On-road study investigating the mode of feedback delivery on young drivers’ speed management

Feedback has been shown to be instrumental in learning. Refining how it is delivered in driver training has the potential to reduce crash risk. Therefore, the aim of the present study was to examine the effect of the medium in which feedback is delivered (verbal, written, graphical) on young drivers’ speed management behaviour. Sixty young drivers, randomly allocated to one of four feedback groups (i.e., Control, Verbal feedback, Written feedback, and Graphical feedback) completed one training and two test drives using an instrumented vehicle on-road. After the first (baseline) drive, participants were provided feedback about the number of times they exceeded the speed limit, their maximum speed, as well as the financial penalties associated with such driving behaviour, and safety implications. The content of feedback remained the same for all training groups, except for the manner in which the feedback was presented. Verbal feedback was provided verbally by the researcher; written feedback on paper; and graphical feedback using a series of graphs on a computer screen. Control received no such intervention. Two test drives followed, one immediate post-training, and the second one week post-training. Feedback, irrespective of medium improved young drivers’ speed management. Verbal and graphical feedback yielded the greatest reduction in speeding behaviour, with graphical feedback having the most impact in the two speed zones under examination (50 km/h & 80 km/h). Control showed the poorest speed management behaviour in all drives. These findings have important implications for the development of a new approach to improve young drivers’ speed management behaviour.     

Influence of following vehicle’s tailway and classification on subject driver’s response to the circular yellow indication

Traffic crashes at signalized intersections are frequently linked to driver behavior at the onset of the circular yellow (CY) indication. To better understand behavioral factors that influence a driver’s decision to stop or go at an intersection, this study analyzed the behavior of the driver of a subject vehicle at the onset of the CY indication. Driver performance data from 53 participants were collected in the Oregon State University Driving Simulator, simulating scenarios of driving through high-speed intersections under various conditions. Data included interactions where the driver stopped at the stop line (n = 644) or proceeded through the intersection (n = 628) in response to a CY indication. Data were analyzed as panel data while considering 12 indicator variables related to the driver’s stop/go decision. These indicator variables included time to stop line (TTSL), tailway time, following vehicle type, vehicle speed at the onset of the CY indication, and demographics (age, gender, driving experience, level of education, personal vehicle type, number of times driving per week, number of miles driving last year, participation in previous simulation studies. A random-parameter binary logit model was used to determine contributing factors for driver decision making at the onset of CY indication while accounting for unobserved heterogeneity. Four indicator variables were significantly related to the driver’s stop/go decision, but three factors varied across observations. Findings showed that a driver’s stop/go decision in response to a CY indication was associated with the time to the stop line (TTSL), tailway time to the following vehicle, subject vehicle speed at the onset of the CY indication, and driver’s age (20–36 years), but was not significantly associated with classification of the following vehicle. Also, the findings indicated that a shorter tailway increased a subject driver’s red-light running frequency. These findings provide insights into variables that affect driver decisions in a vehicle-following situation at the onset of the CY indication. This information can help make better decisions in smart traffic control systems such as to extend/decrease the green interval slightly to avoid decisions that are more difficult.     

Effects of forward collision warning technology in different pre-crash scenarios

The forward collision warning (FCW) system is expected to reduce rear-end crashes; however, its effects on driving behavior and safety have not been thoroughly investigated, specifically the effect variations between different pre-crash scenarios. To identify these variations, this study conducted a driving simulator experiment and compared the FCW’s effects between three pre-crash scenarios: the freeway scenario, the arterial scenario and the intersection dilemma zone scenario. Thirty-nine participants were involved in the experiment. The results showed that the adaptation of driver behavior in impending rear-end collision events resulted from both the FCW and the scenario. The intersection dilemma zone scenario has indications of slowing down, which encouraged drivers to take a more aggressive response strategy under the FCW; the arterial scenario might be regarded as an “easy-to-handle” situation in which a significant portion of drivers adopted moderate level of response strategy under the FCW; both the intersection dilemma zone scenario and freeway scenario have burdened driving tasks, and this might deteriorate a driver’s ability to adapt to the FCW. In addition, different types of drivers experienced varied benefits from the FCW in each scenario. The FCW would be particularly recommended for non-experienced drivers in the freeway scenario and for female drivers in the arterial scenario; moreover, in the scenario of the intersection dilemma zone, the FCW would be particularly recommended for drivers who have a crash/citation before. The results also support specific FCW designs which are able to highlight the collision risk. This study demonstrated that it would be better to indicate the effects of the FCW under the restriction of specific scenario features and develop the FCW based on that.     

