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• We investigated cyclists' perceived safety at different junction designs using a bicycle simulator and guideline-based interviews. • Protected intersection design provided highest level of perceived safety. • Participants' overall assessment consist of statements concerning perceived safety, comprehensibility, and comfort. Introduction : Although cycling provides both individual and societal benefits, the mode share in Germany remains at a relatively low level. One reason described in literature is the lack of perceived safety due to the cycling infrastructure, especially at junctions. The study addresses the influence of junction design on cyclists' perceived safety. Method: Three intersections (BS: Berlin Standard, PI: protected intersection, CbC: cycle lanes between car lanes) and one roundabout were modeled in a virtual environment. Using a bicycle simulator, n = 46 participants cycled through each junction design, followed by a qualitative interview. We conducted a structured content analysis on the interview transcripts. Results: Regarding the quality of statements, PI provides the highest level of perceived safety whereas CbC provides the lowest level. Both roundabout and BS provide medium to low perceived safety. Specific design features, such as continuous cycling infrastructure, physical separation and elements enhancing cyclists' visibility improve participants' perceived safety. On the other hand, curbs, bends, and elements obstructing visibility decrease perceived safety. Our findings also point towards a difference between overextending and manageable interactions between cars and cyclists. While manageable interactions raise attention to an appropriate extent, overextending interactions diminish the quality of the cycling experience so that some cyclists rather violate rules instead of using the designated cycling infrastructure. Furthermore, three factors influence participants' perception of infrastructure design: comprehensibility, comfort, and perceived safety. Conclusions: To provide a cycling friendly infrastructure, planners should consider cyclists' perceived safety as well as comfort and comprehensibility. Furthermore, in contrast to isolated segments, a continuous high-quality cycling infrastructure network should be implemented. Lastly, infrastructure might focus on manageable interactions rather than cause overextending interactions. Practical Application: The findings should be considered in future cycling infrastructure planning. Planners may test and modify temporary solutions to find appropriate designs for each junction. [ABSTRACT FROM AUTHOR]

Virtual reality (VR) offers an interactive and more engaging setting for studying hazard anticipation and anticipation in child cyclists who have a considerably higher risk for being involved in a traffic accident. Yet, reliability, validity and usability of VR for scientific purposes remain poorly documented. With the long-term goal in mind of developing fun and interactive training programmes, this study intends to test the effectiveness of a novel VR tool to promote cycling safety in children. A virtual traffic environment that reflects a typical Belgian city was created in Unity3D. Children (n = 130; 11.37 ± 0.54 years old; 92 girls and 38 boys), equipped with a HTC Vive, cycled on an instrumented bicycle through the virtual environment (VE) in which they had to negotiate 14 hazards in a safe manner. Participants' speed and braking responses for the hazards were reported, while eye movements were recorded by means of the Pupil Labs eye tracking VR add-ons. Following the hazard anticipation test, children were questioned regarding perceived realism, simulator sickness and risky behaviours. After 4 weeks, 15 children performed the VR hazard anticipation test a second time. With respect to validity of the VR simulator, the results demonstrate that the overt hazards were fixated (p = 0.044) and braked for (p < 0.001) more, and fixated (p < 0.001) and braked for earlier (p < 0.001) compared to the covert hazards, which provides evidence for content validity of the VR simulator. The (weak) association between temperamental traits such as "errors and violations" and speed supports convergent validity. Furthermore, participants rated the VE as realistic to highly realistic which reflects face validity. Intraclass correlations suggest moderate test–retest reliability for all variables except first fixation rate. To improve ecological validity of hazard anticipation testing in cyclists, this study allowed the participants to cycle and fully interact with the VE. We found that the simulator provides a fun and realistic tool to document hazard anticipation skills in child bicyclists. [ABSTRACT FROM AUTHOR]

