Anuj K. Pradhan

Keep your eyes on the road: young driver crash risk increases according to duration of distraction

PURPOSE Secondary task engagement that distracts the driver is a contributing factor to motor vehicle crashes among adults. However, the association between eye glance duration and crash risk with novice teenage drivers has not been determined. METHODS Vehicles of 42 newly licensed teenage drivers were instrumented with cameras, accelerometers, Global Positioning System(s) (GPS), and other devices. Data were collected continuously for 18 months. Crashes and near crashes (CNCs) were identified by examining highly elevated gravitational force events. Video footage of the 6 seconds prior to each CNC and randomly sampled non-CNC road segments were coded for the duration of eye glances off the forward roadway and the presence of secondary task engagement. The likelihood (odds ratios) of CNC due to eye glance behavior was calculated by comparing the prevalence of secondary task engagement and duration of eyes off road prior to CNC with the prevalence and duration of eyes off road during non-CNC road segments. RESULTS Crash risk increased with the duration of single longest glance during all secondary tasks (OR=3.8 for >2 s) and wireless secondary task engagement (OR=5.5 for >2 s). Single longest glance provided a more consistent estimate of crash risk than total time eyes off the forward roadway. CONCLUSIONS Those eye glances away from the forward roadway involving secondary tasks increased the likelihood of CNC. The longer the duration of eye glance away from the road the greater the risk, regardless of type of secondary task. Education and policy discouraging secondary task engagement, particularly for prolonged periods, is warranted.

Empirical Evaluation of Hazard Anticipation Behaviors in the Field and on Driving Simulator Using Eye Tracker

Eye behaviors have been used with driving simulators to evaluate the effectiveness of novice and older driver training programs. Driving simulators are often favored when drivers must be placed in risky situations. Because there was no study of whether eye behaviors observed on a driving simulator in risky scenarios were also observed in the field, the authors had both trained and untrained novice drivers maneuver a controlled set of 10 scenarios on a driving simulator. The scenarios were similar to a set of scenarios that a different, matched set of trained and untrained drivers had navigated in the field. Drivers in this simulator study were trained with the same PC program used by drivers in the field study. Five of the scenarios that the trained drivers saw on the simulator and in the field were similar to those seen in training on a PC (near transfer); the other five were similar in concept to those in training but different in surface features (far transfer). A fixation on the region of a scenario that had information relevant to identifying a risk was scored as recognizing the risk. On the simulator, trained drivers recognized the risk 41.7% more often than untrained drivers in the near-transfer scenarios and 32.6% more often in the far-transfer scenarios. In the field, trained drivers recognized the risk 38.8% more often in the near-transfer and 20.1% more often in the far-transfer scenarios. Both effects were highly significant, and the difference between them was not close to significant. Thus results from tests on a simulator have a close correspondence with those in the field.

Buffering social influence: Neural correlates of response inhibition predict driving safety in the presence of a peer

Adolescence is a period characterized by increased sensitivity to social cues, as well as increased risk-taking in the presence of peers. For example, automobile crashes are the leading cause of death for adolescents, and driving with peers increases the risk of a fatal crash. Growing evidence points to an interaction between neural systems implicated in cognitive control and social and emotional context in predicting adolescent risk. We tested such a relationship in recently licensed teen drivers. Participants completed an fMRI session in which neural activity was measured during a response inhibition task, followed by a separate driving simulator session 1 week later. Participants drove alone and with a peer who was randomly assigned to express risk-promoting or risk-averse social norms. The experimentally manipulated social context during the simulated drive moderated the relationship between individual differences in neural activity in the hypothesized cognitive control network (right inferior frontal gyrus, BG) and risk-taking in the driving context a week later. Increased activity in the response inhibition network was not associated with risk-taking in the presence of a risky peer but was significantly predictive of safer driving in the presence of a cautious peer, above and beyond self-reported susceptibility to peer pressure. Individual differences in recruitment of the response inhibition network may allow those with stronger inhibitory control to override risky tendencies when in the presence of cautious peers. This relationship between social context and individual differences in brain function expands our understanding of neural systems involved in top–down cognitive control during adolescent development.

