Flirting with Death: Variables Affecting Risk Taking at Intersections1

A series of four field studies were conducted to examine how motorists behaved at intersections. In each study, the proportion of drivers who pulled out in front of oncoming cars at varying temporal distances was recorded. In the first study, it was found that the proportion of turns in front of an approaching car was related to the log of the temporal distance between the subjects and the oncoming cars by a normal ogive. The remaining studies examined the effects that the presence of various types of audiences had on this risk-taking function. It was found that being forced to wait in a line of cars before being allowed to turn substantially increased the risks that drivers took, whereas the presence of other cars behind and/or beside the subject's car had no effect on the risk-taking function. A hypothesis explaining these effects in terms of the frustration of being forced to wait was supported while a social facilitation hypothesis was not. It was also discovered that males take more risks than females, a fact which could explain the higher accident rate for males.     

Cars overtaking cyclists on different urban road types – Expectations about passing safety are not aligned with observed passing distances

Cars overtaking cyclists have been identified as a source of crashes and subjective risk. Several studies investigated the passing distance for different road types. There has been less research concerning cyclists’ expectations concerning the passing distance at different road types. Thus, we aim at contrasting cyclists’ expectations about the passing safety for different speed limits and cycling infrastructures with the passing distances observed at corresponding urban road types. For this purpose, we show participants images of a predefined set of survey zones in a web-based survey, and ask them about the expected passing safety of cars overtaking them when imagining riding their bikes at these locations. We measure the observed passing distances at the same survey zones with a bike-mounted sensor. We find that cars meet the German legal minimum passing distance of 1.5 m in towns in only 30% of all observed events. In 30 km/h speed zones, passing distances at roads featuring dedicated cycling infrastructure (e.g. bike lanes, cycling boulevards) are decreased as compared to those featuring no cycling infrastructure. In contrast, people estimate that the passing safety on roads with dedicated cycling infrastructure is safer than without cycling infrastructure. This effect is even more pronounced on living streets. Situations where oncoming cars (e.g. living streets, ‘opposite’ roads) must be passed in close distance are apparently not perceived as particularly dangerous. Cycling tracks in 50 km/h speed zones increase both the observed passing distance and the corresponding expectations about passing safety. Taken together, the qualitative comparison of the two datasets implies that cyclists’ expectations about cars passing them in a more adequate and safe distance in streets with reduced speed limits and dedicated cycling infrastructure are not justified in light of the actually observed passing distances. Possible explanations for the contradicting patterns could be that cyclists prefer situations where space is explicitly dedicated for bikes, that they account for the anticipated car traffic volume, and that they assume oncoming cars as less dangerous to pass.     

Antigravity hills are visual illusions

Antigravity hills, also known as spook hills or magnetic hills, are natural places where cars put into neutral are seen to move uphill on a slightly sloping road, apparently defying the law of gravity. We show that these effects, popularly attributed to gravitational anomalies, are in fact visual illusions. We re-created all the known types of antigravity spots in our laboratory using tabletop models; the number of visible stretches of road, their slant, and the height of the visible horizon were systematically varied in four experiments. We conclude that antigravity-hill effects follow from a misperception of the eye level relative to gravity, caused by the presence of either contextual inclines or a false horizon line.     

What a car does to your perception: Distance evaluations differ from within and outside of a car

Almost a century ago it was first suggested that cars can be interpreted as tools, but consequences of this assumption were never tested. Research on hand-held tools that are used to manipulate objects in the environment suggests that perception of near space is extended by using tools. Literature on environment perception finds perception of far space to be modulated by the observer’s potential to act in the environment. Here we argue that a car increases the action potential and modulates perception of far space in a way similar to how hand-held tools modulate perception of near space. Five distances (4 to 20 meters) were estimated by pedestrians and drivers before and after driving/walking. Drivers underestimated all distances to a larger percentage than did pedestrians. Underestimation was even stronger after driving. We conclude that cars modulate the perception of far distances because they modulate the driver’s perception, like a tool typically does, and change the perceived action potential.     

Cross-cultural effects on the perception and appraisal of approaching motorcycles at junctions

Both perceptual errors (failing to perceive) and appraisal errors (failing to make a correct judgment about safety) could explain the relatively high number of pulling out at the junctions involving approaching motorcycles in relation to cars. Two experiments were conducted to investigate the effect of exposure to motorcycles on these types of errors by comparing drivers from Malaysia where motorcycles are very common with drivers from the UK where motorcycles are rare. Experiment 1 investigated drivers’ ability to perceive approaching vehicles (car or motorcycle) located at different distances (near, intermediate and far) on UK and Malaysian roads. There was no difference between Malaysian and UK drivers in overall ability to perceive the approaching vehicles but Malaysian drivers were relatively good at perceiving motorcycles at further distances. Experiment 2 investigated drivers’ judgments about whether or not it was safe to pull out on the same roads and found that Malaysian drivers were more likely to judge it was safe to pull out as compared to UK drivers. Findings suggest that high exposure to motorcycles may reduce vehicle effects on perception for Malaysian drivers. However they may make more risky appraisals about safety of pulling out, which might contribute to the high accident and fatality rates in Malaysia.     