Cyclists are one of the main categories of road users particularly exposed to accident risk. The increasing use of this ecological means of transport requires a specific assessment of cyclist safety in terms of traffic flow and human factors. In this study, a particular visual tracking tool has been used to highlight not only the main critical points of the infrastructure, where a high level of distraction is recorded, but also the various interactions with different road users (pedestrians, vehicles, buses, wheelchairs, cyclists). To confirm the critical aspects of the infrastructure and the trend of workload, a similar circuit was reproduced in a bicycle simulator, which also allowed a meaningful comparison of cycling behaviour. The innovative component of this paper is a comparison between a real test, held in Stockholm, and a simulator where the same scenario has been represented, in order to highlight the objective differences in behaviour. The cycling performance was also evaluated both from an objective point of view, with the count of frames related to each category of visualization, and from a subjective one, through the questionnaires. The results show the crossing as a critical aspect because only 4/3% fixation is required for both simulated and real tests to confirm the significance of the comparison between the two experiments. The high attention rate, resulting from frame-by-frame analysis, also points to a clear difference in the perception of users, who feel with a low workload. [ABSTRACT FROM AUTHOR]

This study investigated the impact of two road treatments on cyclist behaviour using an bicycle simulator. The treatments were sharrows (presence or absence) at a roundabout and widening an on-road bike lane (width 1.2 m or 1.8 m) on a curved mid-block section of the road. Outcomes collected included count (e.g. number of lane excursions) and continuous responses (lane position upon entry into the roundabout, in metres from the curb). A convenience sample of 21 Perth-based participants was recruited between 1 July and 30 September 2021. The results found that the presence of sharrows was not significantly associated with the distance from the left curb when entering a single lane roundabout. However, females rode 0.44 m further from the left curb when entering the roundabout than males, which was significant (95 % CI = 0.02–0.85; p = 0.04). Riders, aged 26–40 years, also rode 0.61 m further from the left curb when entering the roundabout than riders aged 18–25 years, which was also significant (95 % CI = 0.18–1.05; p = 0.01). The rate of bike lane excursions significantly decreased by 68 % for the wide bike lane on the curved mid-block section of the road compared to the standard width bike lane (IRR = 0.32; 95 % CI = 0.11–0.88; p = 0.03). Riders, aged 26–40 years, had a significant increased rate of 8.72 excursions than riders aged 18–25 years (IRR = 8.72; 95 % CI = 3.32–22.89; p

With the undeniable advance of automated vehicles and their gradual integration in day-today urban traffic, many new technologies have been developed that offer great potential for this emerging field of research. However, testing automated vehicle technologies in real road traffic with vulnerable road users (VRUs) is still a complicated and time consuming procedure. The virtual development and evaluation of automated vehicles using simulation tools offers a good opportunity to test new functions efficiently. However, existing models prove to be insufficient in modeling the interaction between autonomous vehicles and vulnerable road users such as bicyclists and pedestrians. In this paper, an automated vehicle model for microscopic traffic simulation tools is developed with the open-source traffic simulation software Simulation of Urban Mobility (SUMO) and evaluated in common traffic interaction scenarios with bicyclists. A controller model is proposed using different path-finding algorithms from the field of robotic and automated vehicle research, which covers all important control levels of a self-driving vehicle. Finally, its performance is compared to existing car-following and lane-changing models. Results showcase that the autonomous vehicle model achieves either comparable results or has a much steadier and more realistic driving behavior when compared to existing driving models while interacting with bicyclists. The whole source code developed over the course of this work is freely accessible at: https://github.com/FlixFix/Kimarite.

To achieve the 1.5-degree target of the Paris Climate Agreement, it is of great importance to promote environmentally friendly means of transport. In urban areas, shifting motorized trips to active transport modes (i.e., walking and cycling) is essential. Therefore, knowledge of walking and cycling is indispensable for planning and policy, which is the basis for targeted promotion of active forms of mobility. This paper aims to identify factors that specifically influence cycling and to derive recommendations for action for planning and policy in a virtual testbed. Specifically, the influence of traffic planning measures (i.e., structural infrastructure facilities for stationary and moving traffic as well as traffic regulations) and urban design measures (i.e., the design of public space) on the promotion of cycling will be shown. For this purpose, a virtual reality simulation was used, independent of different external conditions during field surveys and the necessity of time-, cost- and regulation-intensive structural changes. Using an improved bicycle simulator, 93 people cycled through 20 variations of an approximately 680 m long road section, surveying the effect of selected traffic planning and urban design parameters. Special attention was paid to the subjective safety of the cyclists and the attractiveness of the urban environment. Furthermore, three types of infrastructure were differentiated: No bicycle infrastructure (riding on the roadway), a bicycle lane, and a structurally separated cycle path next to the sidewalk. The virtual road section represented a real location. In addition to the findings gained from the physiological optimization of the simulator, the results show that roadside greenery had the highest effectiveness in terms of subjective safety and attractiveness. Other factors with a high influence were a speed reduction from 50 to 30 km/h when riding on the roadway with cars and the red coloring of the bicycle lane, each increasing the perception of safety. In contrast, a lack of a boundary line between the cycle path and the sidewalk was unsettling for those who rarely or never ride bicycles in their daily lives. In addition, restaurant and recreation areas increased the attractiveness of the road section, although entailing a lower perception of safety. Other factors, such as motor vehicle traffic volume or vehicles parked at the roadside, showed no significant effects on the evaluation of cycling.With the help of these findings, the consequences of traffic planning and urban design measures can be better assessed in subsequent virtual testbeds. Also, initial trends can be identified as to which planning instruments should be used as a priority to promote cycling in urban areas. Future work should validate the transfer of these insights into physical urban spaces to support further the mid-term transformation towards sustainable urban mobility using scientific evidence.

