Motivating signage prompts safety belt use among drivers exiting senior communities

Senior drivers are vulnerable to automobile crashes and subsequent injury and death. Safety belts reduce health risks associated with auto crashes. Therefore, it is important to encourage senior drivers to wear safety belts while driving. Using an AB design, replicated five times, we evaluated the short- and long-term effects of a sign with the message "BUCKLE UP, STAY SAFE" attached to a stop sign at the exits of five different senior communities. Safety belt use was stable during two pretreatment assessments averaged across the five sites and 250 drivers (72% and 68% usage), but significantly increased following installation of these signs (94% usage). Six months after installation of the signs, the effect persisted (88% usage). Use of such signs may be a cost-effective way of promoting safety belt use.     

Comprehensive driving assessment: neuropsychological testing and on-road evaluation of brain injured patients

The study investigates the correspondence between neuropsychological test results and on-road driving performance among 55 patients with a CT-verified brain damage or documented neurological disorder (cerebrovascular accident: 43, traumatic brain injury: 5, multiple sclerosis: 4, other: 3). 5 patients showed unimpaired test profiles and passed the on-road evaluation. 18 patients showed severe neuropsychological deficits contrary to driving and were not recommended for on-road evaluation. Of the remaining 32 patients with some neuropsychological deficits, all 100% in the minor impaired group (n = 8) passed the driving evaluation, compared to 69% in the mildly impaired (n = 16) and 38% in the moderately impaired group (n = 8). Measures of reduced visuoconstructive ability, reaction time, visual attention, and awareness of cognitive impairments, were found to discriminate between groups. It is concluded that neuropsychological assessment of targeted functions provide an ecological valid prediction of driving skill after brain damage, but that on-road evaluation is needed as supplement in cases with ambiguous test findings.     

A company-based lottery to reduce the personal driving of employees

A company-based lottery was used to reduce the number of nonessential miles employees drove their personal cars each day and thereby save gasoline. Employees were divided into an experimental and a contrast group. The experimental design involved two conditions: (a) a baseline in which no consequences were attached to driving behavior, and (b) a month-long lottery in which the experimentals were rewarded for decreasing their percentage of average miles driven per day relative to their initial baseline average. The experimentals received an ABA order of conditions while the contrast group remained in baseline. The lottery condition consisted of four weekly lotteries and one grand drawing held at the end of the month. During the lottery condition, the experimentals reduced their average daily mileage by 11.6% relative to their initial baseline (7.85 miles per employee per day) while the contrast employees increased their average mileage by 21.2%. Both groups exceeded their initial baseline averages in the return to baseline. The study was almost cost-effective because the experimentals' gas savings ($75) was within $4 of the cost of motivating them to reduce their mileage ($79).     

Road-sign utility as judged by drivers with different amounts of driving experience

This study starts from the hypothesis that sign perception depends on the motivational valences of signs. Two groups of drivers with different amounts of driving experience rated Swedish road signs on dimensions assumed to indicate perceived sign utility. The ratings were performed against a scenario that included traffic officials' intentions to simplify the sign system. One dimension was amount of reduction in frequency of occurrence; subjects indicated percentages of reduction they believed to be reasonable. A second dimension was appropriateness of complete elimination of a sign from the traffic environment; subjects rated the degree to which elimination was reasonable. Subjective frequency of sign occurrence was rated last. Construct validation procedures showed strong correlations between reduction and elimination ratings only for the higher-experience group. Contrary to expectation, both groups showed the same high level of positive attitudes toward all signs. As expected, frequency was a judgmental base for utility, though weakly, except for permissive signs. It was more extensively related to utility for the higher-experience group, particularly for percentage ratings. Curvilinear relationships obtained between frequency and utility for permissive and road guidance signs.     

Prediction of effort and eye movement measures from driving scene components

For transitions of control in automated vehicles, driver monitoring systems (DMS) may need to discern task difficulty and driver preparedness. Such DMS require models that relate driving scene components, driver effort, and eye measurements. Across two sessions, 15 participants enacted receiving control within 60 randomly ordered dashcam videos (3-second duration) with variations in visible scene components: road curve angle, road surface area, road users, symbols, infrastructure, and vegetation/trees while their eyes were measured for pupil diameter, fixation duration, and saccade amplitude. The subjective measure of effort and the objective measure of saccade amplitude evidenced the highest correlations (r = 0.34 and r = 0.42, respectively) with the scene component of road curve angle. In person-specific regression analyses combining all visual scene components as predictors, average predictive correlations ranged between 0.49 and 0.58 for subjective effort and between 0.36 and 0.49 for saccade amplitude, depending on cross-validation techniques of generalization and repetition. In conclusion, the present regression equations establish quantifiable relations between visible driving scene components with both subjective effort and objective eye movement measures. In future DMS, such knowledge can help inform road-facing and driver-facing cameras to jointly establish the readiness of would-be drivers ahead of receiving control.     

