Driving performance comparing older versus younger drivers

Exploring the acute and chronic effects of a multi-strain probiotic supplement on cognitive function and mood in healthy older adults: A randomised controlled trial

BACKGROUND

Ageing, is associated with a decline in cognitive function and vulnerability to depression. Probiotic supplements have shown beneficial effects on cognition and mood in clinical populations, but the potential benefit for healthy older adults experiencing age-related decline in cognition remains unclear.

OBJECTIVES

The primary aim of the present work was to explore the effect of a chronic (long-term) multi-species probiotic intervention on cognition in healthy ageing adults. Secondary aims included exploring the chronic effect on mood outcomes and gut microbiota community, as well as a novel investigation into the acute effect of supplementation on cognition and mood.

METHOD

The study employed a randomised, placebo-controlled, cross-over trial in 30 healthy older adults to explore the acute (1 day) and chronic (8 weeks) effects of a probiotic supplement on cognitive domains of memory and executive function, alongside mood measures of stress, anxiety, depression, and cognitive reactivity to sad mood. 16s rRNA sequencing of stool samples was also performed pre- and post- chronic intervention to assess potential effects on the gut microbiota.

RESULTS

Acute probiotic supplementation was associated with faster reaction times on cognitively demanding trials during a task of executive function [-64.91ms, CI -115.70, -14.15]. Chronic supplementation was associated with improvement in cognitive biases such as hopelessness [-0.97, CI -1.72, -0.23], rumination [-1.58, CI -2.86, -0.29] and aggression [-1.57, CI -2.63, -0.51] that contribute to reactivity to sad mood and therefore vulnerability to depression, and may improve executive function under higher cognitive demand [0.43%, CI -0.53%, 1.38%].

CONCLUSIONS

The current work provides novel evidence for an acute effect of probiotics on reaction times during executive function, which should be replicated in future work. Additionally, this work replicates previous findings of improved cognitive reactivity to sad mood following chronic probiotic supplementation, indicating probiotics may reduce the risk of developing depression in a healthy ageing population. This trial was registered at https://clinicaltrials.gov/study/NCT04951687.

Pilot Study on Gaze Characteristics of Older Drivers While Watching Driving Movies

Objective: This study aims to clarify the gazing characteristics of older drivers while driving cars using a gaze analysis device. Methods: The participants included 16 older and 12 middle-aged drivers who drove cars daily. After conducting cognitive and attentional function tests, eye gaze while watching driving videos was measured using an eye tracker. Ten driving videos were prepared. In addition, a total of 34 hazard areas were analyzed. Results: The results of the gaze measurement parameters were statistically compared between the two groups. In the older group, the gaze analysis results indicated that while viewing driving videos, the search for areas close to the car was expanded. In addition, in several hazard areas, we observed a decrease in the number of drivers gazing at the driver, shortened total gazing time, delay in the timing of gazing, and decrease in the number of visits. Conclusions: Older drivers' eye movement is increased; however, it is characterized by gazing at unimportant areas, indicating an inefficient scanning pattern. Although these results do not indicate an obvious decline in driving ability among older drivers, the decline in hazard perception may become apparent in some situations. The data contain underpowered results and require revalidation in larger studies.

Older adult driving performance assessed under simulated and on-road conditions

Simulated driving offers a convenient test of driving ability for older drivers, although the viability of using simulated driving with this population is mixed. The relative weighting of the relevant perceptual, cognitive, and physical factors may vary between simulated and on-road driving. The current study was designed to assess this possibility. We conducted simulated and on-road driving tests of 61 older adults aged 66-92 years. To ensure that the driving performance was measured similarly between the two driving modalities, we employed the Record of Driving Errors (RODE) driving assessment system during both driving tests. Correlation and random weights analysis (RWA) results indicated only modest evidence of correspondence between the simulated and on-road driving performances. The primary factors operative in both simulated and on-road driving was Useful Field of View and a measure of basic cognition. Unique factors for simulated driving included a measure of physical mobility (Time-Up-and-Go) and spatial reasoning (Line), and for on-road driving included chronological age and sensorimotor processing (Trail-Making Task A). Chronological age was correlated primarily the on-road rather than simulated test, was greatly reduced with the inclusion of additional explanatory factors, and likely reflects driving efficiency rather than driving safety. We conclude that simulated driving in healthy older drivers can be beneficial for research purposes to assess cognitive and perceptual factors that underly driving effectiveness, although it cannot serve as a clear proxy for on-road driving.

The effect of cannabis edibles on driving and blood THC

BACKGROUND

Cannabis has been shown to impact driving due to changes produced by delta-9-tetrahydrocannabinol (THC), the psychoactive component of cannabis. Current legal thresholds for blood THC while driving are based predominantly on evidence utilizing smoked cannabis. It is known that levels of THC in blood are lower after eating cannabis as compared to smoking yet the impact of edibles on driving and associated blood THC has never been studied.

METHODS

Participants drove a driving simulator before and after ingesting their preferred legally purchased cannabis edible. In a counterbalanced control session, participants did not consume any THC or cannabidiol (CBD). Blood was collected for measurement of THC and metabolites as well as CBD. Subjective experience was also assessed.

RESULTS

Participants consumed edibles with, on average, 7.3 mg of THC, which is less than the maximum amount available in a single retail package in Ontario, providing an ecologically valid test of cannabis edibles. Compared to control, cannabis edibles produced a decrease in mean speed 2 h after consumption but not at 4 and 6 h. Under dual task conditions in which participants completed a secondary task while driving, changes in speed were not significant after the correction for multiple comparison. No changes in standard deviation of lateral position (SDLP; 'weaving'), maximum speed, standard deviation of speed or reaction time were found at any time point or under either standard or dual task conditions. Mean THC levels were significantly increased, relative to control, after consuming the edible but remained relatively low at approximately 2.8 ng/mL 2 h after consumption. Driving impairment was not correlated with blood THC. Subjective experience was altered for 7 h and participants were less willing/able to drive for up to 6 h, suggesting that the edible was intoxicating.

INTERPRETATION

This is the first study of the impact of cannabis edibles on simulated driving. Edibles were intoxicating as revealed by the results of subjective assessments (VAS), and there was some impact on driving. Detection of driving impairment after the use of cannabis edibles may be difficult.

Relationship between Driving Ability and Physical Fitness Factors in Older Adults: A Multiple Linear Regression Analysis

The number of older drivers is increasing with the aging population; this has led to concerns about traffic accidents involving older drivers. For older adults, the automobile is not just a means of transportation, but a life necessity that promotes social activities and maintains and improves health-related quality of life. In this study, we aimed to clarify the relationship between driving ability and physical fitness factors among 70 older adult drivers using a single regression analysis and multiple regression models adjusted for age, sex, and other factors. Driving ability was evaluated by driving an actual car on an ordinary road without a simulator. The single regression analysis revealed no relationship between driving ability and any physical fitness factor. In the multiple regression model analysis, only grip strength was an important explanatory factor; however, the driving ability scores decreased as grip strength scores increased. By clarifying the physical fitness factors that influence the maintenance and improvement of driving ability, it is possible to propose more efficient intervention programs to maintain and improve driving ability. We could not identify the relevant physical fitness factors in this study; therefore, further research is required to improve safe driving among older adults.

A Comparison of Night Hazard Detection between Younger and Older Drivers under Driving Simulation and Real-World Conditions

''Using eye-tracking technology, this study examined hazard detection at night. Using a 2 (younger versus older) x 2 (simulator versus on road) repeated-measures mixed design, 16 older adults and 17 younger adults drove their own vehicle and on a driving simulator under nighttime conditions wearing eye tracking technology. Both driving conditions had three roadway hazards of pedestrians looking at their cell phone while posed to cross the roadway. Pupil glances were recorded using outcome measures of total fixation duration, number of fixations, and time to first fixation. Results showed older adults detected hazards similarly to younger adults, especially during on-road performance. Night hazard detection was similar across driving conditions except for time to first fixation, which was faster on-road for both age groups. Results support potential use of driving simulators as a proxy for on-road with night driving needed for research and practice.