Cyclists are one of the main categories of road users particularly exposed to accident risk. The increasing use of this ecological means of transport requires a specific assessment of cyclist safety in terms of traffic flow and human factors. In this study, a particular visual tracking tool has been used to highlight not only the main critical points of the infrastructure, where a high level of distraction is recorded, but also the various interactions with different road users (pedestrians, vehicles, buses, wheelchairs, cyclists). To confirm the critical aspects of the infrastructure and the trend of workload, a similar circuit was reproduced in a bicycle simulator, which also allowed a meaningful comparison of cycling behaviour. The innovative component of this paper is a comparison between a real test, held in Stockholm, and a simulator where the same scenario has been represented, in order to highlight the objective differences in behaviour. The cycling performance was also evaluated both from an objective point of view, with the count of frames related to each category of visualization, and from a subjective one, through the questionnaires. The results show the crossing as a critical aspect because only 4/3% fixation is required for both simulated and real tests to confirm the significance of the comparison between the two experiments. The high attention rate, resulting from frame-by-frame analysis, also points to a clear difference in the perception of users, who feel with a low workload.

In this paper, we present the new features implemented on the bicycle simulator developed by the Perceptions, Interactions, Behaviors and Simulations Lab for road and street users (PICS-L) at Gustave Eiffel University. The added features were deemed necessary to study road-bicycle interactions. We equipped the simulator platform with: three actuators to render the road profile vibrations, an asphalt specimen attached to the rear tire to render the road adhesion, and a new virtual reality environment to render a part of the city of Vanves in France. Simultaneously, we developed a mathematical model with 6 degrees of freedom including the three rotational angles (Yaw, Pitch and Roll) and their influence on vertical, lateral and longitudinal modeling. In order to validate the simulator and the developed model physically and subjectively, we conducted an experiment involving 36 participants who rode the simulator for around 600 meters with full control on the handlebar, pedals and brakes. The improved simulator/mathematical model will be employed to further study bicycle dynamics, cyclist behavior and the interaction with the infrastructure and other road users.

• Bicycling simulator used to determine cyclist's behavior and GSR responses. • GSR response was 1.77 peaks per minute more in the no bike lane condition. • GSR response was affected by vehicular volume, but not vehicular speed. • Females were less comfortable riding in both no bike lane and bike lane conditions. • Methodology has potential to evaluate wide range of facilities and types of riders. Population growth increase of vehicle ownership, and development patterns have resulted in greater levels of congestion, pollution, and crash frequency. A proposed solution to lessen current transportation system demands is to increase the share of bicycle trips. Furthermore, as cycling is perceived by some as both a dangerous and stressful mode of transportation, understanding the factors that lead to less comfortable and stressful riding, can help drive bicycle infrastructure development. To establish a more robust understanding of the behaviors of bicyclists and how infrastructure design and operations influence them, a bicycle simulator was used to evaluate bicyclist performance measures of velocity, horizontal displacement, and physiological responses (i.e., galvanic skin response) while riding in varying roadway conditions. Results showed that bicyclists in the bike lane condition, had a GSR reading 1.77 peaks per min less than when cycling in the no bike lane condition. When bicyclists were in no bike lane condition, the GSR reading was not affected by vehicle speed but it was affected by the vehicular volume. Additionally, females felt less comfortable when riding in either bike condition, even though they reported that they were "Strong and Fearless" riders. The methodology used for this study sets forth the foundation for future research that could evaluate varying facility designs and a wider range of individuals. [ABSTRACT FROM AUTHOR]

