Impairment Of Driving Performance Research Articles

6 Back-To-Drive Project. Assessment of Fitness-To-Drive in Older and Cognitively Impaired Adult Drivers: Adaptation of the on-Road Driving Observation Schedule to Simulation-Based Environments

Objective:Cognitive, motor and sensory deficits associated with aging, and with some neurological conditions such as acquired brain injury, may lead to severe driving performance impairment. While rehabilitation and driver assistance technologies may improve driving performance, the assessment of the actual fitness-to-drive of these people is challenging. Office-based neuropsychological/physical tests are considered insufficient to understand one’s ability to drive. The gold standard is the on-road assessment with dual control cars, superior in ecological validity, but expensive, stressful, and potentially unsafe. Valid, more cost-effective solutions for a safer, more accurate, standardized assessment of fitness-to-drive are currently needed. Modern and sensorized driving simulators offer key advantages, such as the possibility of exposing drivers to several relevant driving scenarios, including hazard situations, and of assessing their driving performance without being physically at risk. However, the extraction and direct interpretation of existing simulator-produced data may require specialized data processing skills or simulation expertise. To overcome this, we have developed an easy-to-use, pencil-and-paper observational instrument. The Sim-DOS is an adaptation of the widely used instrument to assess “natural driving”, the Driving Observation Schedule (DOS; Vlahodimitrakou et al., 2013).Participants and Methods:Via expert consensus, DOS targeted behaviors were adapted to a simulated-based environment (signaling, observation of environment, speed regulation, slow or unsafe reaction, distance interpretation, vehicle/lane positioning), and the Sim-DOS scores calculation (based on errors while doing such behaviors) was adapted from DOS to include hazard situations (HS, 0-100) and free driving (FD, 0-°°) scores. The instrument was then piloted with a sample of 35 older adults, along with the collection of simulator-produced data on number of harsh events and driving speed. Participants drove two consecutive 20-minutes long scenarios, with low and high traffic density (LTD, HTD). In each scenario, there were periods with and without potentially hazard situations.Results:Assessments were performed by two independent trained observers, producing substantial inter-rater reliability (intra-class correlation coefficients above 0.94). Participants (70.7±4.1 years old, 60% male, 46.1±6.7 years of driving experience) were mostly regular drivers (74%). However, psychomotor skills of the majority were compromised, with only one participant being above the 80th percentile in the reaction times test of the national mandatory driving assessment. When exposed to hazard situations, most of the participants (94.1%) did not perform well, independently of traffic density, with average Sim-DOS-HS scores of 87.1±9.7 (out of 100, t-values>7.3, p-values<.05).Compared to LTD scenarios, in HTD scenarios participants drove less smoothly (HTD:0.97±1.24 vs. LTD:0.33±0.58 of harsh events, Z=3.1, p<.05). However, they also drove slower (HTD:82.41±27.43 vs. LTD:103.55±14.61 km/h, t=5.2, p<.05), improving their ability to manage hazard situations, and therefore producing higher than expected Sim-DOS scores (HTD:87.05±10.28). During free driving, participants performed worse under LTD conditions (Sim-DOS-FD scores: HTD:11.68±6.20 vs. LTD:14.40±9.58, t=2.15, p<.05) as they drove at higher speed (HTD:85.01±24.28 vs. LTD:104.70±11.94 km/h, t=5.8, p<.05), although they did it more smoothly (HTD:1.94±3.74 vs. LTD:0.45±0.74 harsh events, Z=2.65, p<.05).Conclusions:Our study provides a validated driving assessment tool for use in driving simulators that will allow a safer, more ecologic, holistic and informative evaluation of the fitness-to-drive of older adults and neurological patients.