The effect of male teenage passengers on male teenage drivers: findings from a driving simulator study.

Studies have shown that teenage drivers are less attentive, more frequently exhibit risky driving behavior, and have a higher fatal crash risk in the presence of peers. The effects of direct peer pressure and conversation on young drivers have been examined. Little is known about the impact on driving performance of the presence of a non-interacting passenger and subtle modes of peer influence, such as perceived social norms. The goal of this study was to examine if teenagers would engage in more risky driving practices and be less attentive in the presence of a passenger (vs. driving alone) as well as with a risk-accepting (vs. risk-averse) passenger. A confederate portrayed the passengers characteristics mainly by his non-verbal attitude. The relationship between driver characteristics and driving behavior in the presence of a passenger was also examined. Thirty-six male participants aged 16-17 years old were randomly assigned to drive with a risk-accepting or risk-averse passenger. Main outcomes included speed, headway, gap acceptance, eye glances at hazards, and horizontal eye movement. Driver characteristics such as tolerance of deviance, susceptibility to peer pressure, and self-esteem were measured. Compared to solo driving, the presence of a passenger was associated with significantly fewer eye glances at hazards and a trend for fewer horizontal eye movements. Contrary to the hypothesis, however, Passenger Presence was associated with waiting for a greater number of vehicles to pass before initiating a left turn. Results also showed, contrary to the hypothesis, that participants with the risk-accepting passenger maintained significantly longer headway with the lead vehicle and engaged in more eye glances at hazards than participants with the risk-averse passenger. Finally, when driving with the passenger, earlier initiation of a left turn in a steady stream of oncoming vehicles was significantly associated with higher tolerance of deviance and susceptibility to peer pressure, while fewer eye glances at hazards was linked to lower self-esteem. While the results of this study were mixed, they suggest that the presence of a teenage passenger can affect some aspects of teenage driver behavior even in the absence of overt pressure and distraction. Results are discussed in relation to theoretical concepts of social influence and social facilitation models.

Naturalistic Teenage Driving Study: Findings and Lessons Learned

INTRODUCTION This paper summarizes the findings on novice teenage driving outcomes (e.g., crashes and risky driving behaviors) from the Naturalistic Teenage Driving Study. METHOD Survey and driving data from a data acquisition system (global positioning system, accelerometers, cameras) were collected from 42 newly licensed teenage drivers and their parents during the first 18 months of teenage licensure; stress responsivity was also measured in teenagers. RESULT Overall teenage crash and near-crash (CNC) rates declined over time, but were >4 times higher among teenagers than adults. Contributing factors to teenage CNC rates included secondary task engagement (e.g., distraction), kinematic risky driving, low stress responsivity, and risky social norms. CONCLUSIONS The data support the contention that the high novice teenage CNC risk is due both to inexperience and risky driving behavior, particularly kinematic risky driving and secondary task engagement. PRACTICAL APPLICATIONS Graduated driver licensing policy and other prevention efforts should focus on kinematic risky driving, secondary task engagement, and risky social norms.

Backing collisions: a study of drivers' eye and backing behaviour using combined rear-view camera and sensor systems

Context Backing crash injures can be severe; approximately 200 of the 2,500 reported injuries of this type per year to children under the age of 15 years result in death. Technology for assisting drivers when backing has limited success in preventing backing crashes. Objectives Two questions are addressed: Why is the reduction in backing crashes moderate when rear-view cameras are deployed? Could rear-view cameras augment sensor systems? Design 46 drivers (36 experimental, 10 control) completed 16 parking trials over 2  days (eight trials per day). Experimental participants were provided with a sensor camera system, controls were not. Three crash scenarios were introduced. Setting Parking facility at UMass Amherst, USA. Subjects 46 drivers (33 men, 13 women) average age 29 years, who were Massachusetts residents licensed within the USA for an average of 9.3  years. Interventions Vehicles equipped with a rear-view camera and sensor system-based parking aid. Main Outcome Measures Subjects eye fixations while driving and researchers observation of collision with objects during backing. Results Only 20% of drivers looked at the rear-view camera before backing, and 88% of those did not crash. Of those who did not look at the rear-view camera before backing, 46% looked after the sensor warned the driver. Conclusions This study indicates that drivers not only attend to an audible warning, but will look at a rear-view camera if available. Evidence suggests that when used appropriately, rear-view cameras can mitigate the occurrence of backing crashes, particularly when paired with an appropriate sensor system.

