception, participants provided a hazard estimate for each test location, as well as information about specific areas they experienced as dangerous. This information was aggregated into a local hazard level across all participants. Finally, the vista space (i.e., the space visible from the current position during a fixation) was quantified via isovist analysis. The results imply that spatially open locations, extending about equally into all directions, increase the level of perceived risk. Depending on the local spatial properties, participants also gaze into different directions, rather than further ahead and into their travel direction. Higher cycling experience and greater familiarity with a location enabled a more foresighted and focused gaze behavior. Our findings underline the importance to provide cyclists not only with enough space and with unobstructed views, but also to limit the space they are required to distribute their attention to.
... Additionally, it is unclear which factors besides the visual functioning play a role in the bicycle use of visually impaired people. The available literature mainly focusses on (corrected to) normal vision [22][23][24][25][26] or the influence of infrastructural factors on accessibility or accident rates [27][28][29][30][31]. Connor [32] gives a number of factors that may be of importance, based on his personal experience as a visually impaired cyclist and rehabilitation counsellor. For example, he suggests that the evenness of the road surface and the person's auditory skills are important factors besides the visual functioning. ...
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Purpose: This study aims to identify the most important factors that influence the independent bicycle use of visually impaired people in the Netherlands. Materials and methods: Both visually impaired people and professionals participated in a two-round online Delphi study (n = 42). In Round 1 the participants identified the factors which they ranked by relevance in Round 2. Results: The participants prioritised environmental factors related to the traffic situation, the characteristics of the infrastructure, and weather and light conditions (Kendall’s W = 0.66). They indicated that the most influencing personal factors are related to personality, traffic experience, and personal background (W = 0.58). Glaucoma was ranked as the most relevant ophthalmic condition (W = 0.74), while glare was regarded as the most important factor with respect to the visual functions (W = 0.78). Conclusions: The factors provided by this study can be used to optimise the independent cycling mobility of visually impaired people. More research is needed to investigate, both, how and to what extent the mentioned factors influence the cycling behaviour.
... 2 There was discussion of the three-level McRuer et al. steering control framework in traffic psychology still in the 1980s, with regard to intermittency in lane keeping, lane change and curve driving tasks Godthelp, 1985Godthelp, , 1986; see section 3 Internal models and predictive control in driving), but more recently traffic psychology seems to develop ideas in the "two-level framework" (e.g. Vansteenkiste et al., 2013;Schepers et al.. 2013). ...
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The authors present an approach to the coordination of eye movements and locomotion in naturalistic steering tasks. It is based on recent empirical research, in particular, in driver eye movements, that poses challenges for existing accounts of how we visually steer a course. They first analyze how the ideas of feedback and feedforward processes and internal models are treated in control theoretical steering models within vision science and engineering, which share an underlying architecture but have historically developed in very separate ways. The authors then show how these traditions can be naturally (re)integrated with each other and with contemporary neuroscience, to better understand the skill and gaze strategies involved. They then propose a conceptual model that (a) gives a unified account to the coordination of gaze and steering control, (b) incorporates higher-level path planning, and (c) draws on the literature on paired forward and inverse models in predictive control. Although each of these (a– c) has been considered before (also in the context of driving), integrating them into a single framework and the authors’ multiple waypoint identification hypothesis within that framework are novel. The proposed hypothesis is relevant to all forms of visually guided locomotion. http:// doi.org./10.1037/bul0000150
... While the amount of research focusing on the role of vision in car driving and walking is considerable, gaze behavior in cycling is still poorly documented. Furthermore, the suitability of car driving models for cycling has been discussed, due to the differences in speed, unrestricted visual and environmental conditions and balance maintenance (Vansteenkiste et al., 2013a,b;Schepers et al., 2013). ...
