Improving car drivers' perception of motorcycle motion through innovative headlight configurations

Following car reduces motorcycles' size-arrival effect: A study using online experiments

Many fatal motorcycle accidents occur because car drivers infringe on motorcycle riders' right-of-way. The size-arrival effect refers to observers' tendency to judge larger objects as arriving sooner than smaller objects when estimating an approaching object's arrival time, which is one cause of right-of-way motorcycle accidents. Previous research has focused on a single vehicle that approaches the driver. However, it is also possible that a motorcycle approaches a driver along with other vehicles driving on multiple-lane roads. This paper presents the results of two online experiments; Experiment 1 validated the size-arrival effect when either a car or a motorcycle approached a driver waiting to turn across an intersection; and Experiment 2 investigated the size-arrival effect when a motorcycle and a parallelly driven car simultaneously approached the driver. Participants (n = 1723) in Experiment 1 and (n = 986) in Experiment 2 took part in the study. The results (1) validated the size-arrival effect; drivers accepted a smaller gap for approaching motorcycles than cars; (2) in the present settings drivers made turn decisions based on the distance gap rather than the time-to-arrival gap; (3) driver's acceptance of the gap when facing a motorcycle and a car was comparable to when facing only the car and significantly larger than facing only a motorcycle. These findings indicate that a car driving parallelly or behind a motorcycle reduces the size-arrival effect. These findings provide implications to suggest a safe riding strategy for motorcycle riders. We also suggest that such online experiments would facilitate studying large samples with less effort.

A Comprehensive Review on the Behaviour of Motorcyclists: Motivations, Issues, Challenges, Substantial Analysis and Recommendations

With the continuous emergence of new technologies and the adaptation of smart systems in transportation, motorcyclist driving behaviour plays an important role in the transition towards intelligent transportation systems (ITS). Studying motorcyclist driving behaviour requires accurate models with accurate and complete datasets for better road safety and traffic management. As accuracy is needed in modelling, motorcyclist driving behaviour analyses can be performed using sensors that collect driving behaviour characteristics during real-time experiments. This review article systematically investigates the literature on motorcyclist driving behaviour to present many findings related to the issues, problems, challenges, and research gaps that have existed over the last 10 years (2011-2021). A number of digital databases (i.e., IEEE Xplore®, ScienceDirect, Scopus, and Web of Science) were searched and explored to collect reliable peer-reviewed articles. Out of the 2214 collected articles, only 174 articles formed the final set of articles used in the analysis of the motorcyclist research area. The filtration process consisted of two stages that were implemented on the collected articles. Inclusion criteria were the core of the first stage of the filtration process keeping articles only if they were a study or review written in English or were articles that mainly incorporated the driving style of motorcyclists. The second phase of the filtration process is based on more rules for article inclusion. The criteria of inclusion for the second phase of filtration examined the deployment of motorcyclist driver behaviour characterisation procedures using a real-time-based data acquisition system (DAS) or a questionnaire. The final number of articles was divided into three main groups: reviews (7/174), experimental studies (41/174), and social studies-based articles (126/174). This taxonomy of the literature was developed to group the literature into articles with similar types of experimental conditions. Recommendation topics are also presented to enable and enhance the pace of the development in this research area. Research gaps are presented by implementing a substantial analysis of the previously proposed methodologies. The analysis mainly identified the gaps in the development of data acquisition systems, model accuracy, and data types incorporated in the proposed models. Finally, research directions towards ITS are provided by exploring key topics necessary in the advancement of this research area.

Improving motorcycle motion perception by using innovative motorcycle headlight configurations: Evidence from simulator and test-track experiments

Many motorcycle accidents occur at intersections and are caused by other vehicle drivers who misperceive the speed and time-to-arrival of an approaching motorcycle. The two experiments reported here tested different motorcycle headlight configurations likely to counteract this perceptual failure. In the first experiment, conducted on a driving simulator, car drivers turned left in front of cars and motorcycles approaching an intersection under nighttime lighting conditions. The motorcycles were equipped with either a standard white central light, or one of three vertical configurations of white and yellow lights. The results showed that the standard configuration led to significantly more unsafe accepted gaps than the vertical configurations. In the second experiment, conducted on a test track using a similar task, the most promising motorcycle headlight configuration, i.e., the vertical yellow-white light arrangement (one central white light, plus one yellow light on the helmet and two yellow lights on the fork) was evaluated and compared to a standard configuration and a car. The vertical yellow-white headlight configuration again provided significant safety benefits as compared to the standard configuration. These findings demonstrate that motorcycle safety can be improved by headlight ergonomics that accentuate the vertical dimension of motorcycles. They also suggest that the driving simulator is a valid tool for conducting research on motorcycle headlight design.