Cannabis and Driving in Older Adults

Importance

Epidemiological studies have found that cannabis increases the risk of a motor vehicle collision. Cannabis use is increasing in older adults, but laboratory studies of the association between cannabis and driving in people aged older than 65 years are lacking.

Objective

To investigate the association between cannabis, simulated driving, and concurrent blood tetrahydrocannabinol (THC) levels in older adults.

Design, Setting, and Participants

Using an ecologically valid counterbalanced design, in this cohort study, regular cannabis users operated a driving simulator before, 30 minutes after, and 180 minutes after smoking their preferred legal cannabis or after resting. This study was conducted in Toronto, Canada, between March and November 2022 with no follow-up period. Data were analyzed from December 2022 to February 2023.

Exposures

Most participants chose THC-dominant cannabis with a mean (SD) content of 18.74% (6.12%) THC and 1.46% (3.37%) cannabidiol (CBD).

Main outcomes and measures

The primary end point was SD of lateral position (SDLP, or weaving). Secondary outcomes were mean speed (MS), maximum speed, SD of speed, and reaction time. Driving was assessed under both single-task and dual-task (distracted) conditions. Blood THC and metabolites of THC and CBD were also measured at the time of the drives.

Results

A total of 31 participants (21 male [68%]; 29 White [94%], 1 Latin American [3%], and 1 mixed race [3%]; mean [SD] age, 68.7 [3.5] years), completed all study procedures. SDLP was increased and MS was decreased at 30 but not 180 minutes after smoking cannabis compared with the control condition in both the single-task (SDLP effect size [ES], 0.30; b = 1.65; 95% CI, 0.37 to 2.93; MS ES, -0.58; b = -2.46; 95% CI, -3.56 to -1.36) and dual-task (SDLP ES, 0.27; b = 1.75; 95% CI, 0.21 to 3.28; MS ES, -0.47; b = -3.15; 95% CI, -5.05 to -1.24) conditions. Blood THC levels were significantly increased at 30 minutes but not 180 minutes. Blood THC was not correlated with SDLP or MS at 30 minutes, and SDLP was not correlated with MS. Subjective ratings remained elevated for 5 hours and participants reported that they were less willing to drive at 3 hours after smoking.

Conclusions and relevance

In this cohort study, the findings suggested that older drivers should exercise caution after smoking cannabis.

Attribution Errors by People and Intelligent Machines

OBJECTIVE

To explore the ramifications of attribution errors (AEs), initially in the context of vehicle collisions and then to extend this understanding into the broader and diverse realms of all forms of human-machine interaction.

BACKGROUND

This work focuses upon a particular topic that John Senders was examining at the time of his death. He was using the lens of attribution, and its associated errors, to seek to further understand and explore dyadic forms of driver collision.

METHOD

We evaluated the utility of the set of Senders' final observations on conjoint AE in two-vehicle collisions. We extended this evaluation to errors of attribution generally, as applicable to all human-human, human-technology, and prospectively technology-technology interactions.

RESULTS

As with Senders and his many other contributions, we find evident value in this perspective on how humans react to each other and how they react to emerging forms of technology, such as autonomous systems. We illustrate this value through contemporary examples and prospective analyses.

APPLICATIONS

The comprehension and mitigation of AEs can help improve all interactions between people, between intelligent machines and between humans and the machines they work with.

The role of death-related advertisements in cell phone use while driving

Approximately 25% of accidents in the United States are caused by texting while driving, prompting the creation of several media campaigns to reduce such risky behavior. The current research examined whether death-related advertisements increase cell phone use while driving. Studies 1-3 found that individuals engaged in greater distracted driving in the presence of a mortality-themed texting advertisement. Study 2 demonstrated that participants were more likely to text on their cell phone using a driving simulator, leading to more swerving and collisions after viewing a death-related (vs. neutral) poster. Finally, using eye-tracking, Study 3 showed that participants who viewed a death advertisement looked away from the road and texted more as compared to persons in the control condition. Implications and future directions are discussed.

Research on driving behavior characteristics of older drivers based on drivers' behavior graphs analysis

Considerable evidence suggests that the decline in physiological abilities prevalent in older drivers leads to a reduction in the visual and psychomotor functions required for safe driving. The purpose of this study is to further investigate the differences in driving behavior between older and younger drivers and to describe the change process of driving behavior. In this study, 19 younger and older drivers each were recruited for a driving simulation experiment that included five scenarios. Driving operation data, eye movement data, and physiological data of drivers in five conflict scenarios were collected. The differences in driving behaviors between the two groups were also compared and analyzed, on which the thresholds of different driving behavior nodes were determined and driving behavior graphs were established. The results show that the eye movement nodes of older drivers appear later in five scenarios, the operational nodes of older people appear later in two steering scenarios, and are closer to those of younger drivers in three straight ahead scenarios, indicating that older drivers were later in observing and collecting traffic information, and later in applying brakes and steering to avoid conflicts when steering. The study provides a reference for the analysis of driving behavior and driving safety of older people.

Head Scanning Behavior Predicts Hazard Detection Safety Before Entering an Intersection

OBJECTIVE

We conducted a driving simulator study to investigate scanning and hazard detection before entering an intersection.

BACKGROUND

Insufficient scanning has been suggested as a factor contributing to intersection crashes. However, little is known about the relative importance of the head and eye movement components of that scanning in peripheral hazard detection.

METHODS

Eleven older (mean 67 years) and 18 younger (mean 27 years) current drivers drove in a simulator while their head and eye movements were tracked. They completed two city drives (42 intersections per drive) with motorcycle hazards appearing at 16 four-way intersections per drive.

RESULTS

Older subjects missed more hazards (10.2% vs. 5.2%). Failing to make a scan with a substantial head movement was the primary reason for missed hazards. When hazards were detected, older drivers had longer RTs (2.6s vs. 2.3s), but drove more slowly; thus, safe response rates did not differ between the two groups (older 83%; younger 82%). Safe responses were associated with larger (28.8° vs. 20.6°) and more numerous (9.4 vs. 6.6) gaze scans. Scans containing a head movement were stronger predictors of safe responses than scans containing only eye movements.

CONCLUSION

Our results highlight the importance of making large scans with a substantial head movement before entering an intersection. Eye-only scans played little role in detection and safe responses to peripheral hazards.

APPLICATION

Driver training programs should address the importance of making large scans with a substantial head movement before entering an intersection.

Evaluation of Psychophysical Fitness in Drivers over 65 Years of Age

BACKGROUND

The deterioration of cognitive and psychophysical ability associated with aging has an effect on road safety, especially in the driving of vehicles. The current study's main objective is to evaluate the psychophysical aptitudes in drivers over 65 years of age in a sample of drivers in Spain.

METHODS

The sample was formed of a total of 1663 drivers who attended a Driver Recognition Center. The evaluation of their psychophysical aptitudes was carried out following the Medical-Psychological Exploration Protocol for Driver Recognition Centers, edited by the Ministry of Health and the General Directorate of Traffic.

RESULTS

The results show increased restrictions in the evaluation of driving ability with age, which are especially significant after 75 years of age. Regarding sex, 70.1% of women have an approved evaluation, compared to men aged between 65-69, although from 69 onwards, the percentage of approved women decreases significantly. The loss of visual capabilities and poor performance in psycho-technical tests are the main causes associated with an evaluation with restrictions, with the number of restrictive conditions increasing with age.

CONCLUSIONS

There is an increase in the number of cases with age-related restrictions, especially in the case of women and ophthalmologic-related problems, although the majority of drivers over 65 years old continue driving, thus continuing with a practice that has been related to the well-being and quality of life of older adults.