095 Steering Wheel Angle Excursions as a Measure of Fatigue-Related Driver Performance Impairment

Abstract Introduction Fatigue from sleep loss and circadian misalignment causes automobile driving performance impairment. Metrics based on steering wheel angle, which is straightforward to measure, could be used to quantify this impairment. As the tail of the distribution of steering wheel angles (absolute magnitude of deviation from center) increases with fatigue, we investigated whether driving performance impairment could be quantified based on the prevalence of steering wheel excursions beyond a given angle threshold. We used data from two published laboratory studies of simulated shift work, in which fatigue remained low during day shifts but increased across time awake during night shifts. Methods N=37 healthy adults (ages 26.8±5.2y; 25 men) were assigned to a simulated night shift schedule (awake 20:00-10:00) or day shift schedule (awake 08:00-22:00; study 1 only). After an adaptation period, participants underwent two 5-day shift cycles with an intervening rest period. Driving performance was measured on a high-fidelity simulator during adaptation (data not used) and four times at 3h intervals during each shift day. Every drive involved 30min driving at 55mph, including ten 0.5mi uneventful straightaways being considered here. Steering wheel angle was measured at 72Hz (study 1) or 60Hz (study 2). A total of 1,471 drives (31,394,498 angle measurements) were available for analysis. Results We investigated angle thresholds across 0.01-0.25rad in 0.01rad intervals and counted the corresponding number of threshold excursions in each drive for each participant. For study 1, we applied mixed-effects ANOVA with fixed effects for condition and time awake, and their interaction, and determined the local effect size for interaction. A 0.03rad (1.7°) threshold yielded the greatest effect size, f²=0.031 (small). For this threshold, we repeated the analysis using the data from both studies, controlling for study. The interaction was significant (F[3,1428]=13.23, p<0.001), showing low driving impairment across time awake during day shifts but increasing impairment across time awake during night shifts. Conclusion The prevalence of steering wheel excursions beyond a 1.7° angle threshold yielded sensitivity to fatigue-related driving performance impairment during simulated night shifts. Further research will extend our results to driving through curves and with greater fatigue levels. Support (if any) FMCSA DTMC75-07-D-00006

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.

Quantitative sleep EEG and polysomnographic predictors of driving simulator performance in obstructive sleep apnea

ObjectivesTo improve identification of obstructive sleep apnea (OSA) patients at risk of driving impairment, this study explored predictors of driving performance impairment in untreated OSA patients using clinical PSG metrics, sleepiness questionnaires and quantitative EEG markers from routine sleep studies. MethodsSeventy-six OSA patients completed sleepiness questionnaires and driving simulator tests in the evening of their diagnostic sleep study. All sleep EEGs were subjected to quantitative power spectral analysis. Correlation and multivariate linear regression were used to identify the strongest predictors of driving simulator performance. ResultsAbsolute EEG spectral power across all frequencies (0.5–32Hz) throughout the entire sleep period and separately in REM and NREM sleep, (r range 0.239–0.473, all p<0.05), as well as sleep onset latency (r=0.273, p<0.017) positively correlated with driving simulator steering deviation. Regression models revealed that amongst clinical and qEEG variables, the significant predictors of worse steering deviation were greater total EEG power during NREM and REM sleep, greater beta EEG power in NREM and greater delta EEG power in REM (range of variance explained 5–17%, t range 2.29–4.0, all p<0.05) and sleep onset latency (range of variance explained 4–9%, t range 2.15–2.5, all p<0.05). ConclusionsIn OSA patients, increased EEG power, especially in the faster frequency (beta) range during NREM sleep and slower frequency (delta) range in REM sleep were associated with worse driving performance, while no relationships were observed with clinical metrics e.g. apnea, arousal or oxygen indices. SignificanceQuantitative EEG analysis in OSA may provide useful markers of driving impairment risk. Future studies are necessary to confirm these findings and assess the clinical significance of quantitative EEG as predictors of driving impairment in OSA.

Prevalence of and Factors Associated with Distraction Among Public Transit Bus Drivers

Objective: Recent research has suggested that driver distraction is a major cause of driving performance impairment and motor vehicle collisions. Research on the topic has focused on passenger vehicles, with studies suggesting that drivers may be distracted nearly 33 percent of the time spent driving. To date, no study has examined the prevalence of distraction specifically among public transit bus drivers.Methods: Over a 3-month period, trained investigators observed and recorded distraction behaviors of bus drivers. Distraction prevalence was compared by route characteristics (e.g., geographic area, travel speed) using chi-square test. A general estimating equation logistic regression was used to estimate P values for distraction prevalence by driver demographics.Results: Overall, there was a 39 percent prevalence of distraction. The most prevalent distractions were due to interactions with another passenger. Distractions were more prevalent among drivers <30 years of age or ≥50 years of age, on city streets or highways (relative to residential streets), and when there were more than 20 passengers. Distractions were the least prevalent in suburban areas, with the highest prevalence observed in city centers and rural areas.Conclusions: Driver distraction is a common problem for public transit bus drivers, mainly due to other passengers. Drivers should be educated on the hazards of distracted driving and on ways to avoid distraction.

Subjective Fatigue and Performance Variation Correlation During Simulated Driving Tasks

During prolonged driving tasks, fatigue increases and driving performance becomes impaired. To investigate variation of driver fatigue and driving performance, 14 driving simulator test subjects were asked to complete a questionnaire designed to subjectively quantify fatigue levels. Driver fatigue was estimated in several aspects such as ability to drive safely, drowsiness, and physical fatigue symptoms. Quantitative driving performance was evaluated by measuring steering wheel, lateral position, and speed control parameters. The results showed significant increase in subjective driver fatigue and driving performance impairment following simulated driving sessions. Based on questionnaire scores, a driver fatigue indicator was developed. Analysis of this indicator revealed that subjective fatigue increased rapidly during the first 45 minute session, and more gradually during the remaining two sessions. Short breaks between sessions resulted in temporary fatigue recovery. Increased standard deviations for steering wheel rate, lateral velocity, and average speed indicated similar quantitative driving performance impairment. Comparison of subjective scores with standard deviation of acceleration indicates a possible relationship between the increased subjective fatigue and impaired driving performance.

