Lane Position Variability Research Articles

Deterioration in Driving Performance During Sleep Deprivation Is Similar in Professional and Nonprofessional Drivers

Objective: There is some suggestion in the literature that professional drivers might self-select to be more resistant to the effects of sleep deprivation; however, this question has not been directly examined. The current laboratory study aimed to compare performance changes during acute sleep deprivation between professional and nonprofessional drivers. Methods: Twenty volunteer male professional drivers and 20 nonprofessional drivers performed a simulated driving task (AusEd) and the Psychomotor Vigilance Task (PVT) during 24 hours of continuous wakefulness. Ratings of subjective sleepiness were also examined. Results: There was a progressive and significant increase in lateral lane position and speed variability on the simulated driving task and an increase in PVT reaction times and lapses after participants had been awake for 17 to 24 hours (Ps < .01). There was no difference in performance changes between the professional and nonprofessional drivers. Conclusions: Professional drivers in this study had the same susceptibility to sleep deprivation as nonprofessional drivers. This finding does not support the concept that professional drivers are resistant to sleep loss.

Effects of Information Filtering on Driving

As Connected Vehicle (CV) communicates information to the driver using safety and non-safety applications, problems can occur when these individual CV applications fail to communicate effectively, or when several CV technologies attempt to communicate with the driver simultaneously. Too much information would increase the driver's workload and levels of distraction resulting in growing threat to driving safety. Connected Vehicle Systems (CVS) afford opportunities to collect and share information about the driving environment, including vehicle state, traffic dynamics, and roadway conditions to infer real time workload demands on the driver and then CVS applications filter the complexity of information presented to that driver.This filter strategy strives to maintain driving performance under high workload traffic conditions by protecting the driver's cognitive resources. The primary objective of the study is to analyze critically how interaction with CVS within different levels of traffic condition influences proxy measures for crash risk in the following variables: i) lane position variability; ii) steering wheel input variability. Analysis results showed that information filtering did have positive safety effect on driving, especially under volatile traffic condition.

A pilot study to evaluate simulated driving performance and cognitive function in healthy subjects and patients with restless legs syndrome

A pilot study to evaluate simulated driving performance and cognitive function in healthy subjects and patients with restless legs syndrome Dan Chen,1 Paula Shaw,2 Daniel M Canafax,1,3 James Catesby Ware4 1XenoPort, Inc., Santa Clara, CA, USA; 2Charles River Northwest, Tacoma, WA, USA; 3Theravance Inc., South San Francisco, CA, USA; 4Division of Sleep Medicine, Eastern Virginia Medical School, Norfolk, VA, USA Objective: Symptoms of restless legs syndrome (RLS) usually occur during the evening and night time, resulting in disrupted sleep and subsequent daytime fatigue. This study compared simulated driving performance, alertness, and cognitive function between healthy subjects and patients with a diagnosis of RLS. Methods: Fifteen healthy subjects and 15 untreated RLS subjects were enrolled and completed two driving tests. The first test occurred at 4 PM followed by the second test at 8 AM the next morning. Outcome measures included lane position variability (LPV), speed variability, frequency of simulated crashes (off-road events or collision), and brake reaction time. Other assessments included visual analog scale (VAS) of alertness and the Brief Assessment of Cognition (BAC). Results: Overall, RLS patients and healthy subjects performed similarly on driving assessments. Two subjects within each group experienced off-road events. RLS patients had less alertness on the VAS than healthy subjects before and after driving assessments. Both groups scored similarly on the cognitive function assessments. Conclusion: Despite reported diminished alertness, RLS patients did not demonstrate impairment in driving or cognitive performance. Keywords: restless legs syndrome, simulated driving performance, cognitive function

Effects of driving experience and sensation-seeking on drivers’ adaptation to road environment complexity

Theories of driving behaviour and behavioural adaptation aim to explain why and how drivers modify their behaviour according to changes in roadway conditions. Elements of a driver’s personality and their level of driving experience may be contributing factors to the likelihood and nature of behavioural adaptation to road environment complexity. The present driving simulator study examined the effects of driving experience and sensation-seeking on drivers’ adaptation to road environment complexity in urban areas. Three increasing levels of road environment complexity served as the experimental manipulation. Compared to drivers with between 1 and 5years of licensed driving experience, drivers with 10years or more experience displayed a greater degree of adaptation to increasingly complex urban environments in terms of reductions in speed. This enabled them to respond more quickly to a safety-relevant peripheral detection task (PDT) in the most complex road environment than a group of drivers with a moderate level (5–10years) of driving experience. Although the effects of sensation-seeking were not consistent across measures, it may interact with level of road complexity in terms of changes in lane position and lane position variability. Collectively, results from this exploratory study suggest that driving experience and low sensation-seeking tendencies may be associated with an enhanced ability to appropriately assess the demands of the road environment. However, the assumed ability of drivers with 10years or more experience to choose a more appropriate speed was only applicable in the most complex road environment.