A driving simulator study to assess driver performance during a car-following maneuver after switching from automated control to manual control

A review of the literature on autonomous vehicles has shown that they offer several benefits, such as reducing traffic congestion and emissions, and improving transport accessibility. Until the highest level of automation is achieved, humans will remain an important integral of the driving cycle, which necessitates to fully understand their role in automated driving. A difficult research topic involves an understanding of whether a period of automated driving is likely to reduce driver fatigue rather than increase the risk of distraction, particularly when drivers are involved in a secondary task while driving. The main aim of this research comprises assessing the effects of an automation period on drivers, in terms of driving performance and safety implications. A specific focus is set on the car-following maneuver. A driving simulator experiment has been designed for this purpose. In particular, each participant was requested to submit to a virtual scenario twice, with level-three driving automation: one drive consisting of Full Manual Control Mode (FM); the other comprising an Automated Control Mode (AM) activated in the midst of the scenario. During the automation mode, the drivers were asked to watch a movie on a tablet inside the vehicle. When the drivers had to take control of the vehicle, two car-following maneuvers were planned, by simulating a slow-moving vehicle in the right lane in the meanwhile a platoon of vehicles in the overtaking lane discouraged the passing maneuver. Various driving performances (speeds, accelerations, etc.) and surrogate safety measures (PET and TTC) were collected and analysed, focusing on car-following maneuvers. The overall results indicated a more dangerous behavior of drivers who were previously subjected to driving automation; the percentage of drivers who did not apply the brakes and headed into the overtaking lane despite the presence of a platoon of fast-moving vehicles with unsafe gaps between them was higher in AM drive than in FM drive. Conversely, for drivers who preferred to brake, it was noted that those who had already experienced automated driving, adopted a more careful behavior during the braking maneuver to avoid a collision. Finally, with regard to drivers who had decided to overtake the braking vehicle, it should be noted that drivers who had already experienced automated driving did not change their behavior whilst overtaking the stopped lead vehicle.     

The utility of psychological measures in evaluating perceived usability of automated vehicle interfaces – A study with older adults

The design of the traditional vehicle human-machine interfaces (HMIs) is undergoing major change as we move towards fully connected and automated vehicles (CAVs). Given the diversity of user requirements and preferences, it is vital for designers to gain a deeper understanding of any underlying factors that could impact usability. The current study employs a range of carefully selected psychological measures to investigate the relationship with self-report usability of an in-CAV HMI integrated into a fully automated Level 5 simulator, during simulated journeys. Twenty-five older adults (65-years+) participated and were exposed to four journeys in a virtual reality fully automated CAV simulator (with video recorded journeys) into which our HMI was integrated. Participants completed a range of scales and questionnaires, as well as computerized cognitive tests. Key measures were: perceived usability of the HMI, cognitive performance, personality, attitudes towards computers, trust in technology, simulator sickness, presence and emotion. HMI perceived usability correlated positively with cognitive performance (e.g., working memory) and some individual characteristics such as trust in technology and negatively with neuroticism anxiety. Simulator sickness was associated negatively with CAV HMI perceived usability. Positive emotions correlated positively with reported usability across all four journeys, while negative emotions were negatively associated with usability only in the case of the last two journeys. Increased sense of presence in the virtual CAV simulator was not associated with usability. Implications for design are critically discussed. Our research is highly relevant in the design of high-fully automated vehicle HMIs, particularly for older adults, and in informing policy-makers and automated mobility providers of how to improve older people’s uptake of this technology.     

Evaluating the effectiveness of a young driver-education intervention: Learn2Live

Road traffic collisions are the leading cause of death among young adults, and behaviour change interventions play a key role in battling this public health concern. Road safety interventions are often educational and have traditionally relied on fear appeals to alter risky driving behaviour - yet there is a paucity of data regarding their effectiveness. Peer-education has been championed as an additional route to promoting safe driving behaviour. To examine these issues, this study evaluated the effectiveness of a fear appeal intervention in improving young drivers’ attitudes towards risky driving behaviour. A total sample of 800 high school and college students (16–20 years old) completed a similar set of questionnaires pre- and post-intervention and at a 3-month follow-up. Two different types of follow-up interventions were also compared: a peer-led and an expert-led road safety educational event. Measures evaluating attitudes towards risky driving behaviour were completed at all 3 time frames, and questions regarding the participants' perception of the follow-up event were asked. Overall, our data showed an improvement in attitudes towards risky driving behaviours both immediately after the intervention and three months later. These changes were especially evident among females. With regard to the follow-ups, both were effective in improving the attitudes towards risky driving. However, the peer-led event was preferred by the participants compared to the expert-led follow-up.     

Using a multi-user driving simulator system to explore the patterns of vehicle fleet rear-end collisions occurrence under different foggy conditions and speed limits

Vehicle fleet rear-end collisions (FRECs) are an extremely fatal type of traffic collisions on freeway and they usually occur in foggy weather. This study aimed to explore the patterns of vehicle fleet rear-end collisions occurrence under different foggy conditions and speed limits on freeway. A multi-user driving simulator system was used to conduct the experiment and the driving behavior data were collected from eight participants. The experimental results showed that as the fog density increased, the length of vehicle fleet decreased significantly, and drivers tended to keep a more stable car-following distance. The fog weather and short vehicle gap prompted drivers to react faster and brake harder in respond to the leading vehicle’s brake. In spite of the compensational behaviors, more FRECs were observed under heavy fog condition. Lowering speed limit can significantly reduce the FRECs under foggy conditions. As the speed limits reduced, drivers’ brake response time and speed variance significantly reduced. The study also found that drivers’ brake response time was negatively correlated with their positions in the fleet. Drivers in the front positions of the fleet had a longer response time than drivers in the back positions and thus were more likely to encounter collisions. The study generated a better understanding of drivers’ behavioral pattern in a vehicle fleet and the patterns of vehicle fleet rear-end collisions occurrence. The findings also shed lights on the design of driver assistance system for complex driving situations such as freeway driving under adverse weather.