This work presents SimBike, a virtual bicycle simulator that uses non-conventional motor, sensory and sensorimotor devices to provide greater user involvement and comfort. SimBike aims to recreate the activity of riding a bicycle by exploring possibilities of electronic devices, such as making curves with the handlebar or body-weight, pedaling, braking, among others. It also offers feedback commonly expected by the rider, such as wind sensation varying according to speed and the sensation of trepidation on uneven terrain. The simulator was evaluated with 16 users, obtaining positive results regarding user experience, comfort, and immersion. As future work, we propose to improve some features to adapt the simulator for all users, regardless of their weight and height.

• Max CVLZ outperformed Min CVLZ and no CVLZ. • In the no CVLZ scenario, 1/3 of cyclists used the sidewalk over the travel lane. • Min CVLZ and the courier on the side negatively influenced cyclists' performance. • Extra buffer for the courier improves bicyclist performance measures positively. • Accessories behind the truck did not change the performance of cyclists. With growing freight operations within the United States, there continues to be a push for urban streets to accommodate trucks during loading and unloading operations. Currently, many urban locations do not provide loading and unloading zones, which results in trucks parking in places that can obstruct roadway infrastructure designated to vulnerable road users (e.g., pedestrians and cyclists). In an effort to understand the implications of these truck operations, a bicycle simulation experiment was designed to evaluate the impact of commercial vehicle loading and unloading activities on safe and efficient bicycle operations in a shared urban roadway environment. A counter-balanced, factorial design was chosen to explore three independent variables: commercial vehicle loading zone (CVLZ) sizes with three levels (no CVLZ, Min CVLZ, and Max CVLZ), courier position with also three levels (No courier, behind the truck, beside the truck), and loading accessories (Acc) with two levels (no Acc, and with Acc). Cyclist's velocity and lateral position were used as performance measures. Data were obtained from 48 participants (24 women) resulting in 864 observations in 18 experimental scenarios. Linear Mixed-Effects Models (LMM) were developed to examine the effect of each independent variable level on bicyclist performance. Results from LMM model suggest that loading zone size had the greatest effect on cyclist's divergence. Additionally, when the courier was walking beside the truck, cyclist's velocity significantly dropped to almost one m/sec in compared when the courier located behind the truck. The presence of accessories had the lowest influence on both velocity and lateral positions of cyclists. In the no CVLZ scenarios, the delivery vehicle was parked at the bike lane, therefore; cyclists had to choose between using the travel lane or the sidewalk. About one-third of participants decided to use the sidewalk. These findings could support better roadway and CVLZ design guidelines, which will allow our urban street system to operate more efficiently, safely, and reliably for all users. [ABSTRACT FROM AUTHOR]

• A VR bicycle simulator that motion-captures bicycle and body movements was developed. • Crossing behavior and tracing behavior of cyclists were measured and analyzed. • The crash rate for the older riders was 5.3 times higher than that for younger riders. • Slow switching to entry and variation in crossing routes are crash-inducing risks. • Specific actions of riders leading to collision accidents are quantified. In 2021, 69 % of those who died in Japan while riding a bicycle were of an older age. Preventing such accidents is an important issue because older bicyclists are more likely to be fatally injured in an accident. We developed a bicycle simulator that can safely simulate dangerous traffic environments by combining VR technology, motion capture technology, and various sensors to investigate the driving behavior of bicyclists who are involved in accidents. The simulator measures operating data such as floor reaction force, wheel rotation angle, brake lever displacement, position and posture of motion capture devices, and position and posture of the bicycle and vehicles at 60 Hz. We projected images of the virtual traffic environment to reflect the driving behavior in real-time onto three screens installed at the front, right side, and rear of the bicycle using three projectors. The constructed simulator was implemented for a "crossing inspection" where a rider checks for safety in front and behind while riding down a straight road with one lane and crossing this roadway and compared this to a "tracing inspection" where a model route is traced using a previously measured safe route taken by a younger rider. We measured and analyzed the bicyclist behaviors of nine younger and six older participants during two types of inspections as a usability study. In the crossing inspection, the crash rate for the older riders in the near lane was 5.3 times higher than that for the young. Riders collided with vehicles exhibited minimal rearward checking angles before entering a roadway, extended durations from the end of the last rearward check to roadway entry, and considerable standard deviations during road crossings. Moreover, in the tracing inspection, younger participants demonstrated superior trajectory passage rates and maintained closer proximity to the model, whereas older participants manifested diminished trajectory passage rates and remained at more extended distances from the model. Notably, a declining trajectory passage rate corresponded to an increase in the standard deviation of the crossing route and the time taken to enter the roadway. [ABSTRACT FROM AUTHOR]