Article
The increase of cyclist presence in urban areas and of the number of cyclist accidents on roads lead researchers to explore the in-traffic visual behavior and hazard perception of cyclists.In this study the actual cyclist gaze behavior while cycling on bicycle tracks-exclusive or shared with pedestrians is analyzed. The intent is to allow a better comprehension of those elements representing interferences, which can influence user's trip. Field tests were performed in the urban center of Bologna, Italy. 16 participants were asked to wear mobile eye tracking glasses and cycle along a defined route. From gaze data recorded by the mobile eye detector, we analyzed which visual information are detected. By applying fixations detection algorithm and then a frame-by-frame analysis we calculated the proportion of fixations-number and duration-across different areas of interest. Proportion of fixations and fixation time are assumed as a proxy of visual workload. Thus, the relative frequency of fixation has been used to rank those elements that draw cyclist attention.Three are the main outcomes: first, an equilibrium of attention location between the central (trajectory) and lateral parts of the visual scene can be assumed as the optimal cycling visual condition. This condition results compromised when the presence of pedestrians is high. Second, discontinuities of the path (like intersections and crosswalks) and the presence of pedestrians are the elements requiring more attention. Third, the absence of physical and visual separation between cyclists and pedestrians seems to lead to a lack of attention to these risk elements.These outcomes about cyclists' visual behavior allowed to recommend design measures to increase comfort and safety on shared-with pedestrian-cycling paths. Thus, suggestions are addressed in the conclusions. Three are the main outcomes: first, an equilibrium of attention location between the central (trajectory) and lateral parts of the visual scene can be assumed as an optimal cycling visual condition. This condition is compromised when the presence of pedestrians is higher. Second, discontinuities of the path (like intersections and crosswalks) and the presence of pedestrians seem to be the elements requiring more attention. On the exclusive cycling path, the majority of the fixations were spent watching the interruptions of the path with approximately the same frequency both in the central visual area (trajectory and end of the path) as out of this region. Third, the absence of physical and visual separation between cyclists and pedestrians seems to lead to a lack of attention to risky elements, such as intersections and crosswalks. If the presence of pedestrians increase, the time spent monitoring elements as conflicts and risk points is lower. Instead, a higher grade of separation between the two different classes of vulnerable users – cyclists and pedestrians – creates a benefit in terms of cyclist concentration on other elements, e.g. as intersections. Other interesting observations about the adopted visual strategies: firstly, the other cyclists encountered drew the rider’s attention when they were within the target region, in front of the cyclist, rather than in a lateral position -in the OUT region. Instead, pedestrians are detected despite their position with respect to the rider. Probably a cyclist’s trajectory is perceived as more predictable and once the other cyclist has been identified in the target area he/she is not followed further with the gaze, in lateral regions. On the contrary, pedestrian movements are assumed to be more unpredictable in their trajectory and thus more alarming. Secondly, path discontinuities and motorized vehicles at intersections seem to be perceived as hazardous elements on which cyclists concentrate monitoring the central and final visual area of the path. Indeed, for this elements, significant statistical differences resulted only for fixations in the target area, to the end of the path. The results of this research can address designers to consider different design strategies to increase the comfort and perceived safety of cycling lanes, especially, when it is not possible to realize new exclusive bicycle paths. The findings of this work show that when the existent urban space and infrastructures are used, i.e. cycle path on sidewalks, specific design elements should be employed to increase the visual (physical) separation. It has been found that where the presence of pedestrians within the cycling space is more likely, relevant elements such as intersections are less observed -the relative frequency were almost two times lower. For this reason, the adoption of barriers or other physical elements to define cycling lane should be recommended also on sidewalks, not only on road. Indeed, circumstances where the road is used rather than adjacent bike lane on sidewalks are frequently verified. In this work it has been measured that a higher grade of separation between the two different classes of vulnerable users – cyclists and pedestrians – could lead to a benefit in terms of cyclist concentration on other elements. For this reasons, the practice of defining large, open, shared cycling/pedestrian space could not be the best strategy when bicycle paths and corridors have to be planned. Picket fences, light barriers, plant racks, arbors, or trees can be soft –and cheap- measures that can be easily adopted. As it has been showed path discontinuities and motorized vehicles at intersections, seem to be perceived as hazardous elements on which cyclists concentrate. The increase of visual separation and the consequent reduction of visual spread must be combined with a high and clear signaling of conflict points. It resulted that these elements were monitored in the central and final visual area of the path. Thus they should be consequently located: vertical signs should be evident and overhead (not in the middle of the bike lane) to let cyclist visualize them from a sufficient distance - without them to become obstacles.