Age-related changes in midfrontal theta activity during steering control: A driving simulator study

Motor control, a ubiquitous part of driving, requires increased cognitive controlled processing in older adults relative to younger adults. However, the influence of aging on motor-related neural mechanisms in the context of driving has rarely been studied. The present study aimed to identify age-related changes in cognitive control and attention allocation during a simulated steering task, using electroencephalography. Midfrontal theta, a marker for cognitive control, and posterior alpha power, a marker for attention allocation, were measured in a total of 26 young, 25 middle-aged, and 28 older adults. By adapting driving speed, the difficulty level of this steering task was individualized for each participant. Results show age-related changes in midfrontal theta power, but not in posterior alpha power, despite similar steering accuracy across age groups. Specifically, only younger and, to a lesser extent, middle-aged adults exhibited increased theta power while driving through more demanding curved segments relative to straight segments. In contrast, theta power upregulation was absent in older adults, suggesting a saturation of cognitive resources while driving, possibly due to a limitation in resource capacity, or less automatic motor-related neural processing.

A comparative assessment of subjective experience in simulator and on-road driving under normal and time pressure driving conditions

This study conducts a comparative assessment of subjective experience of real-world and simulated world driving for investigating factors leading to simulator sickness. Thirty professional car drivers drove a fixed-base driving simulator in real and simulated worlds under No Time Pressure (NTP) and Time Pressure (TP) driving conditions. Drivers rated their perceptions based on real-world driving and simulator driving experiences after each driving session with respect to three factors: simulator sickness, mental workload, and sense of presence. The structural equation model results revealed that drivers experienced high mental workload due to TP driving conditions (factor loading = 0.90) and repeated exposure to simulated world (factor loading = 0.20) which induced simulator sickness (factor loading = 0.41) and resulted in low sense of presence (factor loading = -0.18). Thus, it can be concluded that lack of experience with virtual reality induced high simulator sickness, increased mental workload, and low sense of presence.

Distraction "Hangover": Characterization of the Delayed Return to Baseline Driving Risk After Distracting Behaviors

OBJECTIVE

We measured how long distraction by a smartphone affects simulated driving behaviors after the tasks are completed (i.e., the distraction hangover).

BACKGROUND

Most drivers know that smartphones distract. Trying to limit distraction, drivers can use hands-free devices, where they only briefly glance at the smartphone. However, the cognitive cost of switching tasks from driving to communicating and back to driving adds an underappreciated, potentially long period to the total distraction time.

METHOD

Ninety-seven 21- to 78-year-old individuals who self-identified as active drivers and smartphone users engaged in a simulated driving scenario that included smartphone distractions. Peripheral-cue and car-following tasks were used to assess driving behavior, along with synchronized eye tracking.

RESULTS

The participants' lateral speed was larger than baseline for 15 s after the end of a voice distraction and for up to 25 s after a text distraction. Correct identification of peripheral cues dropped about 5% per decade of age, and participants from the 71+ age group missed seeing about 50% of peripheral cues within 4 s of the distraction. During distraction, coherence with the lead car in a following task dropped from 0.54 to 0.045, and seven participants rear-ended the lead car. Breadth of scanning contracted by 50% after distraction.

CONCLUSION

Simulated driving performance drops dramatically after smartphone distraction for all ages and for both voice and texting.

APPLICATION

Public education should include the dangers of any smartphone use during driving, including hands-free.

Factors Associated with Fatigued Driving among Australian Truck Drivers: A Cross-Sectional Study

BACKGROUND

Fatigued driving is one of the leading factors contributing to road crashes in the trucking industry. The nature of trucking, prolonged working time, and irregular sleep patterns can negatively impact drivers' health and wellbeing. However, there is limited research in Australia investigating the impact of demographic, occupational, or lifestyle factors on fatigue among truck drivers.

OBJECTIVE

This cross-sectional study examines the role of demographic, occupational, lifestyle, and other health risk factors associated with fatigue among Australian truck drivers.

METHOD

This study was part of a larger study that used a short online survey with a follow-up telephone survey to capture in-depth information on a wide range of determinants related to truck drivers' physical and mental health outcomes. Fatigue was measured by three questions, including the frequency of fatigue, fatigue management training, and strategies used to combat fatigue. Multivariate regression analysis was used to determine the specific impact of demographics, occupational factors, lifestyle factors, and other health risk factors on fatigue.

RESULTS

In total, 332 drivers completed both the online and telephone surveys; 97% were male, representing drivers from broad age groups and professional experience. The odds of being in the high-risk fatigue group were nearly three times higher in drivers who worked 40-60 h compared to those who worked < 40 h. Poor sleep increased the odds of high-risk fatigue by seventimes (95% CI: 2.26-21.67, p = 0.001). Drivers who reported experiencing loneliness also had double the odds of being at high risk of fatigued driving.

CONCLUSIONS

The increased risk of fatigue in truck drivers is associated with prolonged working hours, poor sleep, and social aspects such as loneliness. Further interventions seeking to reduce driver fatigue should consider the impact of work schedules, the availability of quality sleeping spaces, and the level of social connections.

Simulator assessment of innovative intersection designs on driver speeds and trajectories

Intersections are over-represented in crash statistics internationally, suggesting that treatments targeting intersections could substantially improve road safety. Aligning with a Safe Systems approach, several innovative intersection configurations have been proposed. We evaluated the effectiveness of five designs on reducing speed and modifying conflict angles using a driving simulator. The designs were 1) cut-through, 2) modified restricted squircle, 3) unrestricted squircle, 4) raised approach, and 5) raised intersection. For the higher speed green light condition, speed reductions for vehicles travelling straight through the intersection were seen for all five innovative designs on approach to the intersection and at critical conflict points within the intersection. Within the intersection specifically, speed reductions ranged from 1) 7-8 km/h for the modified restricted squircle, 2) 12.5-16.5 km/h for the unrestricted squircle, raised approach, and raised intersection, and 3) 15-19 km/h for the cut-through. In contrast, speeds for drivers turning right were either not substantially reduced (modified restricted squircle, unrestricted squircle, and raised intersection) or were increased (raised approach and cut-through). Beneficial modification of conflict angles were also observed at conflict points for three of the five designs: cut-through, and two variations of the squircle design. Innovative intersection designs may be effective in reducing intersection crash risk by reducing speeds and conflict angles.

Driving, Social Distancing, Protective, and Coping Behaviors of Older Adults Before and During COVID-19

A thorough understanding of individual characteristics of older adults during the COVID-19 pandemic is critical for managing the ongoing pandemic course and planning for the future pandemics. Here, we explore the impact of the COVID-19 pandemic on driving, social distancing, protective, and coping behaviors of older adults. This study reports data on participants aged above 65 whose driving behaviors are being monitored using Global Positioning System (GPS) devices. Participants completed a COVID-19 survey in May 2020. We found that older adults decreased their number of days driving, number of trips per day, as well as average driving speed, and had fewer speeding incidents following COVID-19 onset. We also show that female and African American older adults engaged in more positive coping and cleaning behaviors, and had greater decreases in the number of days driving during the pandemic. The findings highlight the importance of considering older adults' individual characteristics for an equitable response to the COVID-19 pandemic.

Modeling the Car-Following Behavior with Consideration of Driver, Vehicle, and Environment Factors: A Historical Review

Car-following behavior is the result of the interaction of various elements in the specific driver-vehicle-environment aggregation. Under the intelligent and connected condition, the information perception ability of vehicles has been significantly enhanced, and abundant information about the driver-vehicle-environment factors can be obtained and utilized to study car-following behavior. Therefore, it is necessary to comprehensively take into account the driver-vehicle-environment factors when modeling car-following behavior under intelligent and connected conditions. While there are a considerable number of achievements in research on car-following behavior, a car-following model with comprehensive consideration of driver-vehicle-environment factors is still absent. To address this gap, the literature with a focus on car-following behavior research with consideration of the driver, vehicle, or environment were reviewed, the contributions and limitations of the previous studies were analyzed, and the future exploration needs and prospects were discussed in this paper. The results can help understand car-following behavior and the traffic flow characteristics affected by various factors and provide a reference for the development of traffic flow theory towards smart transportation systems and intelligent and connected driving.

