Judgments of approach speed for motorcycles across different lighting levels and the effect of an improved tri-headlight configuration

A method to enhance drivers' hazard perception at night based on "knowledge-attitude-practice" theory

During nighttime driving, the inherent challenges of low-illuminance conditions often lead to an increased crash rate and higher fatalities by impairing drivers' ability to recognize imminent hazards. While the severity of this issue is widely recognized, a significant research void exists with regard to strategies to enhance hazard perception under such circumstances. To address this lacuna, our study examined the potential of an intervention grounded in the knowledge-attitude-practice (KAP) framework to bolster nighttime hazard detection among drivers. We engaged a cohort of sixty drivers split randomly into an intervention group (undergoing specialized training) and a control group and employed a holistic assessment that combined eye movement analytics, physiological response monitoring, and driving performance evaluations during simulated scenarios pre- and post-intervention. The data showed that the KAP-centric intervention honed drivers' visual search techniques during nighttime driving, allowing them to confront potential threats with reduced physiological tension and ensuring more adept vehicle handling. These compelling findings support the integration of this methodology in driver training curricula and present an innovative strategy to enhance road safety during nighttime journeys.

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.

Security Assessment of Urban Areas through a GIS-Based Analysis of Lighting Data Generated by IoT Sensors

The current perspective about urban development expects 70% of energy consumption will be concentrated in the cities in 2050. In addition, a growing density of people in the urban context leads to the need for increased security and safety for citizens, which imply a better lighting infrastructure. Smart solutions are required to optimize the corresponding energy effort. In developing countries, the cities’ lighting is limited and the lighting world map is strongly significant about the urban density of the different areas. Nevertheless, in territories where the illumination level is particularly high, such as urban contexts, the conditions are not homogenous at the microscale level and the perceived security is affected by artificial urban lighting. As an example, 27.2% of the families living in the city of Milan, ombardy Region, Italy, consider critical the conditions of lighting in the city during the night, although the region has diffused infrastructure. The paper aims to provide a local illuminance geographic information system (GIS) mapping at the neighborhood level that can be extended to the urban context. Such an approach could unveil the need to increase lighting to enhance the perceived safety and security for the citizens and promote a higher quality of life in the smart city. Lighting mapping can be matched with car accident mapping of cities and could be extended to perceived security among pedestrians in urban roads and green areas, also related to degradation signs of the built environment. In addition, such an approach could open new scenarios to the adaptive street lighting control used to reduce the energy consumption in a smart city: the perceived security of an area could be used as an additional index to be considered during the modulation of the level of the luminosity of street lighting. An example of a measurement set-up is described and tested at the district level to define how to implement an extensive monitoring campaign based on an extended research schema.

Conspicuity Equipment and Its Contribution to the Welfare of Horse and Rider Combinations Using the Road System in the United Kingdom

Limited research exists regarding proximity of vehicles to "vulnerable road users" and effects of "conspicuity equipment". Previous studies stated over 60% of horse/rider combinations experience near-miss traffic collisions in any one year, whereas use of fluorescent/reflective (FR) equipment did not decrease occurrences. Similarly, research into vehicle proximity to bicycles reported no significance in cyclists wearing FR. This study undertook a similar field experiment using a horse/rider combination wearing different conspicuity equipment to test proximity distance. Two horses with similar height, age, base coat color, and temperament were ridden using four conspicuity measures 60 times each (n = 240) along a straight 0.8 km lane. Measures were chosen by random crossover with two selected for each separate trip. These were an FR "tabard", a novel black/white pattern (BW), flashing lights on a helmet (L), and control of mid-blue (C). A novel proximity meter was used on the saddle pommel and distance/approach either front or rear were logged into a voice recorder. Analysis reported a significant difference between all measures and proximities observed (P = .000). Mann-Whitney tests concluded significant differences in proximity in C versus L and BW (P = .000; P = .000), respectively. FR versus C showed no significant difference in proximity (P = .005). L versus BW reported no significant difference in proximity (W = 3640.0, P = .958). Results may suggest wearing conspicuity equipment of L or BW outperforms both C and FR. Further study is recommended to test these findings, and it is pertinent to still consider suggesting the use of FR equipment due to previous positive findings with other road users.

Motorcycle crashes potentially preventable by three crash avoidance technologies on passenger vehicles

OBJECTIVE

The objective of this study was to identify and quantify the motorcycle crash population that would be potential beneficiaries of 3 crash avoidance technologies recently available on passenger vehicles.

METHODS

Two-vehicle crashes between a motorcycle and a passenger vehicle that occurred in the United States during 2011-2015 were classified by type, with consideration of the functionality of 3 classes of passenger vehicle crash avoidance technologies: frontal crash prevention, lane maintenance, and blind spot detection. Results were expressed as the percentage of crashes potentially preventable by each type of technology, based on all known types of 2-vehicle crashes and based on all crashes involving motorcycles.

RESULTS

Frontal crash prevention had the largest potential to prevent 2-vehicle motorcycle crashes with passenger vehicles. The 3 technologies in sum had the potential to prevent 10% of fatal 2-vehicle crashes and 23% of police-reported crashes. However, because 2-vehicle crashes with a passenger vehicle represent fewer than half of all motorcycle crashes, these technologies represent a potential to avoid 4% of all fatal motorcycle crashes and 10% of all police-reported motorcycle crashes.

DISCUSSION

Refining the ability of passenger vehicle crash avoidance systems to detect motorcycles represents an opportunity to improve motorcycle safety. Expanding the capabilities of these technologies represents an even greater opportunity. However, even fully realizing these opportunities can affect only a minority of motorcycle crashes and does not change the need for other motorcycle safety countermeasures such as helmets, universal helmet laws, and antilock braking systems.