Knowledge and strategies used by adolescents to compare duration of movement by two objects

This study investigated the knowledge and strategies used by senior high school students to compare durations of movement by two objects. The developmental process during adolescence was also examined by comparing the results with those published for Grade 7 to Grade 9 students and university undergraduates. A cathode-ray tube monitor was used to present images of two cars traveling in the same direction for various durations and distances. 30 Grade 12 students were asked to identify which of the cars had traveled for a longer duration and why. Analysis suggested that the strategies develop during adolescence in a sequence. Initially, comparison of durations was based on the relative distance traveled by the two cars. Then the comparison was based exclusively on knowledge that "duration = temporal starting point- temporal stopping point." Finally, the two types of knowledge were used appropriately according to the characteristics of the specific task.     

Visibility distances with halogen and conventional headlights

Abstract.— Using visibility distance as a criterion, halogen and conventional continental European high and low-beam headlights were compared in a series of field experiments. On high-beam without opposing light the halogen headlights offered about 25% longer visibility distances than the conventional headlights. With both opposing cars using low-beam there was a slight advantage (<5 m) in favour of halogen headlights. The optimal dipping distance was a function of high-beam system (intensity) rather than low-beam system. Small differences in aiming, atmosphere etc. caused larger differences in visibility distance than did the headlight system.     

Accuracy of Pace Count as a Distance Estimation Procedure

The purpose of this study was to assess the accuracy of pace counting under varying conditions and to resolve discrepancies between U.S. Army Field Manual 21-26 (FM 21-26; Department of the Army, 1987) and pace-counting research conducted by Powers (1964). Two experiments were designed to measure accuracy of distance estimations from pace counting on-road and off-road under conditions of daylight and darkness. In both experiments, male soldiers enrolled in One Station Unit Training (OSUT) were trained to estimate distances based on pace counts performed on a flat road during daylight. In Experiment 1, the soldiers were tested on a flat road during both daylight and darkness; in Experiment 2, soldiers were tested off-road on hilly terrain during both daylight and darkness. The general finding in both experiments was that soldiers tended to underestimate distance during day- light and to overestimate distance during darkness. These errors became greater as the test conditions became less like the training condition. It was concluded that pace count should be adjusted, as indicated by FM 21-26, either by opportunities for more training time or by standard pace-count adjustment formulas. Also, because of inherent inaccuracies, pace count should be used as a backup and/or in conjunction with other land navigation techniques.     

Glance analysis of driver eye movements to evaluate distraction

With the increasing use of in-vehicle devices in cars, an understanding of the safety implications of secondary tasks has become crucial. It is now possible to study the effects of many in-vehicle devices and tasks on driving by using head-mounted eye-tracking devices (HEDs) to collect eye positions and pupil diameters, which have been considered indicators of attentional focus. The collection of eye-position and pupil-diameter data of automobile drivers under on-road conditions and while completing various secondary tasks is described in this paper. Drivers were asked to drive on a preselected two-lane road for a total distance of 22 miles while gaze data were recorded using a HED. Longer off-road fixation durations were observed in radio-tuning and rearview mirror checking tasks, but not in the odometer checking task. In addition, the standard deviations of fixation displacements during a cognitive task involving the computation of a date for a meeting were shorter than those observed during normal driving.     

AN EXPLORATORY STUDY OF PREDICTIVE JUDGMENTS IN A TRAFFIC SITUATION

Observers seated in a car were required to predict where they would meet an oncoming car (Exp. I). Meeting point predictions were found to be systematically biased in the direction of the midpoint between cars. The error was proportional to the distance between midpoint and meeting point. A reduction in the errors occurred when the observers were allowed to check their predictions (Exp. II). Perfect agreement was found to hold between subjective midpoint judgments (Exp. III) and meeting point predictions, the former showing a small but obvious regression toward the meeting point.     