Effects of taillight shape on conspicuity of vehicles at night

Taillight shape in a vehicle provides an essential lighting signal that enables the vehicle to be seen from the rear at night, thereby preventing rear-end crashes. This study aims to investigate the effects of taillight shape on vehicle conspicuity, and proposes ergonomic taillight shape solutions to vehicle designers and manufacturers. Two complementary experiments were conducted to examine three types of taillight shapes at three design levels. The first experiment was designed to investigate the detection speed of a driver and the fixation duration and fixation counts on leading vehicles with different taillight shapes, based on an eye-tracking methodology. The second experiment was designed to investigate the dynamic visual searching performance of a trailing driver for leading vehicles with different taillight shapes, based on a visual search task. The experimental results indicated that a long line-shaped taillight (striplight) was the optimal ergonomic solution for enhancing vehicle conspicuity. Vehicles with an enclosed contour-shaped taillight were more salient than those with an open contour-shaped taillight. Moreover, the experience and gender of the driver and the vehicle-observer distance were found to be closely related to vehicle conspicuity, and therefore, must be considered by vehicle designers when applying a specific taillight shape design. This study provides insights into the taillight shape design that not only aid vehicle designers or manufacturers in enhancing vehicle safety but also enable potential vehicle buyers to choose a safe lighting system.

Comparing drivers' visual attention at Junctions in Real and Simulated Environments

Driving simulation is widely used to answer important applied research questions, however, it is vital for specific driving tasks to undergo appropriate behavioural validation testing. Many previous validation studies have used simple driving tasks and measured relatively low-level vehicle control. The purpose of the current study was to investigate whether drivers' visual attention at intersections with different levels of demand, are similar in the simulator and on the road. Unlike simpler driving tasks, crossing intersections requires complex interactions with other vehicles governed by sequences of head and eye movements that may not be accurately captured in a simulated environment. In the current study we directly compare performance at simulated junctions with the same participants' behaviour in a real car. We compared drivers' visual attention in a high-fidelity driving simulator (instrumented car, 360-degree screen) and on-road in both low and medium demand driving situations. The low and medium demand driving situations involved the same motor movements, containing straight on, right turn and left turn manoeuvres. The low demand situations were controlled by the road environment and traffic lights, whereas medium demand situations required the driver to scan the environment and decide when it was safe to pull out into the junction. Natural junctions in Nottingham were used for the on-road phase and the same junctions were recreated in the simulator with traffic levels matched to those that were encountered on the real roads. The frequency and size of drivers' head movements were not significantly different between manoeuvres performed in the simulator and those conducted when driving on real roads. This suggests that drivers' broad search strategies in the simulator are representative of real-world driving. These strategies did change as a function of task demand - compared to low demand situations, behaviour at the medium demand junctions was characterised by longer junction crossing times, more head movements, shorter fixation durations and larger saccadic amplitudes. Although patterns of head movements were equivalent on road and in the simulator, there were differences in more fine-grained measures of eye-movements. Mean fixation durations were longer in the simulator compared to on-road, particularly in low-demand situations. We interpret this as evidence for lower levels of visual engagement with the simulated environment compared to the real world, at least when the task demands are low. These results have important implications for driving research. They suggest that high fidelity driving simulators can be useful tools for investigating drivers' visual attention at junctions, particularly when the driving task is of at least moderate demand.

Motorcycle door crashes: An evaluation of crash characteristics in Taipei City, Taiwan

Objectives

Crashes due to motorcyclists colliding with an open car door can cause devastating injuries. In Taiwan, such crashes typically occur when the motorcyclist is travelling alongside a row of parallel-parked cars, and a driver suddenly opens the door in front of or next to the motorcycle without determining whether it is safe to do so. Injuries resulting from motorcycle door crashes tend to be severe. This study examined the factors that contribute to motorcycle door crashes.

Methods

By using linked data from the National Traffic Crash Dataset and Emergency Medical Service for Taipei City for the years 2010–2015, this study estimated a mixed multinomial logit model to predict the likelihood of three types of door crashes: driver-door crashes, left passenger-door crashes, and right passenger-door crashes.

