David Shinar

Aggressive driving: the contribution of the drivers and the situation

Abstract Aggressive driving is defined in terms of the frustration–aggression model. In that context aggressive driving is a syndrome of frustration-driven behaviors, enabled by the drivers environment. These behaviors can either take the form of instrumental aggression—that allows the frustrated driver to move ahead at the cost of infringing on other road users’ rights (e.g., by weaving and running red lights)—or hostile aggression which is directed at the object of frustration (e.g., cursing other drivers). While these behaviors may be reflective of individual differences in aggression, it is argued that the exclusive focus on the characteristics of the aggressive drivers and how to control them is short-sighted. Instead, this paper proposes a multi-factor approach to the problem. Five studies conducted so far tend to support this approach, by showing that specific aggressive behaviors—such as honking and running red lights—are associated with cultural norms, actual and perceived delays in travel, and congestion. Ergonomics-oriented approaches that involve environmental modifications are proposed.

VISUAL REQUIREMENTS FOR SAFETY AND MOBILITY OF OLDER DRIVERS

Efforts to assess visual deterioration with increasing age, coupled with new mechanisms proposed to limit the exposure of visually impaired drivers to driving risks, have emerged in response to the increase in older drivers. Visual functions discussed in this context include static acuity (photopic, mesopic, and in the presence of glare), dynamic visual acuity, visual field, contrast sensitivity, and motion perception. Exposure control mechanisms discussed include alternative periodic vision testing strategies, visual training, and environmental and vehicular modifications to accommodate the older driver. Finally, relevant research needs are addressed.

Screening for depression in stroke patients: the reliability and validity of the Center for Epidemiologic Studies Depression Scale.

This study examined the inter-observer reliability and validity of the Center for Epidemiologic Studies Depression Scale (CES-D) as a measure of depressive symptomatology in stroke patients, and its utility as a screening tool for depression in this population. The CES-D Scale is a brief questionnaire originally designed for use in community surveys. Twenty-seven non-aphasic patients enrolled in the Stroke Data Bank at the University of Maryland were interviewed by a research nurse using the CES-D. On the same day, each patient was independently evaluated by a research assistant using a psychiatric battery for depression and measures of cognitive, physical, and social functioning. Forty-one percent (11/27) of the patients were depressed according to clinical criteria for major or minor depression. With a cutpoint corresponding to the upper (most severe) 20% in community surveys, the CES-D Scale picked up 73% (8/11) of the depressed patients. In this sample no nondepressed patient scored over 16 on the CES-D (no false positives). The CES-D Scale scores correlated significantly with the other depression measures (r = .57 to r = .82, p less than .002) and did not correlate with the measures of cognitive, physical, or social functioning. Based on 24 patients who received a CES-D Scale score from both the nurse and the research assistant, inter-rater reliability was high (r = .76, p less than .001). Thus, the CES-D was found to be reliable and valid as a screening tool for assessing depression in stroke patients.

Self-reports of safe driving behaviors in relationship to sex, age, education and income in the US adult driving population.

This study analyzed the data of a health and safety survey conducted on a representative sample of the adult driving population. The analysis focused on the relationships between self-reported safe driving behaviors (including belt use, observing speed limits, and abstaining from drinking and driving), and demographic characteristics (including sex, age, education and income). The results showed that the three behaviors are quite independent of each other, and, contrary to some stereotypes, there is no single high-risk group that is most likely to violate all three safe driving behaviors. The only consistent effect was that of sex: women reported higher observance rates of all three behaviors. Reported use of safety belts increases with age and education for both men and women. However while for women the reported use increases with income, for males the reported use does not change with income. Complete avoidance of drinking and driving was reported by most drivers in all groups, and the high rates hardly varied across the different age, education, and income groups. The number of people who reported that they observe the speed limit all the time increased with age, but decreased with increasing education and income. The results have implications for identifying violation-specific high-risk groups, and stressing different factors for each.

Effects of an In-Vehicle Collision Avoidance Warning System on Short- and Long-Term Driving Performance

Many new in-vehicle systems focus on accident prevention by facilitating the driving task. One such driving aid is an in-vehicle collision avoidance warning system (IVCAWS), used to alert the driver to an impending collision. Our study evaluated the effects of an imperfect IVCAWS both on driver headway maintenance and on driver behavior in response to warning system errors. Our results showed that drivers tend to overestimate their headway and consequently drive with short and potentially dangerous headways, and that IVCAWSs are a useful tool for educating drivers to stimate headway more accurately. Moreover, our study showed that after a relatively short exposure to the system, drivers were able to maintain longer and safer headways for at least six months. The practical implications of these results are that the use of an IVCAWS should be considered for inclusion in driver education and training programs.