Lifestyle Matters: Effects of Habitual Physical Activity on Driving Skills in Older Age

Research on multitasking driving has suggested age-related deterioration in driving performance. It has been shown that physical and cognitive functioning, which are related to driving performance and decline with aging, are positively associated with physical activity behavior. This study aimed to explore whether driving performance decline becomes severe with advancing age and whether physical activity behavior modifies age-related deterioration in driving performance. A total of one hundred forty-one healthy adults were categorized into three groups based on their age; old-old (74.21 ± 2.33 years), young-old (66.53 ± 1.50 years), and young adults (23.25 ± 2.82 years). Participants completed a realistic multitasking driving task. Physical activity and cardiorespiratory fitness levels were evaluated. Older groups drove more slowly and laterally than young adults, and old-old adults drove slower than young-old ones across the whole driving course. Physical activity level did not interact with the aging effect on driving performance, whereas cardiovascular fitness interacted. Higher-fitness young-old and young adults drove faster than higher-fitness old-old adults. Higher-fitness old adults drove more laterally than higher-fitness young adults. The present study demonstrated a gradual decline in driving performance in old adults, and cardiorespiratory fitness interacted with the aging effect on driving performance. Future research on the interaction of aging and physical activity behavior on driving performance in different age groups is of great value and may help deepen our knowledge.

Cannabis Legalization and Detection of Tetrahydrocannabinol in Injured Drivers

BACKGROUND

The effect of cannabis legalization in Canada (in October 2018) on the prevalence of injured drivers testing positive for tetrahydrocannabinol (THC) is unclear.

METHODS

We studied drivers treated after a motor vehicle collision in four British Columbia trauma centers, with data from January 2013 through March 2020. We included moderately injured drivers (those whose condition warranted blood tests as part of clinical assessment) for whom excess blood remained after clinical testing was complete. Blood was analyzed at the provincial toxicology center. The primary outcomes were a THC level greater than 0, a THC level of at least 2 ng per milliliter (Canadian legal limit), and a THC level of at least 5 ng per milliliter. The secondary outcomes were a THC level of at least 2.5 ng per milliliter plus a blood alcohol level of at least 0.05%; a blood alcohol level greater than 0; and a blood alcohol level of at least 0.08%. We calculated the prevalence of all outcomes before and after legalization. We obtained adjusted prevalence ratios using log-binomial regression to model the association between substance prevalence and legalization after adjustment for relevant covariates.

RESULTS

During the study period, 4339 drivers (3550 before legalization and 789 after legalization) met the inclusion criteria. Before legalization, a THC level greater than 0 was detected in 9.2% of drivers, a THC level of at least 2 ng per milliliter in 3.8%, and a THC level of at least 5 ng per milliliter in 1.1%. After legalization, the values were 17.9%, 8.6%, and 3.5%, respectively. After legalization, there was an increased prevalence of drivers with a THC level greater than 0 (adjusted prevalence ratio, 1.33; 95% confidence interval [CI], 1.05 to 1.68), a THC level of at least 2 ng per milliliter (adjusted prevalence ratio, 2.29; 95% CI, 1.52 to 3.45), and a THC level of at least 5 ng per milliliter (adjusted prevalence ratio, 2.05; 95% CI, 1.00 to 4.18). The largest increases in a THC level of at least 2 ng per milliliter were among drivers 50 years of age or older (adjusted prevalence ratio, 5.18; 95% CI, 2.49 to 10.78) and among male drivers (adjusted prevalence ratio, 2.44; 95% CI, 1.60 to 3.74). There were no significant changes in the prevalence of drivers testing positive for alcohol.

CONCLUSIONS

After cannabis legalization, the prevalence of moderately injured drivers with a THC level of at least 2 ng per milliliter in participating British Columbia trauma centers more than doubled. The increase was largest among older drivers and male drivers. (Funded by the Canadian Institutes of Health Research.).

Impact of Age on Takeover Behavior in Automated Driving in Complex Traffic Situations: A Case Study of Beijing, China

Research on the influence of age on various automated driving conditions will contribute to an understanding of driving behavior characteristics and the development of specific automated driving systems. This study aims to analyze the relationship between age and takeover behavior in automated driving, where 16 test conditions were taken into consideration, including two driving tasks, two warning times and four driving scenarios. Forty-two drivers in Beijing, China in 2020 were recruited to participate in a static driving simulator with Level 3 (L3) conditional automation to obtain detailed test information of the recorded takeover time, mean speed and mean lateral offset. An ANOVA test was proposed to examine the significance among different age groups and conditions. The results confirmed that reaction time increased significantly with age and the driving stability of the older group was worse than the young and middle groups. It was also indicated that the older group could not adapt to complex tasks well when driving due to their limited cognitive driving ability. Additionally, the higher urgency of a scenario explained the variance in the takeover quality. According to the obtained influencing mechanisms, policy implications for the development of vehicle automation, considering the various driving behaviors of drivers, were put forward, so as to correctly identify the high-risk driving conditions in different age groups. For further research, on-road validation will be necessary in order to check for driving simulation-related effects.

Do Impulse Control Disorders Impair Car Driving Performance in Patients with Parkinson's Disease?

BACKGROUND

Based on data regarding the prevalence of Parkinson's disease (PD), the prevalence of impulsive control disorders (ICD) in PD, and the percentage of PD patients driving a car, it has to be assumed that at least 50,000 PD patients with ICD in Germany actively drive a car. However, these patients might be at risk for unsafe driving due to ICD-related dysfunctions such as failure to resist an impulse or temptation, to control an act or other altered neurobehavioral processes.

OBJECTIVE

This study determines the influence of ICD on driving ability in PD.

METHODS

We prospectively compared driving simulator performance of 23 PD patients with and 23 matched patients without ICD. ICD had to be socially compensated and presence was defined clinically for primary and questionnaire-based (QUIP-RS) for post-hoc analyses. Furthermore, between-group comparisons of driving-relevant neuropsychological tests were executed.

RESULTS

Except from a lower blinking frequency when changing lanes, overall driving safety of patients with ICD did not differ significantly from those without-regardless of the clinical or QUIP-RS-based ICD definition. ICD severity did not correlate with driving performance, but the latter correlated significantly with mean reaction times and certain neuropsychiatric tests (MoCA, TMT-A, TAP-M "flexibility" and DBQ "error").

CONCLUSION

Clinically compensated ICD does not seem to impair driving safety in PD patients. Rather, cognitive and attentional deficits appear to be clinical markers for driving uncertainty.

A Longitudinal Study Examining Self-Regulation Practices in Older Drivers with and without Suspected Mild Cognitive Impairment

Purpose

Mild cognitive impairment can impact driving performance and self-regulation practices. However, there is little evidence on how cognitive impairment may impact these self-regulation practices over a period of time. Therefore, the aim of this study was to examine changes in the number and type of situations in which older drivers with and without suspected mild cognitive impairment (MCI) self-regulate their driving over a one-year period, after accounting for relevant confounders.

Participants and Methods

A longitudinal cohort study involving older drivers (65+ years) from metropolitan Western Australia was interviewed by a telephone interview at baseline and one-year follow-up. The Telephone Cognitive Screen (T-CogS) was also administered to determine changes in their cognitive status. The outcome of interest was the number and type of situations older drivers self-regulated their driving.

Results

A total of 670 drivers were interviewed at baseline (suspected MCI: n = 227; no cognitive impairment: n = 443) and one-year follow-up (suspected MCI: n = 251; no cognitive impairment: n = 419), which provided 1340 observations. Drivers with suspected MCI increased the number of driving situations in which they self-regulated by 13% over a period of one-year compared with drivers without cognitive impairment (IRR = 1.13, 95% CI = 1.02–1.27, p = 0.025). Specifically, drivers with suspected MCI had 60% increased odds of self-regulating when “making turns across oncoming traffic” compared with drivers without cognitive impairment (unadjusted OR = 1.60, 95% CI = 1.02–2.53, p = 0.041). Other significant factors included being female (IRR = 1.87, 95% = 1.52–2.32, p = 0.001), aged 75+ years (IRR = 1.33, 95% CI = 1.10–1.60, p = 0.003), higher number of comorbidities (1–3 comorbidities: IRR = 1.26, 95% CI = 1.01–1.58, p = 0.040; 4+ comorbidities: IRR = 1.39, 95% CI = 1.08–1.78, p = 0.011), “decreased driving confidence” (IRR = 1.32, 95% CI = 1.10–1.58, p-value = 0.003) and “preference of having someone else drive” (IRR = 1.38, 95% CI = 1.12–1.70, p = 0.003). Having one or more traffic infringements was also associated with a decrease in the number of self-regulated driving situations (IRR = 0.80, 95% CI = 0.67–0.95, p = 0.011).