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.

Robust Underestimation of Speed During Driving: A Field Study

Traffic reports consistently identify speeding as a substantial source of accidents. Adequate driving speeds require reliable speed estimation; however, there is still a lack of understanding how speed perception is biased during driving. Therefore, we ran three experiments measuring speed estimation under controlled driving and lighting conditions. In the first experiment, participants had to produce target speeds as drivers or had to judge driven speed as passengers. Measurements were performed at daylight and at night. In the second experiment, participants were required to produce target speeds at dusk, under rapidly changing lighting conditions. In the third experiment, we let two cars approach and pass each other. Drivers were instructed to produce target speeds as well as to judge the speed of the oncoming vehicle. Here measurements were performed at daylight and at night, with full or dipped headlights. We found that passengers underestimated driven speed by about 20% and drivers went over the instructed speed by roughly the same amount. Interestingly, the underestimation of speed extended to oncoming cars. All of these effects were independent of lighting conditions. The consistent underestimation of speed could lead to potentially fatal situations where drivers go faster than intended and judge oncoming traffic to approach slower than it actually is.

Effects of oncoming vehicle size on overtaking judgments

During overtaking maneuvers on two-way highways drivers must temporarily cross into the opposite lane of traffic, and may face oncoming vehicles. To judge when it is safe to overtake, drivers must estimate the time-to-contact (TTC) of the oncoming vehicle. Information about an oncoming vehicle's TTC is available in the optical expansion pattern, but it is below threshold during high-speed overtaking maneuvers, which require a large passing distance. Consequently, we hypothesized that drivers would rely on perceived distance and velocity, and that their overtaking judgments would be influenced by oncoming vehicle size. A driving simulator was used to examine whether overtaking judgments are influenced by the size of an oncoming vehicle, and by whether a driver actively conducts the overtaking maneuver or passively judges whether it is safe to overtake. Oncoming motorcycles resulted in more accepted gaps and false alarms than larger cars or trucks. Results were due to vehicle size independently of vehicle type, and reflected shifts in response bias rather than sensitivity. Drivers may misjudge the distances of motorcycles due to their relatively small sizes, contributing to accidents due to right-of-way violations. Results have implications for traffic safety and the potential role of driver-assistance technologies.

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

The most frequent cause of motorcycle accidents occurs when another vehicle violates the motorcycle's right-of-way at an intersection. In addition to detection errors, misperception of the approaching motorcycle's speed and time-to-arrival is another driver error that accounts for these accidents, although this error has been studied less often. Such misperceptions have been shown to be related to the small size of motorcycles and to their small angular velocity when approaching. In two experiments we tested the impact of different motorcycle headlight configurations in various ambient lighting conditions (daytime, dusk, and nighttime). The participants drove on a driving simulator and had to turn left across a line of vehicles composed of motorcycles and cars. The motorcycles were approaching at different speeds and were equipped with either a "standard" headlight, a "horizontal" configuration (added to the standard headlight were two lights on the rearview mirrors so as to visually increase the horizontal dimension of the motorcycle), a "vertical" configuration (one light on the rider's helmet and two lights on the fork were added to the standard headlight so as to increase the vertical dimension of the motorcycle), or a "combined" configuration (combining the horizontal and vertical configurations). The findings of the first experiment in nighttime conditions indicated that both the vertical and combined configurations significantly increased the gap car drivers accepted with respect to the motorcycle as compared to the standard configuration, and that the accepted gaps did not differ significantly from those accepted for cars. The advantage of the vertical and combined configurations showed up especially when the motorcycle's approach speed was high. The findings of the second experiment in dusk and daytime conditions indicated similar patterns, but the headlight-configuration effect was less pronounced at dusk, and nonsignificant during the day. The results are discussed with regards to possible applications for motorcycles.

Driving with homonymous visual field loss: Does visual search performance predict hazard detection?

Introduction

Stroke often causes homonymous visual field loss, which can lead to exclusion from driving. Retention of a driving licence is sometimes possible by completing an on-road assessment, but this is not practical for all. It is important to find simple tests that can inform the assessment and rehabilitation of driving-related visual-motor function.

Method

We developed novel computerised assessments: visual search; simple reaction and decision reaction to appearing pedestrians; and pedestrian detection during simulated driving. We tested 12 patients with stroke (seven left, five right field loss) and 12 controls.

Results

The homonymous visual field defect group was split into adequately compensated or inadequately compensated groups based on visual search performance. The inadequately compensated group had problems with stimuli in their affected field: they tended to react more slowly than controls and in the driving task they failed to detect a number of pedestrians. In contrast, the adequately compensated group were better at detecting pedestrians, though reaction times were slightly slower than controls.

Conclusion

We suggest that our search task can predict, to a limited extent, whether a person with stroke compensates for visual field loss, and may potentially identify suitability for specific rehabilitation to promote return to driving.

Influence of front light configuration on the visual conspicuity of motorcycles

A recent study (Cavallo and Pinto, 2012) showed that daytime running lights (DRLs) on cars create "visual noise" that interferes with the lighting of motorcycles and affects their visual conspicuity. In the present experiment, we tested three conspicuity enhancements designed to improve motorcycle detectability in a car-DRL environment: a triangle configuration (a central headlight plus two lights located on the rearview mirrors), a helmet configuration (a light located on the motorcyclist's helmet in addition to the central headlight), and a single central yellow headlight. These three front-light configurations were evaluated in comparison to the standard configuration (a single central white headlight). Photographs representing complex urban traffic scenes were presented briefly (for 250ms). The results revealed better motorcycle-detection performance for both the yellow headlight and the helmet configuration than for the standard configuration. The findings suggest some avenues for defining a new visual signature for motorcycles in car-DRL environments.