The Impact of Eye Movements and Cognitive Workload on Lateral Position Variability in Driving

The objective of this work was to understand the relationship between eye movements and cognitive workload in maintaining lane position while driving. Recent findings in driving research have found that, paradoxically, increases in cognitive workload decrease lateral position variability. If people drive where they look and drivers look more centrally with increased cognitive workload, then one could explain the decreases in lateral position variability as a result of changes in lateral eye movements. In contrast, it is also possible that cognitive workload brings about these patterns regardless of changes in eye movements. We conducted three experiments involving a fixed-base driving simulator to independently manipulate eye movements and cognitive workload. Results indicated that eye movements played a modest role in lateral position variability, whereas cognitive workload played a much more substantial role. Increases in cognitive workload decrease lane position variability independently from eye movements. These findings are discussed in terms of hierarchical control theory. These findings could potentially be used to identify periods of high cognitive workload during driving.

Cannabis Effects on Driving Skills

Cannabis is the most prevalent illicit drug identified in impaired drivers. The effects of cannabis on driving continue to be debated, making prosecution and legislation difficult. Historically, delays in sample collection, evaluating the inactive Δ(9)-tetrahydrocannabinol (THC) metabolite 11-nor-9-carboxy-THC, and polydrug use have complicated epidemiologic evaluations of driver impairment after cannabis use. We review and evaluate the current literature on cannabis' effects on driving, highlighting the epidemiologic and experimental data. Epidemiologic data show that the risk of involvement in a motor vehicle accident (MVA) increases approximately 2-fold after cannabis smoking. The adjusted risk of driver culpability also increases substantially, particularly with increased blood THC concentrations. Studies that have used urine as the biological matrix have not shown an association between cannabis and crash risk. Experimental data show that drivers attempt to compensate by driving more slowly after smoking cannabis, but control deteriorates with increasing task complexity. Cannabis smoking increases lane weaving and impaired cognitive function. Critical-tracking tests, reaction times, divided-attention tasks, and lane-position variability all show cannabis-induced impairment. Despite purported tolerance in frequent smokers, complex tasks still show impairment. Combining cannabis with alcohol enhances impairment, especially lane weaving. Differences in study designs frequently account for inconsistencies in results between studies. Participant-selection bias and confounding factors attenuate ostensible cannabis effects, but the association with MVA often retains significance. Evidence suggests recent smoking and/or blood THC concentrations 2-5 ng/mL are associated with substantial driving impairment, particularly in occasional smokers. Future cannabis-and-driving research should emphasize challenging tasks, such as divided attention, and include occasional and chronic daily cannabis smokers.

Cognitive components of simulated driving performance: Sleep loss effects and predictors

Driving is a complex task, which can be broken down into specific cognitive processes. In order to determine which components contribute to drowsy driving impairments, the current study examined simulated driving and neurocognitive performance after one night of sleep deprivation. Nineteen professional drivers (age 45.3±9.1) underwent two experimental sessions in randomised order: one after normal sleep and one after 27h total sleep deprivation. A simulated driving task (AusEd), the psychomotor vigilance test (PVT), and neurocognitive tasks selected from the Cognitive Drug Research computerised neurocognitive assessment battery (simple and choice RT, Stroop Task, Digit Symbol Substitution Task, and Digit Vigilance Task) were administered at 10:00h in both sessions. Mixed-effects ANOVAs were performed to examine the effect of sleep deprivation versus normal sleep on performance measures. To determine if any neurocognitive tests predicted driving performance (lane position variability, speed variability, braking RT), neurocognitive measures that were significantly affected by sleep deprivation were then added as a covariate to the ANOVAs for driving performance. Simulated driving performance and neurocognitive measures of vigilance and reaction time were impaired after sleep deprivation (p<0.05), whereas tasks examining processing speed and executive functioning were not significantly affected by sleep loss. PVT performance significantly predicted specific aspects of simulated driving performance. Thus, psychomotor vigilance impairment may be a key cognitive component of driving impairment when sleep deprived. The generalisability of this finding to real-world driving remains to be investigated.