Effects of speed feedback signs and law enforcement on driver speed

This study analyzes the effects of implementing three speed management strategies, namely speed feedback signs, periodic law enforcement, and speed feedback sign supported with periodic law enforcement on driver speed behavior and compliance. To analyze the effectiveness of each strategy, nine locations in Pima County, Arizona, were studied in a cross-sectional framework. For each study site, the driver’s speed, date, time, and vehicle’s length were collected at a location prior to the speed management zone as the baseline, at the speed management zone, and downstream of the speed management zone. The general effect showed that all the strategies were effective in reducing average speed and the proportion of drivers exceeding the speed limit. In addition, the results of the robust heteroscedastic ANOVA test showed that among all the strategies, the speed feedback sign supported with periodic law enforcement was the most effective one. Moreover, it was shown that by supporting the speed feedback sign with periodic law enforcement, the reduction in average speed and proportion of drivers exceeding the speed limit would last, even after passing the speed management strategy. In other words, the existence of periodic law enforcement could potentially modify drivers’ behaviors and increase the spatial effectiveness of speed feedback signs. Comparing the behavior of truck and passenger car drivers also revealed similar results. That is, both truck and passenger car drivers tend to slow down after observing the speed management strategy. The experimental evidence indicates positive benefits for reducing excessive speeding behaviors at the sites.     

Driver conflict response during supervised automation: Do hands on wheel matter?

Securing appropriate driver responses to conflicts is essential in automation that is not perfect (because the driver is needed as a fall-back for system limitations and failures). However, this is recognized as a major challenge in the human factors literature. Moreover, in-depth knowledge is lacking regarding mechanisms affecting the driver response process. The first aim of this study was to investigate how driver conflict response while using highly reliable (but not perfect) supervised automation differ for drivers that (a) crash or avoid a conflict object and (b) report high trust or low trust in automation to avoid the conflict object. The second aim was to understand the influence on the driver conflict response of two specific factors: a hands-on-wheel requirement (with vs. without), and the conflict object type (garbage bag vs. stationary vehicle). Seventy-six participants drove with highly reliable but supervised automation for 30 min on a test track. Thereafter they needed to avoid a static object that was revealed by a lead-vehicle cut-out. The driver conflict response was assessed through the response process: timepoints for driver surprise reaction, hands-on-wheel, driver steering, and driver braking. Crashers generally responded later in all actions of the response process compared to non-crashers. In fact, some crashers collided with the conflict object without even putting their hands on the wheel. Driver conflict response was independent of the hands-on-wheel requirement. High-trust drivers generally responded later than the low-trust drivers or not at all, and only high trust drivers crashed. The larger stationary vehicle triggered an earlier surprise reaction compared to the garbage bag, while hands-on-wheel and steering response were similar for the two conflict object types. To conclude, crashing is associated with a delay in all actions of the response process. In addition, driver conflict response does not change with a hands-on-wheel requirement but changes with trust-level and conflict object type. Simply holding the hands on the wheel is not sufficient to prevent collisions or elicit earlier responses. High trust in automation is associated with late response and crashing, whereas low trust is associated with appropriate driver response. A larger conflict object trigger earlier surprise reactions.     

Sexual activity while driving: A content analysis of media reports

Sexual activity while driving fits the definition of distracted driving because it involves the diversion of attention away from the driving task. However, this risky driving behaviour has received little attention compared to other distracted driving activities. To address the lack of research on sexual activity while driving, the internet was searched from April to June 2020 for media reports in which sexual activities occurred within the cabin of a moving vehicle, taking specific note of: gender, the presence of others, time of day, use of substances, the nature of the circumstances surrounding the incident, and whether crashes had occurred. A total of 106 unique and verified cases were identified from 2004 to 2020. The reports involved 76 male (71.7%) and 30 female drivers (28.3%), and there were 43 (40.5%) serious incidents that involved a crash and 23 fatalities (21.7%). In 17 (16.0%) incidents their vehicle hit another car, and a pedestrian or cyclist was hit in 3 (2.8%) incidents. The risk of a serious incident was higher during oral sex or intercourse than solitary activities (i.e. masturbation). A total of 63 (59.5%) mild incidents (without crashes or fatalities) were identified, in which reports included accounts by witnesses or police regarding sexual activity while driving. Given the potential seriousness of incidents, this topic deserves further research to better understand the prevalence and safety implications of sexual activity while driving.     