Eye Movements in Curve Negotiation

Eye movements and fixations of five drivers were recorded and superimposed on a videotaped recording of the dynamic visual scene as they drove on a two-lane rural road. The results showed that (1) on curved roads, the fixation pattern follows the road geometry, whereas on straight roads, the search behavior is less active, and most of the fixations are close to the focus of expansion. The results indicate that in driving through curves drivers direct foveal fixations to lateral placement cues rather than rely on peripheral vision; (2) the process of curve scanning begins in the approach zone prior to the curve itself, suggesting that perceptually the curve negotiating process precedes the curve by several seconds; (3) the search patterns on right and left curves are not symmetrical; visual excursions to the right on right curves are greater than eye movements to the left on left curves; and (4) fixation duration statistics may be related to accident rates on curves.

Multiple factors that determine performance with tables and graphs

Two experiments assessed the relative efficiency of line graphs, bar graphs, and tables, applying a multiple-factors approach to study the effects of the type of the required information, the complexity of the data, and the users familiarity with the display. information extraction tasks included reading exact values, comparing values, identifying trends, and reading maximum values. Tables led to faster responses for all tasks, and the accuracy for tables was equally high or higher than for graphs. Bar graphs and line graphs differed in their relative efficiency for the different tasks. The complexity of the data also affected the tasks differentially, as did prior familiarity with the display. Performance for most conditions improved with experience. Our findings demonstrate the benefits of a multiple-factors approach to the study of displays. Generalizations about the relative efficiency of displays and computational models of the task performance with displays must consider the various relevant factors if they are to serve as valid design aids.

Effects of uncertainty, transmission type, driver age and gender on brake reaction and movement time

PROBLEM Braking time (BT) is a critical component in safe driving, and various approaches have been applied to minimize it. This study analyzed the components of BT in order to assess the effects of age, gender, vehicle transmission type, and event uncertainty, on its two primary components, perception-reaction time and brake-movement time. METHOD Perception-reaction time and brake-movement time were measured at the onset of lights for 72 subjects in a simulator. The six experimental conditions were three levels of uncertainty conditions (none, some, and some + false alarms) and two types of transmission (manual and automatic). The 72 subjects, half male and half female, were further divided into three age groups (mean of 23, 30, and 62 years). Each subject had 10 trials in each of the three levels of uncertainty conditions. RESULTS Transmission type did not significantly affect either perception-reaction time or brake-movement time. Perception-reaction time increased significantly from 0.32 to 0.42 s (P < .05) as uncertainty increased but brake-movement time did not change. Perception-reaction time increased (from 0.35 to 0.43 s) with age but brake-movement time did not change with age. Gender did not affect perception-reaction time but did affect brake-movement time (males 0.19 s vs. females 0.16 s). IMPACT ON INDUSTRY At 90 km/h, a car travels 0.25 m in 0.01 s. Consequently, even such small effects multiplied by millions of vehicle-kilometers can contribute to significant savings in lives and damages.

Imperfect in-vehicle collision avoidance warning systems can aid drivers

An experiment was conducted to determine the effects of an in-vehicle collision avoidance warning system (IVCAWS) on driver performance. A driving simulator was driven by 135 licensed drivers. Of these, 120 received alerts from the IVCAWS when their headway to a lead car was less than 2s, and the other 15 (the control group) received no alerts. Drivers received varied alert interfaces: auditory, visual, and multimodal. The system had varied levels of reliability, determined by both false alarm rate and failure of the IVCAWS to alert to short headway. Results indicated that the IVCAWS led to safer (longer) headway maintenance. High false alarm rates induced drivers to slow down unnecessarily; large numbers of missed alerts did not have any significant impact on drivers. Driver acceptance of the system was mixed. Interface played a role in driver reliance on the system, with the multimodal interfaces generating least reliance. Actual or potential applications of this research include IVCAWS interface selection for greater system efficacy and user acceptance and the advisability of implementation, even of imperfect systems, for drivers who seek to maintain a safer headway.

Traffic sign symbol comprehension: a cross-cultural study

The objective of this study was to evaluate the comprehension levels of highway traffic sign symbols used in different countries, to identify underlying rules that affect comprehension levels, and recommend approaches to deal with the problem. The need for such an evaluation was based on todays travel culture where people are often licensed in one country and then drive—without any further training—in another country. We compared the comprehension levels of different traffic sign symbols in four countries with moderate to high levels of motorization: Canada, Finland, Israel, and Poland. Five different driver populations were sampled in each country: novice drivers, college students, tourists, problem drivers, and older drivers. There were large differences in comprehension among specific sign messages, different countries, and different driver populations. Signs were comprehended best when they were consistent with general ergonomic guidelines for display design as they relate to spatial compatibility, conceptual compatibility, physical representation, familiarity, and standardization. Illustrations of compliance with these principles and violations of these principles are presented, and their implication for traffic safety are discussed. Specific recommendations for sign design that is compliant with ergonomic principles, and for greater international cooperation in sign symbol design are made.