Conclusion

Over a one-year period, drivers with suspected MCI increased the number of situations in which they self-regulated their driving compared with drivers without cognitive impairment, particularly when “making turns across oncoming traffic”. Future studies should examine whether this increase in the types and number of self-regulated driving situations is enough to compensate for declines in cognition.

Traffic Injury Risk Based on Mobility Patterns by Gender, Age, Mode of Transport and Type of Road

The role of gender and age in the risk of Road Traffic Injury (RTI) has not been fully explored and there are still significant gaps with regard to how environmental factors, such as road type, affect this relationship, including mobility as a measure of exposure. The aim of this research is to investigate the influence of the environmental factor road type taking into account different mobility patterns. For this purpose, a cross-sectional study was carried out combining two large databases on mobility and traffic accidents in Andalusia (Spain). The risk of RTI and their severity were estimated by gender and age, transport mode and road type, including travel time as a measure of exposure. Significant differences were found according to road type. The analysis of the rate ratio (Ratemen/Ratewomen), regardless of age, shows that men always have a higher risk of serious and fatal injuries in all modes of transport and road types. Analysis of victim rates by gender and age groups allows us to identify the most vulnerable groups. The results highlight the need to include not only gender and age but also road type as a significant environmental factor in RTI risk analysis for the development of effective mobility and road safety strategies.

Organizational and personal factors in occupational traffic injuries at work in Spain

OBJECTIVE

Traffic crashes are one of the major causes of deaths at work. However, most of the literature on traffic crashes did not study the influence of worker and organization conditions. The current paper analyses the influence of the personal and organizational factors associated with the severity of occupational traffic crashes.

METHODS

A total of 724,596 occupational traffic crashes that occurred in Spain from 2009 to 2019 were analyzed. Men suffered 59% of crashes registered, while workers younger than 30 represented 31.3% of crashes studied. Variables included in the Official Occupational Accident Report were analyzed using logistic regression calculating odds ratios.

RESULTS

Results showed that a foreign, professional male driver from a small company who is older than 55 years was more likely to suffer a fatal crash. In contrast, a Spanish, nonprofessional female driver from a medium or big company who is younger than 30 years is more likely to suffer light consequences.

CONCLUSIONS

Findings from the current research could help to improve the safety training programmes in companies considering their personal and business variables such as age, gender, or company staff, especially in small companies. Future research should collect and analyze additional variables combining different data sources.

The Impact of Cognition and Gender on Speeding Behaviour in Older Drivers with and without Suspected Mild Cognitive Impairment

Purpose

Mild cognitive impairment and gender can impact different aspects of driving performance and behaviour in older drivers. However, there is little evidence on how these may affect naturalistic speeding behaviour. Therefore, the aim of this study was to examine the relationship between speeding events and cognitive status for older male and female drivers.

Participants and Methods

A naturalistic driving study collected objective driving information over a two-week period using an in-vehicle monitoring device from 36 older drivers with suspected mild cognitive impairment and 35 older drivers without cognitive impairment. The outcome of interest examined was the number of speeding events, defined as travelling 5+ km/h over the posted speed limit for at least a minute.

Results

The majority of participants (n=58, 81.69%) did not have a speeding event during the two-week monitoring period. Twenty-three speeding events were recorded among seven drivers with suspected mild cognitive impairment and six drivers without cognitive impairment. The majority of speeding events (82.61%) were by older male drivers and occurred in 60km/h and 70km/h speed zones. The results of the two negative binomial regression models found that in older male drivers, suspected mild cognitive impairment (IRR=7.45, 95% CI=1.53–36.15, p=0.01) was associated with a significantly higher rate of speeding events, while increasing age was associated with a lower rate of speeding events (IRR=0.80, 95% CI=0.64–1.00, p=0.04). For older female drivers, there were no factors significantly associated with the rate of speeding events.

Conclusion

While the overall number of speeding events were infrequent, suspected mild cognitive impairment was associated with a significant increase in the rate of speeding events for older male drivers, but not for older female drivers. Speeding interventions and injury prevention policy strategies may need to be targeted differently for male and female drivers with mild cognitive impairment.

Development of an Android-Based Self-Report Assessment for Elderly Driving Risk (SAFE-DR) App: Mixed Methods Study

Background

Self-report assessments for elderly drivers are used in various countries for accessible, widespread self-monitoring of driving ability in the elderly population. Likewise, in South Korea, a paper-based Self-Report Assessment for Elderly Driving Risk (SAFE-DR) has been developed. Here, we implemented the SAFE-DR through an Android app, which provides the advantages of accessibility, convenience, and provision of diverse information, and verified its reliability and validity.

Objective

This study tested the validity and reliability of a mobile app-based version of a self-report assessment for elderly persons contextualized to the South Korean culture and compared it with a paper-based test.

Methods

In this mixed methods study, we recruited and interviewed 567 elderly drivers (aged 65 years and older) between August 2018 and May 2019. For participants who provided consent, the app-based test was repeated after 2 weeks and an additional paper-based test (Driver 65 Plus test) was administered. Using the collected data, we analyzed the reliability and validity of the app-based SAFE-DR. The internal consistency of provisional items in each subdomain of the SAFE-DR and the test-retest stability were analyzed to examine reliability. Exploratory factor analysis was performed to examine the validity of the subdomain configuration. To verify the appropriateness of using an app-based test for older drivers possibly unfamiliar with mobile technology, the correlation between the results of the SAFE-DR app and the paper-based offline test was also analyzed.

Results

In the reliability analysis, Cronbach α for all items was 0.975 and the correlation of each item with the overall score ranged from r=0.520 to r=0.823; 4 items with low correlations were removed from each of the subdomains. In the retest after 2 weeks, the mean correlation coefficient across all items was r=0.951, showing very high reliability. Exploratory factor analysis on 40 of the 44 items established 5 subdomains: on-road (8 items), coping (16 items), cognitive functions (5 items), general conditions (8 items), and medical health (3 items). A very strong negative correlation of –0.864 was observed between the total score for the app-based SAFE-DR and the paper-based Driver 65 Plus with decorrelation scales. The app-based test was found to be reliable.

Conclusions

In this study, we developed an app-based self-report assessment tool for elderly drivers and tested its reliability and validity. This app can help elderly individuals easily assess their own driving skills. Therefore, this assessment can be used to educate drivers and for preventive screening for elderly drivers who want to renew their driver’s licenses in South Korea. In addition, the app can contribute to safe driving among elderly drivers.

Review of Studies on Older Drivers' Behavior and Stress-Methods, Results, and Outlook

This paper presents a review on relevant studies and reports related to older drivers’ behavior and stress. Questionnaires, simulators, and on-road/in-vehicle systems are used to collect driving data in most studies. In addition, research either directly compares older drivers and the other drivers or considers participants according to various age groups. Nevertheless, the definition of ‘older driver’ varies not only across studies but also across different government reports. Although questionnaire surveys are widely used to affordably obtain massive data in a short time, they lack objectivity. In contrast, biomedical information can increase the reliability of a driving stress assessment when collected in environments such as driving simulators and on-road experiments. Various studies determined that driving behavior and stress remain stable regardless of age, whereas others reported degradation of driving abilities and increased driving stress among older drivers. Instead of age, many researchers recommended considering other influencing factors, such as gender, living area, and driving experience. To mitigate bias in findings, this literature review suggests a hybrid method by applying surveys and collecting on-road/in-vehicle data.

