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Source publication
Recent research shows that braking of vehicles equipped with a front brake light is identified significantly earlier than braking of vehicles without front brake lights. Moreover, the absence of front brake lights leads to more conservative road crossing decisions. These results suggest that front brake lights are able to facilitate the pedestrians...
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A usual traffic calming measure (TCM) to reduce vehicle speed in urban areas is the traffic lights that turn red when a vehicle exceeds the speed limit. These traffic lights can detect if an approaching vehicle exceeds the speed limit and, if so, stop it by means of a red light. It is generally employed in interurban roads rather than in big cities...
Citations
... This research on the effects of the front brake light described in this article is the first to be conducted in real road traffic. However, non-public testing already occurred in 2017 at Berlin Tegel Airport [35]. A total of 102 airport vehicles (e.g., baggage vehicles, service cars, fuel trucks, passenger buses) were equipped with front brake lights. ...
This paper analyses the impact of a front brake light (FBL) on road safety from a pedestrian perspective. In addition to the traditional brake lights mounted at the rear of vehicles, an FBL can provide extra information about the driver’s intention to stop, especially to road users looking at the front of the approaching vehicle. This innovative feature aims to improve road safety by providing additional visual cues, where rear brake lights are not visible. Because pedestrians usually have a better line of sight to the front of a vehicle, the front brake light is more effective in alerting them to an impending stop. Therefore, an FBL could help them feel more confident when crossing the road by helping determine if it is safe to do so. A total of 621 questionnaires were collected from pedestrians who participated in the first real field test of FBL. The test period was conducted from November 2022 to September 2023 in two neighbouring regions of Slovakia. Their feedback allowed us to assess how the presence of an FBL influenced their perception of road safety, particularly when crossing roads. As a statistical result, more than 81% of the participants felt safer when crossing the road due to the presence of an FBL. Notably, the older generation evaluated FBLs very positively, while the youngest generation demonstrated more dangerous behaviour. Furthermore, the survey revealed that a significant proportion of respondents maintained a more reserved attitude towards the benefits of FBLs, largely due to a lack of information.
... For example, eHMIs have been shown to increase user acceptance and trust, their willingness to interact with the AVs, and improve understanding of AV's intentions (e.g. Böckle et al., 2017;Deb et al., 2018;Kooijman et al., 2019;Monzel et al., 2021;Petzoldt et al., 2018). Automated vehicles equipped with eHMIs are also shown to help pedestrians make quicker crossing decisions, thus saving time and improving overall traffic flow (e.g. ...
Objective
We investigated how different deceleration intentions (i.e. an automated vehicle either decelerated for leading traffic or yielded for pedestrians) and a novel (Slow Pulsing Light Band – SPLB) or familiar (Flashing Headlights – FH) external Human Machine Interface (eHMI) informed pedestrians’ crossing behaviour.
Background
The introduction of SAE Level 4 Automated Vehicles (AVs) has recently fuelled interest in new forms of explicit communication via eHMIs, to improve the interaction between AVs and surrounding road users. Before implementing these eHMIs, it is necessary to understand how pedestrians use them to inform their crossing decisions.
Method
Thirty participants took part in the study using a Head-Mounted Display. The independent variables were deceleration intentions and eHMI design. The percentage of crossings, collision frequency and crossing initiation time across trials were measured.
Results
Pedestrians were able to identify the intentions of a decelerating vehicle, using implicit cues, with more crossings made when the approaching vehicles were yielding to them. They were also more likely to cross when a familiar eHMI was presented, compared to a novel one or no eHMI, regardless of the vehicle’s intention. Finally, participants learned to take a more cautious approach as trials progressed, and not to base their decisions solely on the eHMI.
Conclusion
A familiar eHMI led to early crossings regardless of the vehicle’s intention but also led to a higher collision frequency than a novel eHMI.
Application
To achieve safe and acceptable interactions with AVs, it is important to provide eHMIs that are congruent with road users’ expectations.