Perceptual training to increase drivers’ ability to spot motorcycles at T-junctions

Motorcyclists too often collide with other road users who pull out of side roads in front of them. These other road users typically report making all the necessary visual checks, despite failing to see the approaching motorcycle. These Look But Fail To See errors appear to be attenuated in road users who themselves have motorcycling experience, suggesting that motorcycle exposure may lower thresholds for spotting these vulnerable road users through natural perceptual learning. This raises the possibility that perceptual training could improve car drivers’ abilities to spot motorcycles. Two experiments are reported. The first experiment demonstrated that a T-junction task, requiring participants to detect an approaching vehicle in briefly displayed images, was sensitive to participants’ motorcycle experience, with dual drivers (who both ride motorcycles and drive cars) performing better than average car drivers. Following this, a second experiment split the car drivers into 2 groups. One group undertook a Pelmanism task requiring participants to match pairs of motorcycles, while the control group had to match pairs of fruit. When the two groups were re-tested on the T-junction task, the group who had undergone perceptual training for motorcycles via the Pelmanism task, were better able to identify approaching motorcycles, but not approaching cars. The results suggest that gamification of perceptual training for motorcycle detection provides a novel opportunity to improve driver safety.     

SUBJECTIVE TEMPORAL DISTANCE AND EMOTIONAL INVOLVEMENT

BRATFISCH, O., EKMAN, G., LUNDBERG, U., and KRÜGER, K. Subjective temporal distance and emotional involvement. Scand. J. Psychol. , 1971, 12, 147–160. –Three experiments were conducted in which subjects were required to estimate the subjective temporal distances of various historical periods, each of which was named after some person, event, or social process. In all, 65 subjects participated. In related experiments the same subjects estimated their degree of emotional involvement in what might have happened to people living during the various periods named. Using the actual dates when the events took place, the relation between objective and subjective temporal distance was found to be described by a simple power function. Emotional involvement was shown to be inversely related in a simple monotonic manner to both subjective and objective temporal distance, when other variables were so far as possible held constant. A number of different alternative power functions as well as an exponential and a logarithmic function were fitted to the empirical data. A specific type of power function with three empirical constants and a simple exponential function were found to describe experimetal data to a good approximation.     

Visual strategies used for time-to-arrival judgments in driving

To investigate the sources of visual information that are involved in the anticipation of collisions we recorded eye movements while participants made relative timing judgments about approaching vehicles at a junction. The avoidance of collisions is a critical aspect in driving, particularly where cars enter a line of traffic from a side road, and the present study required judgments about animations in a virtual driving environment. In two experiments we investigated the effects of (i) the angle of approach of the vehicle and the type of path (straight or curved) of the observer, and (ii) the speed of both the observer and the approaching car. Relative timing judgments depend on the angle of approach of the other vehicle (judgments are more accurate for perpendicular than for obtuse angles). Eye-movement analysis shows that visual strategies in relative timing judgments are characterised by saccadic eye movements back and forth between the approaching car and the road ahead, particularly the side line which may serve as a spatial reference point. Results suggest that observers use the distance of the car from this reference point for their timing judgments.     

Forgetting near‐accidents: the roles of severity,culpability and experience in the poor recall of dangerous driving situations

It is often assumed that real‐life events such as minor road accidents and near accidents will be well remembered. However, surveys of self‐reported accidents suggest that respondents apparently forget approximately one third of their road accidents each year. This paper explores this possibility by looking at memory for the near‐accidents in which drivers are involved. In a pilot study drivers carried microcassette recorders in their cars and reported near‐accidents after each journey. These data confirmed that the frequency of near‐accidents is greatly underestimated when subjects are simply asked to recall them. The main study then compared reports and recalls of over 7000 car journeys from 80 subjects over the course of a year. These included more than 400 reports or recalls of near‐accidents. The influences of the driver's experience, the severity of the near‐accident, and the driver's self‐perceived degree of blame were additionally explored. It is concluded that near‐accidents are generally forgotten extremely rapidly, with an estimated 80% of incidents being no longer reported after a delay of up to two weeks. Serious near‐accidents and those where the driver admitted being to blame in the incident were least likely to be forgotten. Copyright © 2000 John Wiley & Sons, Ltd.     

Effects of variable message signs for slippery road conditions on driving speed and headways

This field study investigated the effects of two variable message signs (VMS) on driver behaviour. Specifically, the signs were a warning sign for slippery road conditions and a minimum headway sign. The study was performed as a before-and-after experiment at three test sites in Finland with an after period covering two winter seasons. The results showed that the slippery road condition sign reduced the mean speed on slippery roads by 1–2 km/h in addition to the decrease caused by the adverse road conditions. The minimum headway sign decreased the proportion of headways shorter than 1.5 s for cars in car-following situations, in addition to a speed reduction of 1 km/h. The effects were somewhat smaller during the second winter than the first.     