Driving performance impairments due to hypovigilance on monotonous roads

AbstractDrivers’ ability to react to unpredictable events deteriorates when exposed to highly predictable and uneventful driving tasks. Highway design reduces the driving task mainly to a lane-keeping manoeuvre. Such a task is monotonous, providing little stimulation and this contributes to crashes due to inattention. Research has shown that driver’s hypovigilance can be assessed with EEG measurements and that driving performance is impaired during prolonged monotonous driving tasks. This paper aims to show that two dimensions of monotony – namely road design and road side variability – decrease vigilance and impair driving performance. This is the first study correlating hypovigilance and driver performance in varied monotonous conditions, particularly on a short time scale (a few seconds). We induced vigilance decrement as assessed with an EEG during a monotonous driving simulator experiment. Road monotony was varied through both road design and road side variability. The driver’s decrease in vigilance occurred due to both road design and road scenery monotony and almost independently of the driver’s sensation seeking level. Such impairment was also correlated to observable measurements from the driver, the car and the environment. During periods of hypovigilance, the driving performance impairment affected lane positioning, time to lane crossing, blink frequency, heart rate variability and non-specific electrodermal response rates. This work lays the foundation for the development of an in-vehicle device preventing hypovigilance crashes on monotonous roads.

Consistency and sensitivity of lane change test according to driving simulator characteristics

The aim, here, is to evaluate consistency and sensitivity of the lane change test (LCT), which is the subject of a proposed ISO standard. The method is intended to estimate driver distraction while a secondary task is being performed, by measuring performance degradation on a primary driving-like task. An experiment was conducted in two experimental contexts: a fixed-base driving simulator and a personal computer (PC) (including pedals and steering wheel), and with two auditory and two visual–manual secondary tasks. Three performance measures were calculated: adapted mean deviation, correct lane change (LC) ratio and mean delay in LC initiation. The effect of experimental context was significant. The trajectory, measured by the adapted mean deviation, was significantly better on the simulator and the percentage of correct LC higher. This difference might be explained by the greater immersion of the driver in the driving scene, which led to easier control of the trajectory in the simulator. Conversely, participants initiated quicker responses to signs when using the PC, to the detriment of trajectory control. The LCT was also proved to be sensitive enough to evaluate driving performance impairment because of the simultaneous performance of secondary tasks, even if it failed to differentiate all of them.

Simulated Driving and Attention of Repeat Users of MDMA and THC Compared with THC Users and Non-Drug-Using Controls

The aim of the study is to assess if cognitive impairments in abstinent users of methylenedioxymethamphetamine (MDMA) are due to repeated use of MDMA or concurrent drugs of abuse and how these impairments interfere with key activities of daily life such as automobile driving. Simulated driving performance and attention of 12 users of MDMA and marijuana [tetrahydrocannabinol (THC)] (MDMA/THC), 15 THC users, and 15 non-drug-using, age-matched controls were compared. THC users’ mean speed reduction in response to passing a car parked on the shoulder of the road was 7 mph (11.3 km/h) less than that of controls. Compared with non-drug-using controls, the MDMA/THC users were less able to mitigate the effects of an illegal intersection incursion by another vehicle and entered the collision at a higher speed (42 versus 26 mph). In real life, this 16-mph (26-km/h) difference would increase the likelihood of injuring parties in both colliding vehicles. Processing speed and attention did not differ between groups; this suggests that the lower speed reduction in the MDMA/THC users was more likely due to executive function impairments (incorrect situation interpretation and awareness) than to reduced processing speed. In conclusion, compared with non–drug users, MDMA/THC users may be at a greater risk for driver performance errors that lead to crashes. Because collision speed did not differ between MDMA/THC users and THC users, a specific role of MDMA as opposed to THC toxicity in driving performance impairment remains to be established.

Assessing driver status: A demonstration experiment on the road

Twenty subjects completed an on-the-road experiment that consisted of two parts on two separate days. One was a one-hour driving test under the influence of alcohol (BAC < = 0.05%), the second a two-and-a-half-hour driving test under vigilance conditions. Impairment of driving performance was measured in a car-following test as well as in a standard driving test. Changes in relevant physiological parameters, such as ECG and EEG, reflected changes in driver status and predicted driving performance impairment.

Experimental studies of driving performance impairment by medications

Experimental studies of driving performance impairment by medications