... In recent years, there has been a marked increase in the variety and sophistication of eHMI concepts [17,63]. Initially, eHMIs echoed traditional vehicular signals: brake lights indicating deceleration [54,57], and marker lamps indicating the activation of an automated driving system [41]. Yet, technology and design advancements brought forth innovative and intuitive eHMI designs. ...
Policymakers advocate for the use of external Human-Machine Interfaces (eHMIs) to allow autonomous vehicles (AVs) to communicate their intentions or status. Nonetheless, scalability concerns in complex traffic scenarios arise, such as potentially increasing pedestrian cognitive load or conveying contradictory signals. Building upon precursory works, our study explores 'interconnected eHMIs, ' where multiple AV interfaces are interconnected to provide pedestrians with clear and unified information. In a virtual reality study (N=32), we assessed the effectiveness of this concept in improving pedestrian safety and their crossing experience. We compared these results against two conditions: no eHMIs and unconnected eHMIs. Results indicated interconnected eHMIs enhanced safety feelings and encouraged cautious crossings. However, certain design elements, such as the use of the colour red, led to confusion and discomfort. Prior knowledge slightly influenced perceptions of interconnected eHMIs, underscoring the need for refined user education. We conclude with practical implications and future eHMI design research directions.
... Regarding the subjective ratings (see RQ4), participants rated the FBL positively, as has previously been reported for adults (Eisele & Petzoldt, unpublished results ;Monzel et al., 2021;Petzoldt et al., 2018). Most participants indicated that it is a good idea, and it can increase their perception of safety. ...
... Since participants in the EC were informed about the function of an FBL, future research should examine potential effects of an FBL in cases where children do not receive any information about it. The design of an FBL and its effects should also be addressed in future studies, as this was not the focus of the present study, but there are several possible designs of an FBL that need to be considered, e.g., a green light (e.g., Monzel et al., 2021;Petzoldt et al., 2018). Within the scope of this study effects on children and adults were compared. ...
In this study, the effect of a frontal brake light (FBL) on children’s willingness to cross the road was investigated. While recent studies have investigated effects of an FBL their samples consisted exclusively of adults. The results and conclusions of these studies may not be applicable to children due to their partially less developed cognitive capabilities. Accordingly, the aim of this study was to investigate the effects of an FBL on children’s willingness to cross a vehicle’s path. In a mixed design simulation study, participants were assigned to an experimental condition (EC), in which vehicles were equipped with an FBL, or to a control condition (CC), in which vehicles were not equipped with an FBL. Children aged six to twelve watched videos from the perspective of a pedestrian standing at the curb. A vehicle with an initial speed of 30 km/h approached either by maintaining the speed or by decelerating. In the latter case, the braking onset was varied (55 m or 32 m from the pedestrian’s position). Participants’ task was to indicate their willingness to cross
the road in front of the vehicle at five different distances. Results show that FBL affected the willingness to cross the road, especially at an early braking onset (i.e., 55 m). If the vehicle decelerated (i.e., the FBL was activated in the EC), the willingness was significantly higher in the EC than in the CC. In case the vehicle maintained its speed (i.e., the FBL was not activated in the EC), the opposite effect appeared. However, children did not exclusively rely on information gained by the FBL, but still paid attention to distance to the vehicle and braking onset. In conclusion, the effects of an FBL on children are similar to the effects on adults identified in prior studies. Nevertheless, more research in complex scenarios is needed to draw general conclusions about the impact of FBL on road safety in differently aged children and adults.
... In terms of usability, while pedestrians were generally positive about the experience of using acceleration signal light, they still had doubts about their future application. In summary, acceleration signal light have significant advantages in clearly communicating vehicle information, enhancing pedestrian-vehicle interactions and improving road safety and can continue to be optimized to increase the likelihood of realistic applications and provide a new solution for improving urban road safety 39 . ...