Categorization does not promote symmetry in Guinea baboons (<Emphasis Type="Italic">Papio papio</Emphasis>)

Humans have the capacity to use stimuli interchangeably by forming equivalence classes, and this ability seems to be supported by our language system. According to Sidman and Tailby (Conditional discrimination vs. matching to sample: an expansion of the testing paradigm. J Exp Anal Behav 37:5–22, 1982), the formation of equivalence classes require that three relations are derived among the class members, and past experiments have shown that one of these relations, i.e., symmetry, corresponding to the ability to reverse a relation (if A → B, then B → A), is extremely difficult to obtain in non-human animals. Because language development and the ability to form equivalence classes both co-occur in children with an increased ability to form categories, the current study tested the idea that category learning might promote symmetry in a nonhuman primate species. In Experiment 1, twelve Guinea baboons (Papio papio) were trained to associate 60 pictures of bears and 60 pictures of cars to two category labels, before being tested in symmetry trials. In Experiment 2, symmetry was trained and tested by reversing the association order between labels and pictures, using a new set of stimuli. In both experiments, the baboons successfully demonstrated category discrimination, but had only a weak (though significant) tendency to respond in accordance with symmetry during test trials. Altogether, our results confirm that symmetry is inherently difficult in non-human animals. We discuss possible explanations for such a limitation and give reasons for thinking that the effects of categorization on symmetry should be further investigated.     

The effects of dimmable road lighting: A comparison of measured and perceived visibility

By dimming road lighting, energy can be conserved without compromising traffic safety. This paper presents a study carried out on the effect of different lighting levels from road luminaires on drivers’ visual performance on a low traffic urban road. The small uniform target was used to evaluate the visibility performance of the drivers. The results obtained from subjective graded visibility were compared with contrast and the Adrian model. Results indicated a strong correlation between subjective graded visibility and contrast (R² = 0.94) and a positive correlation between subjective graded visibility and the Adrian model (R² = 0.88). Target’s location in relation to road luminaires had a considerable effect on its visibility. However, visibility is not a monotonic function of road lighting level. In the absence of glare from an oncoming car, 49% (3557 lm) of road lighting intensity provided better contrast and mean visibility than 100% (7252 lm) and 71% (5179 lm) of road lighting intensities. The glare from oncoming cars reduced visibility. However, no statistically significant effect of road lighting level on visibility under glare could be found.     

Making Road Traffic Safer: Reply to Ori

Abstract

In order to reduce the death toll of road traffic it is necessary to focus on how vehicles and roads can be improved. Like other dangerous machines, motor vehicles should be equipped with safety devices that prevent mistakes by the operator from leading to serious consequences. Speed limiters that prevent driving at illegal speeds would save many lives, and so would alcohol interlocks. Meshi Ori's proposal that most cars should be replaced by motorcycles would not lead to the moral improvement that he hopes for. We need motor vehicles with better, not worse, protection of the driver and passengers than the cars presently in use.     

The New Trolley Problem: Driverless Cars and Deontological Distinctions

Discussion of the ethics of driverless cars has often focused on supposed real-life versions of the famous trolley problem. In these cases, a driverless car is in a position where crashing is unavoidable and all possible crashes risk harm: for example, it can either continue on its current path and crash into five pedestrians or swerve and crash into one pedestrian. There are significant disanalogies between the human versions of the trolley problem and situations faced by driverless cars which affect the application and moral significance of key deontological distinctions, such as the distinction between doing and allowing harm. The application and moral significance of the doing/allowing distinction in the context of the behaviour of driverless cars depend on (a) our conception of the behaviour of driverless cars; (b) the forms of driverless cars that are developed and used; (c) the background expectations of programmers/manufacturers/owners of driverless cars and the conditions of being able to put those cars on the roads. These are as yet unsettled – and may even be undetermined. Nonetheless, trolley problems may still be useful in thinking about the ethics of driverless cars.     

Objects of Interpretation

The paper examines the relation between interpretation and the objects of interpretation, principally, but not exclusively, in the realm of art. Several theses are defended: that interpretation cannot proceed without prior determination of the kind of thing being interpreted; that the mode of interpretation is determined by the nature of its object; that interpretation, of a meaning-determining rather than generic kind, focuses at the level of works , not descending to a bedrock of "mere objects"; that because works and their appropriate mode of interpretation are constituted by convention-bound practices, it follows that no clear line can be drawn between properties "in" a work and those "imputed to" it through interpretive procedures endorsed by the practice. The debate over constructivism or "imputationalism"– between Margolis and Krausz, on the one hand, and Stecker and Levinson, on the other – is engaged with an attempt to show a core of truth in each of the conflicting theories, once the right distinction between object, work, and interpretation is in place.