... Vision and visual attention are important for safe navigation through the traffic environment (e.g. Owsley & McGwin, 2010;Schepers et al., 2013). However, in some instances, the auditory perception of traffic sounds and vehicle movement may be crucial for road users, especially for pedestrians and cyclists. ...
... Vision and visual attention are important for safe navigation through the traffic environment (e.g. Owsley & McGwin, 2010; Schepers et al., 2013). However, in some instances, the auditory perception of traffic sounds and vehicle movement may be crucial for road users, especially for pedestrians and cyclists. ...
Research
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Available online: http://www.sciencedirect.com/science/article/pii/S1369847815001503 Transportation Research Part F: Traffic Psychology and Behaviour
Conference Paper
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The effects of mobile phone use on cycling behaviour were studied. In study 1, the prevalence of mobile phone use while cycling was assessed. In Groningen 2.2% of cyclists were observed talking on their phone and 0.6% were text messaging or entering a phone number. In study 2, accident-involved cyclists responded to a questionnaire. Only 0.5% stated that they were using their phone at the time of the accident. In study 3, participants used a phone while cycling. The content of the conversation was manipulated and participants also had to enter a text message. Data were compared with just cycling and cycling while listening to music. Telephoning coincided with reduced speed, reduced peripheral vision performance and increased risk and mental effort ratings. Text messaging had the largest negative impact on cycling performance. Higher mental workload and lower speed may account for the relatively low number of people calling involved in accidents. STATEMENT OF RELEVANCE: Although perhaps mainly restricted to flat countries with a large proportion of cyclists, mobile phone use while cycling has increased and may be a threat to traffic safety, similar to phone use while driving a car. In this study, the extent of the problem was assessed by observing the proportion of cyclists using mobile phones, sending questionnaires to accident-involved cyclists and an experimental study was conducted on the effects of mobile phone use while cycling.
Article
A driver steering a car on a twisting road has two distinct tasks: to match the road curvature, and to keep a proper distance from the lane edges. Both are achieved by turning the steering wheel, but it is not clear which part or parts of the road ahead supply the visual information needed, or how it is used. Current models of the behaviour of real drivers or 'co-driver' simulators vary greatly in their implementation of these tasks, but all agree that successful steering requires the driver to monitor the angular deviation of the road from the vehicle's present heading at some 'preview' distance ahead, typically about 1 s into the future. Eye movement recordings generally support this view. Here we have used a simple road simulator, in which only certain parts of the road are displayed, to show that at moderate to high speeds accurate driving requires that both a distant and a near region of the road are visible. The former is used to estimate road curvature and the latter to provide position-in-lane feedback. At lower speeds only the near region is necessary. These results support a two-stage model of driver behaviour.
Article
The accident data base of the City of Helsinki shows that when drivers cross a cycle path as they enter a non-signalized intersection, the clearly dominant type of car-cycle crashes is that in which a cyclist comes from the right and the driver is turning right, in marked contrast to the cases with drivers turning left (Pasanen 1992; City of Helsinki, Traffic Planning Department, Report L4). This study first tested an explanation that drivers turning right simply focus their attention on the cars coming from the left-those coming from the right posing no threat to them-and fail to see the cyclist from the right early enough. Drivers' scanning behavior was studied at two T-intersections. Two well-hidden video cameras were used, one to measure the head movements of the approaching drivers and the other one to measure speed and distance from the cycle crossroad. The results supported the hypothesis: the drivers turning right scanned the right leg of the T-intersection less frequently and later than those turning left. Thus, it appears that drivers develop a visual scanning strategy which concentrates on detection of more frequent and major dangers but ignores and may even mask visual information on less frequent dangers. The second part of the study evaluated different countermeasures, including speed humps, in terms of drivers' visual search behavior. The results suggested that speed-reducing countermeasures changed drivers' visual search patterns in favor of the cyclists coming from the right, presumably at least in part due to the fact that drivers were simply provided with more time to focus on each direction.