The number of casualties resulting from collisions between pedestrians and motor vehicles continues to rise. A significant factor is the misunderstanding of vehicle behavior intentions by pedestrians. This is especially true with the continuous development of vehicle automation technology, which has reduced direct interaction between drivers and the outside world. Therefore, accurate communication of vehicle behavior intentions is becoming increasingly important. The purpose of this study is to investigate the impact of external vehicle acceleration signal light on the interaction experience between pedestrians and vehicles. The differences between the use and nonuse of acceleration signal light are compared through controlled test track experiments in real scenarios and in videos.The results show that acceleration signal light help pedestrians understand vehicle behavior intentions more quickly and make safer crossing decisions as well as improving their perception of safety when crossing the street and their trust in vehicle behavior.
... A limitation of our study was that it was conducted in a safe lab environment. The impacts of eHMIs on the safety of pedestrians in real-life scenarios, and the potential for eHMIs to reduce the number of road traffic accidents is still an understudied topic that requires more research (see Cefkin et al., 2019;Forke et al., 2021;Merat et al., 2018;Monzel et al., 2021; for studies on the effect of eHMIs in naturalistic environments). It must also be acknowledged that the installation of eHMIs is associated with additional costs, a factor that cannot be overlooked in the broader scope of this research. ...
Automated vehicles need to prioritize pedestrian safety. One way to achieve this is through external human-machine interfaces (eHMIs) that send visual signals to pedestrians. To date, limited research has systematically investigated text-based eHMIs and light-based eHMIs with regard to eye movements and attention allocation. The present study addressed this gap by using a gaze-contingent paradigm to test the hypothesis that eHMIs requiring foveal attention, such as text-based eHMIs, result in longer response times compared to eHMIs that can be understood from peripheral vision, such as flashing lights. In this study, 23 participants viewed non-interactive animated video clips depicting a traffic situation of automated vehicles with no eHMI, a flashing-light eHMI, or a textual eHMI, while eye movements were recorded using an eye tracker. Participants were instructed to press the spacebar whenever they deemed it safe to cross the road. The results showed that response times were faster when the eHMI was present, with no significant difference between the two eHMI types. An analysis of gaze dispersion further suggested that the Flash eHMI captured attention relatively briefly, while the Text eHMI held attention somewhat longer, followed by no eHMI where participants focused on the approaching vehicle the longest. The gaze-contingent window caused a reduction in the number of saccades and a slowing of response times. In conclusion, the negative effect of the gaze-contingent window on response times and saccades highlights the importance of considering peripheral vision in the design of eHMIs for pedestrian safety.
... A limitation of our study was that it was conducted in a safe lab environment. The impacts of eHMIs on the safety of pedestrians in real-life scenarios, and the potential for eHMIs to reduce the number of road traffic accidents is still an understudied topic that requires more research (see Cefkin et al., 2019;Forke et al., 2021;Merat et al., 2018;Monzel et al., 2021; for studies on the effect of eHMIs in naturalistic environments). It must also be acknowledged that the installation of eHMIs is associated with additional costs, a factor that cannot be overlooked in the broader scope of this research. ...
Automated vehicles need to prioritize pedestrian safety. One way to achieve this is through external human-machine interfaces (eHMIs) that send visual signals to pedestrians. eHMIs can be either text-based or light-based. However, there has been limited research on the effects of these types of eHMI on human information processing and attention allocation. This study aimed to fill this gap by using a gaze-contingent approach, which blurs the view outside a circular aperture, to test the hypothesis that text-based eHMIs, which require focused or foveal attention, result in longer response times compared to light-based eHMIs, which can be understood using peripheral vision. In this study, 23 participants watched animated video clips of traffic situations involving automated vehicles with either no eHMI, a flashing-light eHMI, or a text-based eHMI. Their eye movements were tracked, and they were asked to press the spacebar when they felt it was safe to cross the road. The results showed faster response times when an eHMI was present, with no significant difference between the two types of eHMIs. Further analysis suggested that the flashing-light eHMI captured attention briefly, while the text-based eHMI held attention for a longer period. When no eHMI was present, participants focused on the approaching vehicle for the longest time. The gaze-contingent window resulted in fewer eye movements and slower response times. In conclusion, the study showed that the gaze-contingent window negatively affected response times and eye movements, emphasizing the importance of considering peripheral vision when designing eHMIs for pedestrian safety.