A simulator evaluation of the effects of attention maintenance training on glance distributions of younger novice drivers inside and outside the vehicle

Driver distraction inside and outside the vehicle is increasingly a problem, especially for younger drivers. In many cases the distraction is associated with long glances away from the forward roadway. Such glances have been shown to be highly predictive of crashes. Ideally, one would like to develop and evaluate a training program which reduced these long glances. Thus, an experiment was conducted in a driving simulator to test the efficacy of a training program, FOCAL, that was developed to teach novice drivers to limit the duration of glances that are inside the vehicle while performing an in-vehicle task, such as looking for a CD or finding the 4-way flashers. The test in the simulator showed that the FOCAL trained group performed significantly better than the placebo trained group on several measures, notably on the percentage of within-vehicle glances that were greater than 2, 2.5, and 3 s. However, the training did not generalize to glances away from the roadway (e.g., when drivers were asked to attend to a sign adjacent to the roadway, both trained and untrained novice drivers were equally likely to make especially long glances at the sign).

Effect of external distractions

Distractions are a major contributor to automobile crashes, almost one-third of which are thought to be caused by distractions external to the vehicle. Increasingly, external distractions include video billboards, marquees, and variable message signs placed above and beside the highway. It is known that distractions outside the vehicle, especially video billboards, have effects on various vehicle control measures, such as the minimum headway distance to a braking lead vehicle, and that novice drivers and experienced drivers spend equally long times looking at distractions outside the vehicle. In contrast, experienced drivers are much less likely than novice drivers to take long glances at distractions inside the vehicle. This finding raises two questions. First, why are experienced drivers taking such long glances at an external distraction when they are not willing do so when a secondary task arises inside the vehicle? Second, if experienced drivers are sacrificing some of their ability to monitor visible hazards in the roadway ahead, are they sacrificing even more of their ability to anticipate unseen hazards? An experiment to evaluate these two questions had novice and experienced drivers perform an external search task (similar to reading a digital billboard) while driving in a simulator. Monitored throughout were eye movements of the participants and measures of the vehicle, such as lane position and speed. The major finding was that the long glances of both experienced and novice drivers came at the cost of identifying potential hidden hazards and seeing exposed moving threats.

Explanations and Expectations: Trust Building in Automated Vehicles

Trust is a vital determinant of acceptance of automated vehicles (AVs) and expectations and explanations are often at the heart of any trusting relationship. Once expectations have been violated, explanations are needed to mitigate the damage. This study introduces the importance of timing of explanations in promoting trust in AVs. We present the preliminary results of a within-subjects experimental study involving eight participants exposed to four AV driving conditions (i.e. 32 data points). Preliminary results show a pattern that suggests that explanations provided before the AV takes actions promote more trust than explanations provided afterward.

Trust in AV: An Uncertainty Reduction Model of AV-Pedestrian Interactions

Autonomous vehicles (AVs) have the potential to improve road safety. Trust in AVs, especially among pedestrians, is vital to alleviate public skepticism. Yet much of the research has focused on trust between the AV and its driver/passengers. To address this shortcoming, we examined the interactions between AVs and pedestrians using uncertainty reduction theory (URT). We empirically verified this model with a user study in an immersive virtual reality environment (IVE). The study manipulated two factors: AV driving behavior (defensive, normal and aggressive) and the traffic situation (signalized and unsignalized). Results suggest that the impact of aggressive driving on trust in AVs depends on the type of crosswalk. At signalized crosswalks the AV»s driving behavior had little impact on trust, but at unsignalized crosswalks the AV»s driving behavior was a major determinant of trust. Our findings shed new insights on trust between AVs and pedestrians.