Article
Course holding by cyclists and moped riders includes both steering alongside a course and stabilising the vehicle. Inability to hold course may lead to conflicts with other road users. To design safe bicycle and moped facilities, and to consider the safety of those existing, knowledge about performance during course holding is necessary. Based on a literature survey, the article discusses how course holding will be influenced by characteristics of the course, the vehicle and the rider. Effects of disturbing factors such as side-wind and road-surface unevenness are also described. In a field study subjects carried out riding tests with various models of bicycles and mopeds on three courses. Speed, riding with one hand on the handlebars, side-wind and road-surface unevenness were included as independent variables. Results indicate that cyclists and moped riders need a width of at least 1 m on straight roads. At intersections this width should be at least 1.25 m. Performance in the tests also showed differences between vehicle models and modes of riding.
Article
Two experiments explored the extent to which induced blur, reduced luminance, and reduced visual fields affect drivers' steering performance in a driving simulator. In experiment 1, ten young participants (M = 21.2 years) drove at approximately 89 km/h (55 mph) along a curvy roadway while being exposed to blur (0 to + 10 D), luminance (0.003 to 16.7 cd/m), and visual field (1.7 and 150 degrees) manipulations. In experiment 2, a new group of ten young participants (M = 18.5 years) drove while exposed to seven visual field sizes (1.7 to 150 degrees). Steering was sensitive to a reduced field size but not to the blur and luminance challenges. Acuity, on the other hand, was sensitive to the blur and luminance challenges but not to reduced field size. In healthy young drivers, steering performance is remarkably robust to severe blur and to extremely low luminances. These results support a key element of the selective degradation hypothesis advanced by Leibowitz and colleagues--that steering abilities are preserved at night even when the ability to recognize objects and hazards is not. Additional research should address the other element of this hypothesis--that drivers fail to appreciate the extent to which their visual abilities are degraded at night.
Vademecum Fietsvoorzieningen (Standard for Bicylce Facilities) Flemish Government, Environment
  • Flemish
Flemish Government, 2012. Vademecum Fietsvoorzieningen (Standard for Bicylce Facilities). Flemish Government, Environment, Nature and Energy Department, Brussels
From Bicycle Crashes to Measures; Brief Overview of what we know and do not know (yet) Institute for Road Safety Research, Leidschedam. Van den Ouden
  • D A M Twisk
  • W P Vlakveld
  • A Dijkstra
  • M Reurings
  • W Wijnen
Twisk, D.A.M., Vlakveld, W.P., Dijkstra, A., Reurings, M., Wijnen, W., 2013. From Bicycle Crashes to Measures; Brief Overview of what we know and do not know (yet). Institute for Road Safety Research, Leidschedam. Van den Ouden, J.H., 2011. Inventory of Bicycle Motion for the Design of a Bicycle Simulator. Delft University of Technology, Delft, MSc thesis.
A conceptual framework for road safety and mobility applied to cycling safety. Accident Analysis and Prevention Visual requirements of vehicular guid-ance Human factors of visual and cognitive performance in driving Bicycle accidents and drivers' visual search at left and right turns
  • J P Schepers
  • M P Hagenzieker
  • R Methorst
  • Van Wee
  • G P Wegman
Schepers, J.P., Hagenzieker, M.P., Methorst, R., Van Wee, G.P., Wegman, F., 2013. A conceptual framework for road safety and mobility applied to cycling safety. Accident Analysis and Prevention, http://dx.doi.org/10.1016/j.aap.2013.03.032, In press. Schieber, F., Schlorholtz, B., McCall, R., 2008. Visual requirements of vehicular guid-ance. In: Castro, C. (Ed.), Human factors of visual and cognitive performance in driving. CRC Press, Boca Raton. Summala, H., Pasanen, E., Räsänen, M., Sievänen, J., 1996. Bicycle accidents and drivers' visual search at left and right turns. Accident Analysis and Prevention 28 (2), 147–153.
A prospective cohort study on minor accidents involving commuter cyclists in Belgium. Accident Analysis and Pre-vention 45
  • De Geus
  • B Vandenbulcke
  • G Int Panis
  • L Thomas
  • I Degraeuwe
  • B Cumps
  • E Aertsens
  • J Torfs
  • R Meeusen
De Geus, B., Vandenbulcke, G., Int Panis, L., Thomas, I., Degraeuwe, B., Cumps, E., Aertsens, J., Torfs, R., Meeusen, R., 2012. A prospective cohort study on minor accidents involving commuter cyclists in Belgium. Accident Analysis and Pre-vention 45, 683–693.