Reaction time and brake pedal force after total knee replacement: timeframe for return to car driving

PURPOSE

This prospective cohort study aimed to examine objective and subjective parameters in patients who underwent total knee replacement (TKR) to assess from when on driving a car can be deemed safe again.

METHODS

Thirty patients (16 women, 14 men, age 66 ± 11 years) who received TKR of the right knee and 45 healthy controls (26 women, 19 men, age 32 ± 9 years) were asked to perform an emergency braking manoeuvre using a driving simulator. Brake pedal force (BPF), neuronal reaction time (NRT), brake reaction time (BRT), and subjective parameters (pain, subjective driving ability) were measured preoperatively as well as 5 days, 3-4, and 6 weeks after TKR.

RESULTS

Preoperative NRT was 506 ± 162 ms, BRT 985 ± 356 ms, and BPF 614 ± 292 N. NRT increased to 561 ± 218 ms, BRT to 1091 ± 404 ms and BPF decreased to 411 ± 191 N 5 days after TKR. Three weeks after surgery, NRT was 581 ± 164 ms and BRT 1013 ± 260 ms, while BPF increased to 555 ± 200 N. Only BPF showed significant differences (p < 0.01). In week 6, all parameters were restored to baseline levels; patients showed significant pain decrease and evaluated their driving ability as "good" again.

CONCLUSION

BPF was the only parameter displaying a significant postoperative decrease. However, preoperative patients' baseline levels and subjective confidence in driving ability were only reached 6 weeks after the operation. These results indicate that a minimum waiting period of 6 weeks should be considered before patients can safely participate in road traffic at their individual preoperative safety level again.

LEVEL OF EVIDENCE

II.

The Effects of Acute Exercise on Driving and Executive Functions in Healthy Older Adults

The benefits of exercise on cognitive functioning in older adults are well recognized. One limitation of the current literature is that researchers have almost exclusively relied on well-controlled laboratory tasks to assess cognition. Moreover, the effects of a single bout of aerobic exercise in older adults have received limited attention. The proposed study addresses these limitations by assessing the effects of a single bout of exercise on a more ecologically valid task - driving. Seventy-one participants (M _age = 66.39 ± 4.70 years) were randomly allocated to 20min cycling at moderate intensity or sitting and watching driving videos. Participants were then tested on their driving performance using a driving simulator. Driving performance was measured with three different scenarios assessing decision making, driving errors, reaction time, and attention. On a subsequent session, all participants were tested on executive functioning before and after a fitness test. Non-significant effects of exercise were observed on driving performance. However, participants performed better on the Trail Making Test (Cohen's d = 0.25) and Stroop test (d = 0.50) after the fitness test compared to their baseline. These results suggest that post-exercise cognitive improvements do not transfer to improved driving performance among healthy older adults. This study also highlights the importance of assessing expectations as a possible moderator of the effects of acute exercise on activities of daily living. Future studies must examine other relevant ecologically valid tasks and ensure similar expectations between experimental and control groups to further advance the knowledge base in the field.

When virtuality becomes real: Relevance of mental abilities and age in simulator adaptation and dropouts

Previous studies increasingly report problems with simulator adaptation as well as dropouts. Therefore, the present study aims at better understanding these aspects by considering individual factors, such as age and mental abilities. 414 people were tested with commonly used neuropsychological measures as well as within a driving simulator which consists of a close-to-production vehicle of the compact class. In contrast to previous findings, neither a significant relationship between age and the time of adaptation nor an interaction between age and mental abilities on adaptation time could be identified. However, the time participants spent in the simulator (simulator dropout) significantly correlated with age but not with mental abilities. People who showed no adaptation spent significantly less time in the simulator, because of the occurrence of simulator sickness. Although attention was only mildly associated with the time of simulator adaptation, further research on this linkage is suggested. Practitioner summary: The study at hand clarifies the relevance of considering the process of simulator adaptation within simulator studies. However, the present findings suggest no relation between age and the time of adaptation but with simulator dropouts. Abbreviations: TMT: trail making test; LPS: leistungsprüfsystem; IOP: index of performance; ALFASY: altersgerechte fahrerassistenzsystem (Age-based Driver Assistance Systems).

Predictors of accidents in people with mild cognitive impairment, mild dementia due to Alzheimer's disease and healthy controls in simulated driving

OBJECTIVES

To examine the driving variables that predict accident probability in mild dementia due to Alzheimer's disease (AD), mild cognitive impairment (MCI) and healthy older control drivers in simulated driving. To compare the three groups in mean performance and in frequency of scores exceeding 1.5 SD from the mean.

METHODS/DESIGN

Participants were 37 drivers with MCI, 16 drivers with AD, and 21 control drivers over the age of 52. Driving measures were derived from four rural driving conditions: moderate traffic without and with distraction and high traffic without and with distraction. The measures were z-transformed based on the performance of 90 control drivers of different ages. Two unexpected incidents occurred per condition, requiring the sudden breaking to avoid an accident.

RESULTS

Drivers with AD showed significantly lower average speed, speed variability, greater headway distance, headway variability and average reaction time (RT) than control drivers. Drivers with MCI showed significantly lower average speed, greater headway distance and average RT than control drivers in the two conditions of distraction. No differences were found in accident probability. Drivers with AD had more deviant scores than both control drivers and drivers with MCI in most comparisons. Predictors of accident probability were average RT, speed variability and lateral position variability but MCI and AD status were not significant predictors in any of the regression models.

CONCLUSIONS

Despite significant differences in performance, drivers with MCI and AD did not differ in accident probability from control drivers. An individualized approach of examining individual driving performance is recommended.

Brake time is correlated with lower extremity strength, dynamic balance and low-contrast sensitivity in unpredictable driving situations in elderly drivers compared with young drivers: A cross-sectional study

AIMS

To compare physical function, driving fitness and brake time of young and elderly drivers, and to identify the association of physical function and driving fitness with brake time in elderly drivers in predictable or unpredictable situations during driving.

METHODS

This study included 86 participants (50 men and 36 women), comprising 52 elderly drivers (age: 72.44 years, weight: 60.39 kg, height: 158.06 cm) and 34 young drivers (age: 26.53 years, weight: 63.74 kg, height: 153.65 cm), with a valid driver's license who drive at least once a week. Physical function was measured as upper and lower body flexibility and strength, dynamic balance and aerobic endurance. Driving fitness was measured as high- and low-contrast sensitivity, route planning, visualization of missing information, visual search with divided attention and visual information processing speed using the DrivingHealth® Inventory. Brake time and braking distance was evaluated as unpredictable and predictable driving situations.

RESULTS

Measurements of all categories, except lower extremity flexibility, endurance and high-contrast sensitivity, were significantly lower in elderly drivers than in young drivers. Brake time did not differ in predictable situations but was slower (P = 0.004) in elderly drivers in unpredictable situations. In elderly drivers, upper body strength (P = 0.036), dynamic balance (P < 0.001) and low-contrast sensitivity (P = 0.003) were associated with brake time in unpredictable driving situations.

CONCLUSIONS

In unpredictable situations, slower brake time in elderly drivers is associated with lower limb muscle strength, agility and low-contrast sensitivity. Therefore, for safe driving, these parameters should be considered as guidelines for maintaining the driving ability of elderly drivers and aging people. Geriatr Gerontol Int 2020; ••: ••-••.

Effects of aging on foot pedal responses to visual stimuli

BACKGROUND

Car accidents due to unexpected forward or backward runaway by older drivers are a serious social problem. Although the cause of these accidents is often attributed to stepping on the accelerator instead of the brake, it is difficult to induce such pedal application errors systematically with usual drive simulators. We developed a simple personal computer system that induces the pedal errors, and investigate the effects of age on the error behaviors.