In Australia, the proportion of serious and fatal road traffic injuries involving cyclists is increasing and it is recognised that there is a growing need to improve cyclist safety to encourage increased participation in this sustainable mode of transport. Relatively little research has been conducted in Australia to understand how cyclist behaviour can be influenced through variations in road design aimed to improve safety. This paper presents the findings from a study using a newly developed virtual reality bicycle simulator. The study examined how bicycle lane width and perceptual countermeasures can influence cyclist speed and position. Twenty seven participants ranging in age 18 to 39 years (M=24.2, SD=5.7) participated in the study. A statistically significant main effect was observed for the influence of bicycle lane width on cyclist lateral position. Post-hoc testing found that cyclist position was significantly different between each lane width iteration indicating that cyclist lateral position within the bicycle lane is influenced by the available width of the bicycle lane. Statistically significant differences were also identified between participant's position and variation in lateral position across five different perceptual countermeasure configurations. The findings of this study provide fundamental information about how cyclists choose to position themselves when riding in bicycle lanes in a validated virtual reality environment. The findings illustrate that, regardless of the width of the bicycle lane, cyclists tend to ride towards the centre of the lane and the study illustrated that use of perceptual countermeasures can be an effective measure to encourage cyclists to adopt safer cycling positions. The implications of these findings for enhanced road design to improve cyclist safety are discussed. [ABSTRACT FROM AUTHOR]

The study’s aim was to assess the behavioural validity of participants using of a newly developed bicycle simulator with respect to a range of cycling performance measures collected both using the cycling simulator and on-road. The validation study consisted of a within-subjects study design comparing participants riding on-road with riding in the simulator. The study recruited 26 participants ranging in age from 18 to 35 years (M = 25.0, SD = 4.8). Absolute validity was established for measures of spatial positioning including average lane position, deviation in lane position and average passing distance from kerbside parked cars. Relative validity was established for the average speed of cyclists and their speed reduction on approach to intersections and a degree of validity was established for aspects of the participants head movements on approach to intersections. The study found evidence to suggest that aspects of cyclist behaviour can be investigated using the bicycle simulator, however further validation research may be required in order to more comprehensively validate looking behaviours, more complex performance measures and for a wider age range of cyclists. [ABSTRACT FROM AUTHOR]

This paper presents a novel approach to modelling visual distraction of bicyclists. A unique bicycle simulator equipped with sensors capable of capturing the behaviour of the bicyclist is presented. While cycling two similar scenario routes, once while simultaneously interacting with an electronic device and once without any electronic device, statistics of the measured speed, head movements, steering angle and bicycle road position along with questionnaire data are captured. These variables are used to model the self-assessed distraction level of the bicyclist. Data mining techniques based on random forests, support vector machines and neural networks are evaluated for the modelling task. Out of the total 71 measured variables a variable selection procedure based on random forests is able to select a fraction of those and consequently improving the modelling performance. By combining the random forest-based variable selection and support vector machine-based modelling technique the best overall performance is achieved. The method shows that with a few observable variables it is possible to use machine learning to model, and thus predict, the distraction level of a bicyclist. [ABSTRACT FROM AUTHOR]

Detailed specifications of urban traffic from different perspectives and scales are crucial for understanding and predicting traffic situations from the view of an autonomous vehicle (AV). We suggest a data-driven specification scheme for maneuvers at different design elements of the built infrastructure and focus on urban roundabouts in Germany. Based on real observations, we define classes of maneuvers, interactions and driving strategies for cyclists, pedestrians and motorized vehicles and define a matrix for merging different maneuvers, resulting in more complex interactions. The sequences of these interactions, which partially consist of explicit communications, are extracted from real observations and adapted into microscopic traffic flow simulations. The simulated maneuver sequences are then visualized in 3D environments and experienced by bicycle simulator test subjects. Using trajectory segments (in fictional space) from two conducted simulator studies, we relate the recorded movement patterns of test subjects with observed cyclists in reality. [ABSTRACT FROM AUTHOR]