Efficient driver drowsiness detection at moderate levels of drowsiness

Previous research on driver drowsiness detection has focused primarily on lane deviation metrics and high levels of fatigue. The present research sought to develop a method for detecting driver drowsiness at more moderate levels of fatigue, well before accident risk is imminent. Eighty-seven different driver drowsiness detection metrics proposed in the literature were evaluated in two simulated shift work studies with high-fidelity simulator driving in a controlled laboratory environment. Twenty-nine participants were subjected to a night shift condition, which resulted in moderate levels of fatigue; 12 participants were in a day shift condition, which served as control. Ten simulated work days in the study design each included four 30-min driving sessions, during which participants drove a standardized scenario of rural highways. Ten straight and uneventful road segments in each driving session were designated to extract the 87 different driving metrics being evaluated. The dimensionality of the overall data set across all participants, all driving sessions and all road segments was reduced with principal component analysis, which revealed that there were two dominant dimensions: measures of steering wheel variability and measures of lateral lane position variability. The latter correlated most with an independent measure of fatigue, namely performance on a psychomotor vigilance test administered prior to each drive. We replicated our findings across eight curved road segments used for validation in each driving session. Furthermore, we showed that lateral lane position variability could be derived from measured changes in steering wheel angle through a transfer function, reflecting how steering wheel movements change vehicle heading in accordance with the forces acting on the vehicle and the road. This is important given that traditional video-based lane tracking technology is prone to data loss when lane markers are missing, when weather conditions are bad, or in darkness. Our research findings indicated that steering wheel variability provides a basis for developing a cost-effective and easy-to-install alternative technology for in-vehicle driver drowsiness detection at moderate levels of fatigue.

Driving without awareness: The effects of practice and automaticity on attention and driving

This research examined the development of proceduralised without awareness in a driving simulator by paying participants drive a simulated road regularly over 12 weeks of testing. This longitudinal research paradigm is a significant departure previous studies which have examined drivers in a conscious attentional mode using short experimental sessions or cross-sectional designs comparing expert and novice performance. During each session, participants took two trips on the simulated road; sometimes travelling on a to and from journey on one half of the road, sometimes traversing the entire road in one direction. A range of measures, including driving performance, vehicle detection, perceptual speed regulation, and hazard reactions were collected. The results showed the development of driving patterns and changes in object detection performance indicative of proceduralised driving. Speed and lane position variability quickly decreased with practice, as did participants' subjective experiences of driving difficulty. Performance on an embedded detection task appeared become a proceduralised part of the driving task, becoming highly efficient in later stages of the experiment. The changes in attentional focus and driving performance over time provide new light on previous research findings and allow us critically re-examine several established models of driver behaviour.

Dissociating Eye Movements and Workload on Lateral Lane Position Variability

Recent research suggests that performing a secondary, non-visual task while driving may lead to a reduction in lateral vehicle movement. A plausible explanation for this counterintuitive pattern involves the joint findings that (1) increased cognitive load disrupts eye movements, and (2) eye movements often precipitate steering input. However, a partial dissociation of these factors by Cooper et al. (2009) found that increases in workload and eye movements (at a constant eccentricity) both reduce lateral lane variability. This follow-up study examines the contribution of eye movement eccentricity, under varying workload, on lateral lane position variability. Thirty-two participants drove nine, five minute scenarios in a fixed based driving simulator under varying eye movement and workload conditions. Consistent with previous finding, increased workload led to a decrease in lateral vehicle movement. Interestingly, an effect of visual eccentricity on eye movements was only observed in one of the driving measures. This research suggests that the impact of eye movements on lateral vehicle movement is much smaller than previously hypothesized and that impact of workload is much greater even after accounting for lateral shifts in eye movements.

The Effects of Text Messaging on Young Drivers

This study investigated the effects of using a cell phone to retrieve and send text messages on the driving performance of young novice drivers. Young drivers are particularly susceptible to driver distraction and have an increased risk of distraction-related crashes. Distractions from in-vehicle devices, particularly, those that require manual input, are known to cause decrements in driving performance. Twenty young novice drivers used a cell phone to retrieve and send text messages while driving a simulator. The amount of time that drivers spent not looking at the road when text messaging was up to approximately 400% greater than that recorded in baseline (notext-messaging) conditions. Furthermore, drivers' variability in lane position increased up to approximately 50%, and missed lane changes increased 140%. There was also an increase of up to approximately 150% in drivers' variability in following distances to lead vehicles. Previous research has shown that the risk of crashing while dialing a handheld device, such as when text messaging and driving, is more than double that of conversing on a cell phone. The present study has identified the detrimental effects of text messaging on driving performance that may underlie such increased crash risk. More effective road safety measures are needed to prevent and mitigate the adverse effects on driving performance of using cell phones to retrieve and send text messages.