METHODS

The system consisted of a laptop computer and a three-pedal foot mouse. It measured response time, accuracy, and flexibility of pedal operation to visual stimuli. The system displayed two open circles on the computer display, lighting one of the circles in a random order and interval. Subjects were instructed to press the foot pedal with their right foot as quickly as possible when the circle was lit; the ipsilateral pedal to the lit circle in a parallel mode and the contralateral pedal in a cross mode. When the correct pedal was pressed, the light went off immediately, but when the wrong pedal was pressed, the buzzer sounded and the light remained on until the correct pedal was pressed. During a 6-min trial, the mode was switched between parallel and cross every 2 min. During the cross mode, a cross mark appears on the display. The pedal responses were evaluated in 52 subjects divided into young (20-29 years), middle-aged (30-64 years), and older (65-84 years) groups. Additionally, the repeatability of the pedal response characteristic indicators was examined in 14 subjects who performed this test twice.

RESULTS

The mean response time was 95 ms (17%) longer in the older group than in the young group. More characteristically, however, the older group showed 2.1 times more frequent pedal errors, fell into long hesitations (response freezing > 3 s) 16 times more often, and took 1.8 times longer period to correct the wrong pedal than the young groups. The indicators of pedal response characteristics showed within-individual repeatability to the extent that can identify the age-dependent changes.

CONCLUSIONS

Hesitations and extended error correction time can be associated with increased crash risk due to unexpected runaway by older drivers. The system we have developed may help to uncover and evaluate physiological characteristics related to crash risk in the elderly population.

Safe mobility, socioeconomic inequalities, and aging: A 12-year multilevel interrupted time-series analysis of road traffic death rates in a Latin American country

As the resources for road safety in developing countries are scarce and unevenly distributed, vulnerable road users -such as the elderly- may be particularly at risk of road traffic deaths. To date, the impact of road safety measures over the rate of road traffic deaths in older adults (60 years or older), considering the within-country socioeconomic inequalities, has not been explored in developing nations. This study takes the Chilean case as an example -with its 2005 traffic law reform as one of the road safety measures investigated-, in which open data available from official national sources for all its 13 regions over the 2002-2013 period were used for a multilevel interrupted time-series analysis. A statistically significant secular reduction of the rates of road traffic deaths in the elderly population was found (incidence rate ratio [IRR] 0.95, 95% confidence interval [CI] 0.91 to 0.99), but no evidence for a significant intercept or slope change after the traffic law reform was observed. Regions with the highest number of traffic offenses prosecuted in local police courts had lower rates of road traffic deaths in older adults (IRR 0.95, 95% CI 0.90 to 1.00), and those regions in the third (IRR 1.61, 95% CI 1.16 to 2.25) and the fifth (IRR 1.66, 95% CI 1.08 to 2.54) quintiles of socioeconomic deprivation had higher rates of road traffic deaths in the elderly. Such findings strongly support the conceptualization of the road safety of seniors in developing countries as a social equity issue, with implications for the design of traffic regulations and road environments.

Alzheimer Disease Biomarkers and Driving in Clinically Normal Older Adults: Role of Spatial Navigation Abilities

PURPOSE

Older adults experience impaired driving performance, and modify their driving habits, including limiting amount and spatial extent of travel. Alzheimer disease (AD)-related pathology, as well as spatial navigation difficulties, may influence driving performance and driving behaviors in clinically normal older adults. We examined whether AD biomarkers [cerebrospinal fluid (CSF) concentrations of Aβ42, tau, and ptau181] were associated with lower self-reported spatial navigation abilities, and whether navigation abilities mediated the relationship of AD biomarkers with driving performance and extent.

METHODS

Clinically normal older adults (n=112; aged 65+) completed an on-road driving test, the Santa Barbara Sense of Direction scale (self-report measure of spatial navigation ability), and the Driving Habits Questionnaire for an estimate of driving extent (composite of driving exposure and driving space). All participants had a lumbar puncture to obtain CSF.

RESULTS

CSF Aβ42, but not tau or ptau181, was associated with self-reported navigation ability. Lower self-reported navigation was associated with reduced driving extent, but not driving errors. Self-reported navigation mediated the relationship between CSF Aβ42 and driving extent.

CONCLUSIONS

Findings suggest that cerebral amyloid deposition is associated with lower perceived ability to navigate the environment, which may lead older adults with AD pathology to limit their driving extent.

Aging Affects the Ability to Process the Optic Flow Stimulations: A Functional Near-Infrared Spectrometry Study

Optic flow (OF) has been utilized to investigate the sensory integration of visual stimuli during postural control. It is little known how the OF speed affects the aging brain during the sensory integration process of postural control. This study was to examine the effect of OF speeds on the brain activation using functional near-infrared spectroscopy (fNIRS) and postural sway between younger and older adults. Eleven healthy younger adults (5M/6F, age 22 ± 1-year-old) and ten healthy older adults (4M/6F, age 71 ± 5-year-old) participated in this study. A virtual reality headset was used to provide the OF stimulus at different speeds. A forceplate was used to record the center-of-pressure to compute the amplitude of postural sway (peak-to-peak). Compared with younger adults, older adults showed significantly increased activation in the OF speed of 10 m/s and decreased activation in the OF speed of 20 m/s in the left dorsolateral prefrontal cortex. Older adults also showed decreased activation in the left temporoparietal region (VEST) in the OF speed of 20 m/s. A significant difference in peak-to-peak was found between groups. Our results indicated that age might be associated with the ability to process fast OF stimulation.

Incidence of fatalities of road traffic accidents associated with alcohol consumption and the use of psychoactive drugs: A 7-year survey (2011-2017)

Driving under the influence of alcohol and/or psychoactive substances increases the risk of severe, even fatal motor vehicle accidents. The aim of this descriptive study was to present the impact of alcohol and/or psychoactive substances on fatal road traffic accidents (RTAs) during the period 2011-2017. For this purpose, the toxicological investigation reports from the Department of Forensic Medicine and Toxicology of the University of Athens were used. In total, 1,841 (32.2%) of the autopsies conducted by the Department of Forensic Medicine and Toxicology of the National and Kapodistrian University of Athens over a 7-year period (2011-2017) were victims of fatal RTAs. Blood and urine samples were collected and analyzed for the presence of alcohol and psychoactive substances. The results were classified according to sex, age, victim (car driver, motorcyclist, pedestrian, or passenger) and the date the accident occurred (day, month and year). In total, 40.7% of the RTA-related fatalities were associated with alcohol consumption, among which 20.3% were car drivers. Of these, 87.3% were male victims. A higher frequency of RTA-related fatalities associated with a blood alcohol concentration (BAC) >110 mg/dl was encountered in younger compared with older age groups. Psychoactive substances were detected in 348 (18.9%) of the victims (cannabis in 46.6% of these, benzodiazepines in 25.9%, opiates in 16.4% and cocaine in 11.1% of these). The percentage of the RTA-related victims that had consumed alcohol in combination with other psychoactive substances was 4.5%. On the whole, the findings of this study suggest that alcohol and psychoactive substances are probably risk factors for RTA-related fatalities.

Violent deaths among elderly in Attica, Greece: A 5-year survey (2011-2015)

According to World Health Organization (WHO) estimations, approximately 6 million people lose their lives yearly due to some kind of injury, while one-third of these incidents are due to violent acts. Violent deaths include accidents (road traffic accidents, drownings, falls, heat effects etc), suicides as well as homicides. Elderly people seem to be at greater risk due to their special characteristics as a vulnerable social group. The aim of this study was to investigate violent deaths (accidents, suicides and homicides) among elderly people in Attica, Greece, during the period 2011-2015 by examining manner of death with respect to demographic data (gender and age) and toxicological examination results. A total of 546 violent deaths among people over 65 years old were included in this study. Autopsy findings along with toxicological examination results were collected from the archives of the Department of Forensic Medicine and Toxicology of the National and Kapodistrian University of Athens. The findings of the study showed that most of the victims were male (63.74%). The overwhelming majority of violent deaths (425 cases) were accidents, 92 cases suicides, and the remaining 29 cases homicides. Drowning was the leading cause of all accidental deaths, followed by road traffic accidents. Hangings prevailed among violent suicide methods and asphyxiation presented as a predominant homicide method.

