Driver brake vs. steer response to sudden forward collision scenario in manual and automated driving modes

In autonomous vehicle operation, situations may arise when the driver is required to re-engage in manual control of the vehicle. Whether the control handoff from vehicle to human is done in a structured or unstructured manner, the process may be affected by the driver’s state, i.e. distracted or not. The study reported here was designed to measure a non-distracted driver’s response to a sudden forward collision (FC) event, in which the driver would assume manual control of the autonomous vehicle. Three driving scenarios were investigated: autonomous vehicle driven with full collision avoidance support, autonomous vehicle driven without collision avoidance support, and vehicle driven in manual mode.Forty-eight volunteers participated in a simulator study conducted in VIRTTEX. It was found that, at handoff, (1) drivers in manual mode tended to use evasive steering, rather than braking, compared to drivers in both the autonomous modes, (2) between subjects variations in speed were higher for the automation with collision support condition than for the other two scenarios, (3) for both autonomous driving scenarios, drivers reaction times were longer than for manual driving. In some cases the driver response was so late and the distance remaining so reduced that crash avoidance might be unfeasible. At a minimum, results of this study suggest that drivers may benefit from appropriate driver assistance technologies when a crash imminent situation is suddenly encountered.     

Measuring driving workload of heavy vehicles at roundabouts

Correctly designed roundabouts proved to have positive safety and functional performances. However, they are also affected by peculiar disadvantages. In particular, they are difficult to manoeuvre, especially for heavy vehicle drivers. Despite these concerns, there are currently no driving workload metrics devoted to roundabouts.A novel methodological approach is proposed for trying to quantify workload impinging on heavy vehicle drivers when manoeuvring through complex at-grade intersections. Proper acquisition of input data constitutes the starting point for future research about ascertainment of workload for these particular road scenarios. The described procedure enables recording steering wheel angles performed by a driver when manoeuvring an articulated lorry through a complex at-grade intersection. A field trial was carried out for verifying the practical feasibility of proposed method in capturing driver’s steering behaviour. Dynamic data acquired via global navigation satellite system instrumentation were related to actual driver’s steering wheel behaviour captured by camera frames. As a complement to the experiment, selected steering behaviour metrics were calculated. Steering Entropy attributed a high difficulty level to the manoeuvres performed through the roundabout, whereas High Frequency Component and Steering Reversal Rate showed intensity and occurrences of driver’s corrections needed for controlling position of the semitrailer at the ring. It appears that even a single roundabout may represent an arduous task for drivers. The study concludes with recommendations for further research about workload imposed by roundabouts to heavy vehicle drivers, with special attention to successions of closely spaced roundabouts.     

Supervisor undermining and driving errors in truck drivers: A moderated mediation model

The present study focuses on the detrimental impact of supervisor undermining behaviors at work on driving errors for truck drivers, arguing for the mediating role of burnout. Moreover, this research highlights the moderating role of general self-efficacy in the relationships between supervisor undermining and burnout, and between burnout and driving errors, respectively. The data collected from a sample of 190 Romanian drivers supported a moderated mediation model in which burnout partially mediates the relation between supervisor undermining and driving errors, while self-efficacy moderates both aforementioned relationships. The conditional indirect effect of supervisor undermining on driving errors was significant when self-efficacy was low and non-significant when self-efficacy was high. Overall, our results emphasize the negative impact that supervisor undermining and burnout have on driving errors, while also highlighting the buffering effect of self-efficacy.     

Lifestyle traits as predictors of driving behaviour in urban areas of Greece

The aim of this study was to examine possible links between different lifestyle patterns and aberrant driver’s behaviour. Personal interviews were conducted in a representative sample of 324 adults (18–65), all residents of Crete. Aberrant driver’s behaviour was assessed by the ‘driver behaviour questionnaire’ (DBQ). Also to measure different dimensions of lifestyle, first, a 26-items questionnaire was used, and second, three questions measuring ‘driving without destination’, related in previous findings with road accident risk. Four lifestyle patterns: ‘religion/tradition’, ‘driving aimlessly’, ‘sports’ and ‘culture’ are significant predictors of ordinary violations. ‘Driving without destination’ has a significant effect all three DBQ factors (b positive). ‘Religion/tradition’ was related only to ordinary violations (b negative) and ‘sports’ has a positive impact on ordinary violations and a negative impact on ‘errors’. Two lifestyle factors are related to more dangerous driving: ‘Driving without destination’ and/or pursuing a more ‘athletic way of living’. Road safety campaigns must teach the first group to use other hobbies and activities to vent their feelings and the second, not to overestimate their abilities, while driving.     