Daytime Sleepiness and Driving Performance in Patients with Obstructive Sleep Apnea: Comparison of the MSLT, the MWT, and a Simulated Driving Task

To test the reliability of a driving-simulation test for the objective measurement of daytime alertness compared with the Multiple Sleep Latency Test (MSLT) and with the Maintenance of Wakefulness Test (MWT), and to test the ability to drive safely, in comparison with on-road history, in the clinical setting of untreated severe obstructive sleep apnea. N/A. Sleep laboratory. Twenty-four patients with severe obstructive sleep apnea and reported daytime sleepiness varying in severity (as measured by the Epworth Sleepiness Scale). N/A. Patients underwent MSLT and MWT coupled with 4 sessions of driving-simulation test on 2 different days randomly distributed 1 week apart. Simulated-driving performance (in terms of lane-position variability and crash occurrence) was correlated with sleep latency on the MSLT and more significantly on the MWT, showing a predictive validity toward the detection of sleepy versus alert patients with obstructive sleep apnea. In addition, patients reporting excessive daytime sleepiness or a history of car crashes showed poorer performances on the driving simulator. A simulated driving test is a suitable tool for objective measurement of daytime alertness in patients with obstructive sleep apnea. Further studies are needed to clarify the association between simulated-driving performance and on-road crash risk of patients with sleep disordered breathing.

The Contribution of Cognition and Spasticity to Driving Performance in Multiple Sclerosis

Marcotte TD, Rosenthal TJ, Roberts E, Lampinen S, Scott JC, Allen RW, Corey-Bloom J. The contribution of cognition and spasticity to driving performance in multiple sclerosis. Objective To examine the independent and combined impact of cognitive dysfunction and spasticity on driving tasks involving high cognitive workload and lower-limb mobility in persons with multiple sclerosis (MS). Design Single-visit cohort study. Setting Clinical research center. Participants Participants included 17 drivers with MS and 14 referent controls. The group with MS exhibited a broad range of cognitive functioning and disability. Of the 17 patients with MS, 8 had significant spasticity in the knee used to manipulate the accelerator and brake pedals (based on the Modified Ashworth Scale). Interventions Not applicable. Main Outcome Measures A brief neuropsychologic test battery and 2 driving simulations. Simulation 1 required participants to maintain a constant speed and lane position while attending to a secondary task. Simulation 2 required participants to adjust their speed to accelerations and decelerations of a lead car in front of them. Results Patients with MS showed greater variability in lane position (effect size, g=1.30), greater difficulty in maintaining a constant speed ( g=1.25), and less ability to respond to lead car speed changes ( g=1.85) compared with controls. Within the MS group, in a multivariate model that included neuropsychologic and spasticity measures, cognitive functioning was the strongest predictor of difficulty in maintaining lane position during the divided attention task and poor response time to lead car speed changes, whereas spasticity was associated with reductions in accuracy of tracking the lead car movements and speed maintenance. Conclusions In this preliminary study, cognitive and physical impairments associated with MS were related to deficits in specific components of simulated driving. Assessment of these factors may help guide the clinician regarding the types of driving behaviors that would put patients with MS at an increased risk for an automobile crash.

Effect of Wireless Communication and Entertainment Devices on Simulated Driving Performance

An analysis of the effect of wireless telephone communication using text and voice modalities as well as an Apple iPod on lane keeping, speed, speed variability, lateral speed, and lane position variability was conducted with a driving simulator. Participants (young adult licensed drivers) drove in an unusually curvy simulated driving environment while using wireless devices, controlling an iPod, and participating in conversations and word games. As expected on the basis of previous research, lane-keeping performance was robust for voice communication tasks; however, the text messaging and iPod tasks that required significant manual manipulation of the device resulted in significant decrements in lane-keeping performance. In addition, all wireless communication tasks and the iPod task resulted in significant increases in speed variability throughout the driving scenario. Lateral speed increases occurred for all wireless communication tasks other than the cellular phone conversation as well as the iPod task. Increases in lane position variability were observed for the text messaging conditions. In addition to establishing the dramatic performance decrement caused by text messaging tasks, this experiment suggests that driving performance may be affected by distraction in ways not captured by lane-keeping measures alone and explores potential alternative measures of driving performance that may be useful for identifying and quantifying the effects of distracted driving.