Newly Developed TV-Based Cognitive Training Games Improve Car Driving Skills, Cognitive Functions, and Mood in Healthy Older Adults: Evidence From a Randomized Controlled Trial

Background: Cognitive training in a laboratory improves car driving skills of older car drivers. However, it remains unclear whether other types of cognitive training at home have beneficial effects on driving skills. Using our developed cognitive training games that can be played on a television with a set-top box in a person's home, we investigated the effects of a 6-week cognitive training program on driving skills, which included on-road evaluation (primary outcome), and cognitive functions and emotional states (secondary outcome) in older people. Methods: In this double-blinded randomized control trial (RCT), 60 older licensed drivers were randomly assigned into one of the two groups: a cognitive training game for car driving (CTCD) group and an active control cognitive training game (ACT) group. Participants in the CTCD group played the CTCD (processing speed, dual attention, and speed prediction) for 20 min in five sessions per week for 6 weeks. Participants in the ACT group played the ACT (selecting the larger number; selecting a number from largest to smallest; play a game of rock, article, scissors) for 20 min in five sessions per week for 6 weeks. We measured driving skills, various cognitive functions, and emotional states before and after the 6-week intervention period. Results: Our main results showed that compared to the ACT group, the CTCD group demonstrated improved driving skills (adjusted p = 0.034). Moreover, the CTCD group demonstrated improved inhibition (stroop, adjusted p = 0.042: reverse Stroop, adjusted p = 0.043) and processing speed performance symbol search (SS), adjusted p = 0.049; digit symbol coding (adjusted p = 0.047), compared to the ACT group. The CTCD group scored higher on vigor-activity mood (adjusted p = 0.041) as measured using the Profile of Mood State. Discussion: This randomized controlled trial provides scientific evidence for the benefits of the 6-week CTCD program on driving skills and cognitive functions, such as processing speed, inhibition, and vigor-activity mood, in healthy older people. Our results suggest that cognitive training is useful to improve the driving skills of older adults. Trial registration: This trial was registered at The University Hospital Medical Information Network Clinical Trials Registry (UMIN 000029769). Registered 31 October 2017, https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000034010.

Primary insomnia patients' performances during simulated car following and urban driving in the afternoon

According to epidemiological studies, insomnia is associated with an increase in risk of traffic accidents. Recent investigations revealed that patients with insomnia had driving performance impairment under monotonous conditions. However, it is unclear whether other driving abilities may be impacted by insomnia, especially those needing more attentional resources than those involved in monotonous driving. Other findings revealed that impaired performances are more likely to occur with the increase of cognitive demands. However, such tests did not reflect difficulties in situations of everyday life expressed by patients with insomnia, such as driving in an urban environment with traffic and critical situations. Therefore, behaviour in situations encountered in everyday life has to be explored. The aim of the present study was to assess driving performances of patients with insomnia in daily routine tasks such as urban and car-following tests. For this purpose, 15 patients with insomnia and 16 good sleepers performed an urban test of driving with original risk scenarios and a car-following test during the middle afternoon. No significant behavioural difference between patients with insomnia and good sleepers has been found in both the urban test and the car-following test, showing that patients with insomnia have no impairment in behaviour implicated in daily contexts driving tasks of short period of time performed in the late afternoon. Although our results provide a first step towards knowledge of behavioural performance during daily routine driving tasks in patients with insomnia, future studies are needed using on-the-road driving tests and/or different population of patients with insomnia before generalisation.

Validating Driver Behavior and Attitude Measure for Older Italian Drivers and Investigating Their Link to Rare Collision Events

The present study aimed to: (a) validate the factor structures of three scales assessing driving behavior, attitudes toward traffic safety (ATTS) and self-regulation in driving, in a sample of Italian older adults, through confirmatory factor analyses and (b) to determine the effectiveness of these measures in predicting the likelihood and the frequency of collision involvements in the following year. A 28-item driver behavior questionnaire (DBQ), a 16-item ATTS, a 21-item extended driving mobility questionnaire (DMQ-A) were administered to 369 active Italian drivers, aged between 60 and 91 years. Results showed a four-factor structure for the DBQ, a five-factor structure for the ATTS and a two-factor structure for the Extended DMQ-A, as the best fitting models. Hurdle model analysis of count data with extra-zeros showed that all factors of DBQ predicted the likelihood of road collisions. Risky behavior, except for aggressive violations, self-regulation and attitudes toward traffic rules were associated with the frequency of collision involvement. The aforementioned three scales seemed to be a useful and concise suite of instruments assessing risky as well as protective factors of driving behavior in elderly.

Evidence Transcranial Direct Current Stimulation Can Improve Saccadic Eye Movement Control in Older Adults

Objectives: Ageing is associated with declines in voluntary eye movement control, which negatively impact the performance of daily activities. Therapies treating saccadic eye movement control deficits are currently lacking. To address the need for an effective therapy to treat age-related deficits in saccadic eye movement control, the current study investigated whether saccadic behaviour in older adults can be improved by anodal transcranial direct current stimulation (tDCS) over the dorsolateral prefrontal cortex using a montage that has been proven to be effective at improving nonoculomotor control functions. Method: The tDCS protocol entailed a 5 cm × 7 cm anodal electrode and an encephalic cathodal reference electrode positioned over the contralateral supraorbital area. In two experiments, healthy older men completed one active (1.5 mA current for 10 min) and one sham stimulation session, with the session order counterbalanced across participants, and eye movement testing following stimulation. In the first experiment, participants rested during the tDCS (offline), whereas in the follow-up experiment, participants engaged in antisaccades during the tDCS (online). Results: Analyses revealed improvements in saccadic performance following active anodal tDCS relative to sham stimulation in the online experiment, but not in the offline experiment, which was presumably due to the activation of the relevant networks during tDCS promoting more targeted effects. Discussion: These outcomes converge with findings pertaining to nonoculomotor cognitive functions, and provide evidence that tDCS can improve saccadic eye movement control in older adults.

Effects of chronic marijuana use on driving performance

OBJECTIVES

The effects of marijuana on driving pose a significant public health concern. More studies on chronic marijuana use in driving are needed. The study objectives were to (1) assess differences in the Standardized Field Sobriety Test (SFST) and driving performance outcomes between chronic medical marijuana users and nonusers and (2) identify a cutoff tetrahydrocannabinol (THC) concentration above which chronic medical marijuana users demonstrate driving impairment.

METHODS

This prospective cross-sectional study assessed 31 chronic marijuana users and 41 nonusers. Rapid Detect Saliva Drug Screen 10-panel was administered to all participants. Participants were given a simple visual reaction time test (SVRT) and SFST consisting of the horizontal gaze nystagmus (HGN), the one leg stand (OLS), and the walk and turn (WAT) tests. The STISIM Drive M100 driving simulator assessed driving performance. Driving parameters included standard deviation of speed (SDS), deviation of mean lane position, off-road accidents, collisions, pedestrians hit, and car-following modulus, delay, and coherence. Cannabinoid blood plasma was obtained from marijuana users.

RESULTS

Marijuana users and nonusers did not differ in age (40.06 ± 13.92 vs. 41.53 ± 15.49, P = .6782). Marijuana users were more likely to fail the SFST (P = .005) and the WAT (P = .012) and HGN (P = .001) components. Marijuana users had slower SVRT (P = .031), less SDS (P = .039), and lower modulus (P = .003). Participants with THC >2 ng/mL (P = .017) and TCH >5 ng/mL (P = .008) had lower SDS. Participants with THC >2 ng/mL (P = .021) and THC >5 ng/mL (P = .044) had decreased modulus.

CONCLUSION

Chronic marijuana users had slower reaction times, deviated less in speed, and had difficulty matching a lead vehicle's speed compared to nonusers. The effects on SDS and modulus were present at cutoffs of 2 and 5 ng/mL.