Evaluating driver comprehension of the roadway environment to retain accountability of safety during driving automation

Driver comprehension is a substantial component of situation awareness that involves the ability of an individual to understand the significance of an object, traffic sign, or hazard while driving. An increase in crashes related to autonomous driving systems has raised a concern regarding the safety of other roadway users due to the diminishing accountability resulting from a general lack of understanding of the limitations or disregard of the safety protocols by users. To keep drivers vigilant when engaged in partial automated systems, a methodology to monitor real-time driver comprehension was proposed. A driving simulator study consisting of 90 participants, equally split between males and females, was executed to establish driver comprehension in six different variations of driving difficulty. Joint probability density functions were created by considering percent time spent gazing, answers to probe questions, and driving performance. Based on these density functions, five levels of comprehension were devised and assigned thresholds. Overall, as task difficulty increased, a non-linear deterioration in driving speed along with an increase in total gaze duration was observed before comprehension was attained. A two-step validation protocol was also proposed to ensure similar levels of comprehension to non-automated driving from the human driver, when engaged in early forms of automation. The proposed real-time driver comprehension monitoring constitutes a first step toward developing a methodology to reinstate the accountability of safety of other roadway users when engaged in driver-in-the-loop automation systems.     

Student driver propensity to engage with distractions – a self-report survey

This paper reports a survey of engagement with, and ratings of, driver distraction, for undergraduate student drivers. Survey data was collected using an anonymous online questionnaire. 530 respondents contributed to the survey during a seven-year data collection period.Results indicate that the three internal-to-vehicle behaviours rated as most distracting when driving were ‘writing text messages’, ‘internet use’, and ‘reading text messages’. The three most frequently undertaken distractions were, ‘(interactions with) adults’, ‘daydreaming’, and ‘eating, drinking or smoking’. Considering external-to-vehicle distractions, the top three rated were ‘environmental conditions’, ‘unexpected objects or events’, and ‘animals behaving unexpectedly’; while the most frequently experienced external distractions were ‘people (behaving normally), ‘busy roads’ and ‘official signage’. Some evidence was found that internal-to-vehicle distractions were relatively more distracting than external-to-vehicle ones, along with limited findings showing significant variation in the amount of engagement with distractions over time. Significant predictive models for engagement with distraction were calculated (for both work-related and non-work-related driving) and found to be broadly in agreement with previous research, although accounting for less variance in the models. Significantly greater engagement with distractions was found during non-work-related driving, when compared to work-related.The data present a picture of ongoing and substantial engagement with distracting behaviours for this population over the data collection period. For example, on a daily or weekly basis, more than three-fifths of respondents reported willingness to read text messages with the vehicle in motion; while just under half indicated that they typically write text messages in the same circumstances. However, the findings do offer some promise that interventions targeted towards non-work-related driving behaviours may be effective to reduce volitional engagement with distractions.     

From sport to eco: A case study of driver inputs on electric vehicle efficiency

This study focuses on driver-induced changes to vehicle energy and emissions performance by altering drivetrain configurations. It defines and examines the motivations for the use of drive modes in plug-in hybrid electric vehicles (PHEVs). Drive modes are defined as user-selectable drivetrain configurations that allow drivers to change vehicle performance aspects such as altering its propulsion status from electric to gas, changing the steering responsiveness, suspension stiffness, and regenerative braking strength. Despite the direct impact they have on the vehicle’s energy usage, greenhouse gas emissions, and local air emissions, the impact of drive modes are not traditionally measured as part of the vehicle’s performance and certification tests. The impact of drive mode choice can explain a portion of the discrepancy between PHEVs expected and on road performance as a recent study by the authors found that the use of certain modes can result in a 15–30% increase in total energy usage in a vehicle traveling at freeway speeds.This is the first study to examine the motivations for the use of these drive modes and provides an overview of PHEV drive modes, classifying them into two main mode categories (propulsion adjustment and driver experience) and eight different mode types based on their intended purpose. This is followed by a logistic regression of 11 indicators for mode usage taken from a survey of over 4,500 PHEV owning households, showing that gender and the number of long-distance trips were the most commonly associated with usage across mode types.     

Comparing skill acquisition under varying onsets of differential reinforcement: A preliminary analysis

The purpose of the current study was to evaluate the effect of implementing differential reinforcement at different times relative to the onset of teaching new skills to learners with autism spectrum disorder. Specifically, we first determined the most efficient differential reinforcement arrangement for each participant. Using the most efficient arrangement, we evaluated if differential reinforcement from the immediate onset, early onset, or late onset is the most efficient for learners to acquire a new skill. Three children diagnosed with autism spectrum disorder who have a history of receiving intervention based on the principles of applied behavior analysis participated in this study. The immediate onset of differential reinforcement resulted in the most efficient instruction in 6 of 7 comparisons. The results are discussed in light of previous studies and suggestions for future research are provided.