Motorcycle Accident Risk Could Be Inflated by a Time to Arrival Illusion

Why do car drivers fail to give way to motorcycles at t-junctions?

Studies of accident statistics suggest that motorcyclists are particularly vulnerable to collisions with other vehicles which pull out of side roads onto a main carriageway, failing to give way to the approaching motorcycle. Why might this happen? The typical response of the car driver is that they looked in the appropriate direction but simply failed to see the motorcycle. To assess the visual skills of drivers in such scenarios we compared the behaviour of novice and experienced drivers to a group of dual drivers (with both car and motorcycle experience). Participants watched a series of video clips, displayed across three screens, depicting the approach to various t-junctions. On reaching the junction, participants had to decide when it was safe to pull out. Responses and eye movements were measured. The results confirmed that dual drivers had the safest responses at junctions, especially in the presence of conflicting motorcycles. On a range of visual measures both novice and experienced drivers appeared inferior to dual drivers, though for potentially different reasons. There were however no differences in the time it took all drivers to first fixate approaching motorcycles. Instead the differences appeared to be due to the amount of time spent looking at the approaching motorcycle. The experienced drivers had shorter gazes on motorcycles than cars, suggesting that they either process less salient motorcycles faster than cars, or that they terminated the gaze prematurely perhaps because they did not realise they were fixating a motorcycle. We argue that this is potential evidence for an oculomotor basis for Look But Fail To See errors.

A contribution to situation awareness analysis: understanding how mismatched expectations affect road safety

OBJECTIVE

The aim of the study was to clarify how knowledge elaborated by specific experience may lead to erroneous expectations during interactions between drivers and riders.

BACKGROUND

Situation awareness is partly determined by prior knowledge. Unshared knowledge may cause difficulties in managing driving interactions, but there is still an important gap in the literature devoted to this field of research.

METHOD

There were 226 participants, distinguished according to their vehicle use (for drivers, type of vehicle driven and whether they were exclusive or dual drivers; for motorcycle and scooter riders, the type of powered two-wheeler [PTW] used and its engine size) and their driving experience. Focusing on the most vulnerable users, we studied prior representations to interactions using a series of closed questions on drivers' performance relating to different stages of the interaction process from the perspective both of drivers' self-reflection and of riders' expectations.

RESULTS

Although most drivers are self-confident, their abilities tend to be questioned by riders. Owners of medium or large motorbikes feel that drivers do not assess their approach speed accurately. Similarly, scooter riders doubt drivers' ability to assess the distance that separates them from PTWs. Riders who use medium or large motorbikes are more likely to question drivers' skills in relation to crossing situations. Scooter riders do so more often for overtaking situations.

CONCLUSION

The development of shared prior knowledge is essential to prevent accidents and incidents between drivers and riders.

APPLICATION

To help improve effectiveness, we recommend specific ways of embedding each type of road user profile in training, prevention, and research.

Do common systems control eye movements and motion extrapolation?

People are able to judge the current position of occluded moving objects. This operation is known as motion extrapolation. It has previously been suggested that motion extrapolation is independent of the oculomotor system. Here we revisited this question by measuring eye position while participants completed two types of motion extrapolation task. In one task, a moving visual target travelled rightwards, disappeared, then reappeared further along its trajectory. Participants discriminated correct reappearance times from incorrect (too early or too late) with a two-alternative forced-choice button press. In the second task, the target travelled rightwards behind a visible, rectangular occluder, and participants pressed a button at the time when they judged it should reappear. In both tasks, performance was significantly different under fixation as compared to free eye movement conditions. When eye movements were permitted, eye movements during occlusion were related to participants' judgements. Finally, even when participants were required to fixate, small changes in eye position around fixation (<2°) were influenced by occluded target motion. These results all indicate that overlapping systems control eye movements and judgements on motion extrapolation tasks. This has implications for understanding the mechanism underlying motion extrapolation.

Motorcycle right-of-way accidents--a literature review

The most typical automobile-motorcycle collision take places when an automobile manoeuvres into the path of an approaching motorcycle by violating the motorcycle's right of way (ROW).