Results

Data on 8237 motorcycle door crashes were extracted from the two datasets and matched. The results from the mixed multinomial logit model revealed that illegal parking, older car occupants, teenage car occupants, intoxicated car occupants and motorcyclists, and motorcycle speeding contribute to driver-door crashes; and female passengers and taxis as the type of vehicle involved in crash are associated with left passenger-door crashes.

Conclusions

Our study suggested that controlling motorcycle speed, and prosecuting illegal parking and drink driving/riding may constitute effective countermeasures. The “Dutch Reach” intervention measure, which is commonly adopted in Europe for bicycle door crashes, should be applied in Taiwan to curb motorcycle door crashes, especially for elderly car occupants.

The effect of lighting conditions and use of headlights on drivers' perception and appraisal of approaching vehicles at junctions

Use of Daytime Running Lights (DRL) is mandatory in many countries for motorcycles, and in some for cars. However, in developing countries, DRLs may be optional or compliance low. The effect of car or motorcycle headlights and lighting conditions on Malaysian drivers' ability to perceive and judge the safety of pulling out was investigated. Stimuli were photographs depicting either daytime or nighttime taken at a T-junction with approaching vehicles with headlights on or off. Headlights improved drivers' ability to perceive cars and motorcycles in the nighttime photographs but not the daytime photographs, although this could be due to the bright weather in the photographs. Drivers judged it less safe to pull out when approaching motorcycles had headlights on than off, regardless of the lighting conditions, supporting the utility of DRL for motorcycles. Headlights did not affect judgements for cars, questioning the utility of DRL for cars. Practitioner Summary: The effect of headlights and lighting conditions on drivers' ability to perceive and make judgements about the safety of pulling out was investigated. Daytime Running Lights influenced drivers' decision-making about the safety of pulling out in front of motorcycles, illustrating the importance of having automatic headlights equipped.

Toward Performance Specifications for Flashing Warning Beacons

Yellow flashing warning beacons help protect front line service workers, including those in transportation, utility and construction sectors. To safeguard these workers, beacons should be readily detected and should provide veridical information about their relative movement. Two psychophysical laboratory experiments were conducted to provide empirical foundations for two aspects of warning beacon performance, detection and judgments of relative movement. In the first experiment reaction times were measured to the onset of flashing warning beacons varying in peak intensity while observers viewed different scene conditions. Observers also judged the visibility of nearby low-contrast targets in the presence of the flashing warning beacons. Asymptotic response times to the onset of beacons occurred when their peak intensity was at least 750 cd during daytime. Visibility of low contrast targets during nighttime, when glare is most critical, did not decrease substantially when the peak intensity was below 2000 cd. In the second experiment response times were measured to warning beacons of different flash-sequence patterns as they approached the observer. Judgments of gap closure were improved, relative to fully-on/fully-off flashing, with flash sequences where the minimum beacon intensity was at least 10% of the peak intensity and with two synchronized flashing beacons rather than one. With regard to performance specifications, the minimum value for the peak intensity of warning beacons should be 750 cd, with a maximum value of 2000 cd for detection. Fully-on/fully-off flash sequences should be changed to fully-on/partial-off to enhance judgments of gap closure on moving vehicles. Moreover, two flashing warning beacons, rather than one, should be mounted on service vehicles to improve gap closure judgments.

Improving motorcycle conspicuity through innovative headlight configurations

Most motorcycle crashes involve another vehicle that violated the motorcycle's right-of-way at an intersection. Two kinds of perceptual failures of other road users are often the cause of such accidents: motorcycle-detection failures and motion-perception errors. The aim of this study is to investigate the effect of different headlight configurations on motorcycle detectability when the motorcycle is in visual competition with cars. Three innovative headlight configurations were tested: (1) standard yellow (central yellow headlight), (2) vertical white (one white light on the motorcyclist's helmet and two white lights on the fork in addition to the central white headlight), and (3) vertical yellow (same configuration as (2) with yellow lights instead of white). These three headlight configurations were evaluated in comparison to the standard configuration (central white headlight) in three environments containing visual distractors formed by car lights: (1) daytime running lights (DRLs), (2) low beams, or (3) DRLs and low beams. Video clips of computer-generated traffic situations were displayed briefly (250ms) to 57 drivers. The results revealed a beneficial effect of standard yellow configuration and the vertical yellow configuration on motorcycle detectability. However, this effect was modulated by the car-DRL environment. Findings and practical recommendations are discussed with regard to possible applications for motorcycles.