Judgments of mean speed and predictions of route choice

How are driving speeds integrated when speeds vary along a route? In a first study, we examined heuristic processes used in judgments of mean speed when the mean speeds on parts of the trip varied. The judgments deviated systematically from objective mean speeds because the distances driven at different speeds were given more weight than travel time spent on the different distances. The second study showed that when there was a 10–15 min pause during a travel the effect on the mean speed decrease was underestimated for driving speeds of 90 km/h and higher. In the third study, the objective mean speeds and the subjective biased mean speed judgments were used to predict choices between routes with different speed limits. The results showed that subjective judgments predicted decisions to maximize mean speed significantly better than objective mean speeds. Finally, some applied and basic research implications of the results were discussed.     

Bias in older adults’ driving self-assessments: The role of personality

A convenience sample of 50 older drivers (M_age = 73.14, SD = 4.85) completed the Myers-Briggs Type Indicator® (MBTI®) Step III™ instrument and rated their own driving abilities (compared to all other drivers, same age drivers, and their own driving 20 years prior) and their ability to perform 68 specific driving-related behaviors. Each subject’s driving performance was also evaluated in a comprehensive on-road assessment conducted by a certified driving rehabilitation specialist, who rated the same 68 driving behaviors as well as driving performance. Drivers identified by the MBTI Step III instrument as Extraverted, Sensing, and (above median) Confident rated their driving significantly more favorably than Introverts, Intuitives, and below median Confidence drivers. Step III Sufficiency scales were associated with on-road performance: drivers with scores indicating low Confidence, low Stamina, or critical high levels of Compensatory Strain received significantly lower evaluations. Drivers with a Sensing preference or critical Strain score rated their driving significantly more favorably than evaluators did. These findings present preliminary evidence for the utility of personality assessments in identifying self-serving bias in driving self-evaluations, essential for safe self-regulation of driving.     

Strategic adaptation to performance objectives in a dual-task setting

How do people interleave attention when multitasking? One dominant account is that the completion of a subtask serves as a cue to switch tasks. But what happens if switching solely at subtask boundaries led to poor performance? We report a study in which participants manually dialed a UK‐style telephone number while driving a simulated vehicle. If the driver were to exclusively return his or her attention to driving after completing a subtask (i.e., using the single break in the xxxxx‐xxxxxx representational structure of the number), then we would expect to see a relatively poor driving performance. In contrast, our results show that drivers choose to return attention to steering control before the natural subtask boundary. A computational modeling analysis shows that drivers had to adopt this strategy to meet the required performance objective of maintaining an acceptable lateral position in the road while dialing. Taken together these results support the idea that people can strategically control the allocation of attention in multitask settings to meet specific performance criteria.     

放射科工作流程重组期间医务人员工作负荷的实验研究

通过对放射科实施工作流程重组期间医务人员工作负荷的研究分析,发现工作流程重组在提高工作效率的同时,也不可避免地增加医务人员工作负荷。只有运用针对性的措施,有效减轻工作负荷压力,才能保障工作流程重组顺利进行。     

Testing for effects of racial attitudes and visual contrast on the speed of a driver’s response to a pedestrian

Although ethnic minorities are overrepresented in pedestrian-vehicle collisions, previous driving studies did not examine racial attitudes in such collisions. Our objective was to determine whether the speed of a driver’s response to a pedestrian was affected by the driver’s racial attitudes and the contrast between the pedestrian’s skin colour and background. Participants viewed simulated driving scenes of a pedestrian on a road and pressed a button as soon as they saw an obstacle. Visual information, but not racial attitudes, affected the time it took observers to respond to pedestrian and non-pedestrian stimuli in driving scenes. Results indicated that contrast affected response time even when the stimulus was subliminal. We believe this is the first demonstration of contrast effects with subliminal stimuli in a driving context. Results have implications for traffic safety and for methodology used to study racial attitudes.