Car-following models are used in microscopic simulation tools to calculate the longitudinal acceleration of a vehicle based on the speed and position of a leading vehicle in the same lane. Bicycle traffic is usually included in microscopic traffic simulations by adjusting and calibrating behavior models developed for motor vehicle traffic. However, very little work has been carried out to examine the following behavior of bicyclists, calibrate following models to fit this observed behavior, and determine the validity of these calibrated models. In this paper, microscopic trajectory data collected in a bicycle simulator study are used to estimate the following parameters of the psycho-physical Wiedemann 99 car-following model implemented in PTV Vissim. The Wiedemann 99 model is selected due to the larger number of assessable parameters and the greater possibility to calibrate the model to fit observed behavior. The calibrated model is validated using the indicator average queue dissipation time at a traffic light on the facilities ranging in width between 1.5 m to 2.5 m. Results show that the parameter set derived from the microscopic trajectory data creates more realistic simulated bicycle traffic than a suggested parameter set. However, it was not possible to achieve the large variation in average queue dissipation times that was observed in the field with either of the tested parameter sets. [ABSTRACT FROM AUTHOR]

• Bicyclists' perceived safety was studied in an immersive virtual reality experiment. • Participants bicycled through five different environments with a bicycle simulator. • Participants felt safer when riding in the segregated bicycle path. • General findings were in agreement with previous research using classic methods. • Immersive virtual reality is a valuable tool to evaluate future street designs. There is a need for methods that provide a better understanding of bicyclists' perceived safety and preferences on currently unavailable and/or unknown bicycle facilities. Different survey methods have been used to study bicyclists' behavior, experiences, and preferences; ranging from verbally described facilities to surveys including images and videos. Virtual Reality (VR) experiments blur the boundaries between stated preference (SP) surveys and revealed preference (RP) surveys and provide a realistic sense of design. This research introduces a novel research method in bicycling research and discusses the results of an experiment using a bicycle simulator combined with immersive VR. In total, 150 participants participated in this experiment and were asked about demographics and perceptions and preferences after bicycling in five different environments with an instrumented bicycle in VR. A 5 × 2 mixed design was used with bicycling environment as within-subject factor and pedestrian / traffic volume as between-subject factor. ANOVA tests revealed how each environment and ambient pedestrian / traffic volume affected perceived level of safety (PLOS) and willingness to bicycle (WTB). Pairwise comparison showed that participants felt safer bicycling on the segregated bicycle path compared to bicycling on the painted bicycle path on the road and roadside. There was no meaningful difference between WTB for less than 10 min and WTB for more than 10 min between bicycling on a painted bicycle path on the sidewalk and painted bicycle path on the road. PLOS and WTB ratings of men and women were not significantly different from each other. The older segment of the sample was more worried about roadside bicycling and bicycle commuters were more confident to ride on the roadside. Despite having several limitations, immersive 360-degree VR was found a powerful presentation tool to evaluate future street designs which can inform transport and urban planning. [ABSTRACT FROM AUTHOR]

The study's aim was to assess the behavioural validity of participants using of a newly developed bicycle simulator with respect to a range of cycling performance measures collected both using the cycling simulator and on-road. The validation study consisted of a within-subjects study design comparing participants riding on-road with riding in the simulator. The study recruited 26 participants ranging in age from 18 to 35 years (M=25.0, SD=4.8). Absolute validity was established for measures of spatial positioning including average lane position, deviation in lane position and average passing distance from kerbside parked cars. Relative validity was established for the average speed of cyclists and their speed reduction on approach to intersections and a degree of validity was established for aspects of the participants head movements on approach to intersections. The study found evidence to suggest that aspects of cyclist behaviour can be investigated using the bicycle simulator, however further validation research may be required in order to more comprehensively validate looking behaviours, more complex performance measures and for a wider age range of cyclists., (Copyright © 2017 Elsevier Ltd. All rights reserved.)