... The Institute for Legal and Traffic Psychology in Bonn conducted a pre-study on the front brake light in a non-public space at Berlin Tegel Airport. Further information on the results of this study can be found in Monzel et al. [55]. As of 2023, the University of Žilina continues its research on real traffic in the Zilina and Trencín regions of Slovakia. ...
The aim of innovations in road safety is to contribute to the better protection of road users and to minimize damage to their property. The main objective of this article is to identify disparities in perceptions of a front braking light by examining the road safety of road users based on their type of employment and the number of kilometers driven per year. The research will evaluate the attitudes of selected groups of road users based on the number of kilometers driven in a calendar year and whether driving a motor vehicle is their main duty as part of their job. The analysis involved 239 respondents using a paper questionnaire. Disparities in perceptions of innovations, with regard to road safety, were evaluated using contingency tables, chi-square tests, non-parametric tests, and Cramer’s V. Road users feel much safer with a front braking light when crossing traffic comprising vehicles and pedestrians (71%), at pedestrian crossings (74%), when turning left (63.4%), as well as when crossing traffic comprising multiple vehicles (62.5%). Disparities between respondents based on the type of employment of the road user were not confirmed. Road users with a higher number of driven kilometers have a more positive perception of the front braking light at pedestrian crossings.
... The innovation of the front brake light provides other road users with information about the braking of the vehicle. The front brake light is technically a green light [52] located at the front of the vehicle (Fig. 1). The innovation of the front brake light provides other road users with information about the braking of the vehicle. ...
... The innovation of the front brake light provides other road users with information about the braking of the vehicle. The front brake light is technically a green light [52] located at the front of the vehicle (Fig. 1). The choice of green color is due to the fact that there are certain colors of light that cannot be used, such as red light for the rear brake light, blue light for indicating priority of passage, and orange light for indicating the direction of travel of the vehicle. ...
... The questionnaire was created in collaboration between the University of Žilina and the Institute for Legal and Traffic Psychology in Bonn, which conducted a pre-study on the front brake light in a non-public space at Berlin Tegel Airport. Further information on the results of this study can be found in Monzel et al. [52]. In 2023, the University of Žilina continues the research in real traffic in the Žilina and Trenčín regions of Slovakia. ...
The aim of innovations in road safety is to contribute to better protection of road users and to minimize damage to their property. The main objective of the article is to identify disparities in the perception of an innovation element in road safety by road users based on their type of employment and the number of kilometers driven per year. The research will evaluate the attitudes of selected groups of road users based on the number of kilometers driven in a calendar year and whether driving a motor vehicle is their main job duty. The analysis involved 239 respondents using a paper questionnaire. Disparities in the perception of innovations in road safety were evaluated using contingency tables, chi-square tests, non-parametric tests, and Cramer's V. Road users feel much safer with a front braking light when crossing traffic of vehicles and pedestrians (71%); at pedestrian crossings (74%); when turning left (63.4%); as well as when crossing traffic of multiple vehicles (62.5%). Disparities among respondents based on the type of employment of the road user were not confirmed. Conversely, road users with a higher number of kilometers driven per year have a more positive perception of the innovation element at pedestrian crossings.
... According to [6,15], cyclists on electric bicycles are particularly dangerous. Children and the elderly may have difficulty estimating the distance and especially estimating the speed or deceleration of an approaching vehicle [1,10]. ...
The European Union has an ambition to achieve zero road deaths by 2050. It is an ambitious target, but not an unachievable one. The installation of a front brake light, which provides information to other road users that the vehicle is braking, can help to achieve this goal. Today, this information is available to road users who can see the rear of the vehicle. Because the brake lights are located at the rear of the vehicle. The information that the vehicle is braking is also important when looking at the front of the vehicle. Whether it is other drivers or other road users such as pedestrians and cyclists. The aim of this paper is to conduct a research among professional road transport drivers what their opinion is about the front brake light. From their opinion, we will conclude whether such light has the potential to improve road safety or not.