AIM

The present paper provides a comprehensive review of past research that examined motorcycle ROW accidents.

METHODS

Articles and publications were selected for relevance and research strength through a comprehensive search of major databases such as Transportation Research Information Services (TRIS), Compendex, and Medline.

RESULTS

Two major causes of such a crash scenario are the lack of motorcycle conspicuity and motorist's speed/distance judgment error, respectively. A substantial number of studies have manipulated physical characteristics of motorcycles and motorcyclists to enhance conspicuity, along with research addressing motorists' gap-acceptance behaviours and arrival time judgments when confronting motorcycles. Although various conspicuity aids have proven effective, some researchers reported that motorcyclist's/motorcycle's brightness per se may be less important as a determinant of conspicuity than brightness contrast between the motorcyclists and the surroundings. Larger vehicles tended to be judged to arrive sooner than motorcycles. Such a speed/distance judgment error is likely attributable to some psychological effects such that larger automobiles appear more threatening than motorcycles. Older motorists particularly have difficulties in accurately estimating the distance and the speed of an approaching motorcycle. Research examining the effects of conspicuity measures on motorists' speed/distance judgments when confronting motorcycles has been rather inconclusive.

CONCLUSIONS

Past research offers valuable insight into the underlying motorcycle ROW crash mechanisms. However, with ageing society and a rapid change in traffic composition (e.g., more larger motorcycles) in recent years, prior research findings should be updated. The present study finally provides recommendations for future research on motorcycle ROW accidents.

A mixed logit analysis of motorists' right-of-way violation in motorcycle accidents at priority T-junctions

Research suggested that motorists' right-of-way (ROW) violation in automobile-motorcycle gap-acceptance accidents at priority (i.e., stop-/yield-controlled) T-intersections has been a safety concern to motorcyclists. This study examines the characteristics of automobile-motorcycle gap-acceptance accidents that occurred at such locations. British Stats19 accident injury database during 1991-2005 are examined in detail. Automobile-motorcycle gap-acceptance accidents are classified into three crash scenarios: approach-turn, angle crossing, and angle merging crashes. Mixed (random parameters) logit models are estimated to investigate the contributory factors to motorists' ROW violation in these three crash types. Crash features are also compared among gap-acceptance accidents and other crash scenarios. The methodological approach adopted allows for the individuals within the observations to have different parameter estimates as opposed to a single parameter representing all observations (i.e., accounts for unobserved heterogeneity potentially relating to roadway/environmental characteristics, and motorist behaviours). It was found that motorcycles' ROW was more likely to be violated on non-built-up roads, and in diminished light conditions, with non-uniform effects across the observations. Elderly/female motorists appeared to be over-represented in gap-acceptance crashes. Implications of the findings are discussed.

Reducing contrast makes speeds in a video-based driving simulator harder to discriminate as well as making them appear slower

We investigated the effect of reducing image contrast on speed perception using a video-based driving simulator in which participants viewed pairs of scenes and were asked to judge whether the second scene was faster or slower than the first scene. We predicted two outcomes: (i) that vehicle speeds would become harder to discriminate, and (ii) that vehicle speeds would appear slower. There is previous evidence confirming the latter prediction in a less realistic computer-based driving simulation, but none demonstrating the former. Our results supported both predictions, each of which may have traffic-safety implications when reduced-contrast conditions are experienced in real life, such as with fog or when the driver has cataracts.

Auditory Feedback Influences Perceived Driving Speeds

Reducing the level of internal noise is seen as a goal when designing modern cars. One danger of such a philosophy is that one is systematically attempting to alter one of the cues that can be used by drivers to estimate speed and this could bias speed judgments and driving behaviour. Seven participants were presented with pairs of video-based driving scenes and asked to judge whether the second scene appeared faster or slower than the first (2-alternative forced-choice task using the method of constant stimuli). They either heard in-car noise at the level it occurred in the real world or reduced in volume by 5 dB. The reduction in noise led to participants judging speeds to be significantly slower and this effect was evident for all participants. This finding indicates that, when in-car noise is attenuated, drivers are likely to underestimate their speed, potentially encouraging them to drive faster and placing them at greater risk of crashing.