The impact of in-car displays on drivers in neighbouring cars: Survey and driving simulator experiment

Legislation against drivers seeing an audiovisual display in their own vehicle does not prevent them from seeing audiovisual displays (such as those used with entertainment systems) in neighbouring vehicles. Resulting cognitive and visual distraction is likely to impair driving, but research is lacking. We conducted a survey ( N = 61) assessing whether drivers have seen and attended to audiovisual entertainment displays in other vehicles. In order to assess the effect of any such distraction on driving, we conducted a driving simulator experiment ( N = 28) in which each participant completed drives under four conditions: (1) while a laptop computer positioned as if in a neighbouring vehicle displayed no audiovisual entertainment materials; (2) while the laptop displayed entertainment materials, and given instructions to attend the materials; (3) while the laptop displayed entertainment materials, and given instructions to ignore the materials; (4) while the laptop displayed entertainment materials, and given no instructions. Thirty-one percent of survey respondents reported having ever seen an entertainment display. Amongst those who were driving at the time of last sighting, 87.5% reported having paid at least “a little” attention to the display. In the simulator experiment, drivers in the “attend” condition demonstrated lower mean speeds, lower variability in throttle input, greater variability in lane position on a curvy road section, and slower deceleration in response to a pedestrian, than those in the baseline condition. Results suggest that drivers pay attention to displays in neighbouring vehicles and this may impair driving. The negative impacts of audiovisual displays as external-to-vehicle distractors might by reduced by design innovations, and legislation limiting visibility of audiovisual displays to the drivers of other vehicles should be considered.

Daytime driving simulation performance and sleepiness in obstructive sleep apnoea patients

Background Sleepiness related car accidents are common in obstructive sleep apnoea syndrome (OSAS) patients. The objective measurements of sleepiness used in clinical setting quantify the tendency to fall asleep in quiet situations that are completely different from driving. Methods We studied 30 OSAS patients with subjective (subjective sleepiness scales) and objective (multiple sleep latency test, MSLT) sleepiness measurements, associated with driving simulation test (DST), previously validated in young healthy subjects. The results of subjective and objective sleepiness tests were compared with simulated driving performance in order to evaluate the suitability of our DST for measuring alertness. Results Subjective and objective sleepiness measurements were significantly correlated with driving performance on the simulator. The most significant correlates of sleepiness were the measures of the primary vehicle control task on the simulator: lane position variability and crash data. The comparison of DST and MSLT results suggested our driving simulated approach could be used to evaluate daytime sleepiness in the clinical setting of OSAS patients. Conclusions Our DST is a suitable objective tool to detect sleepiness in OSAS patients, and could be useful in the clinical setting of sleep medicine and research.

Prevention of Rear-End Crashes in Drivers with Task-Induced Fatigue through the Use of Auditory Collision Avoidance Warnings

Driver fatigue is associated with increased lane position variability, decreased response time and increased crash rate. Collision avoidance systems (CASs), which are currently installed in many vehicles, have been shown to reduce the crash rates of alert drivers. The current investigation examined the effectiveness of two auditory CAS warnings for reducing crash rates in fatigued young and older drivers faced with a potential rear-end collision. Relative to a no-warning condition, auditory CAS warnings reduced overall crash probability. The presence of a CAS warning was particularly beneficial to reducing crashes in older drivers. Results of this study indicate that auditory CAS warnings may help reduce fatigue-related rear-end crashes, particularly among older drivers.

Behavioural adaptation to adaptive cruise control (ACC): implications for preventive strategies

This test-track study assessed whether adaptive cruise control (ACC) induces behavioural adaptation in drivers. Eighteen experienced drivers drove a test vehicle while following a lead vehicle in three counterbalanced conditions: No ACC (self-maintained average headway of 2 s), ACC-Short (headway of 1.4 s) and ACC-Long (headway of 2.4 s). Results demonstrate that ACC can induce behavioural adaptation in drivers in potentially safety-critical ways. Compared to driving unsupported, participants located significantly more items per minute on a secondary task when using ACC, while their response times to a hazard detection task increased. This effect was particularly pronounced in those scoring high on a sensation-seeking scale. Using ACC resulted in significantly more lane position variability, an effect that was also more pronounced in high sensation-seekers. Drivers' trust in ACC increased significantly after using the system, and these ratings did not change despite a simulated failure of the ACC system during the ACC-Long condition. Response time to the simulated ACC failure was related to a driver's locus of control: Externals intervened more slowly than Internals. All drivers reported relying on the ACC system to keep their vehicle at a safe distance from the lead vehicle. Results are consistent with similar research conducted on lane departure warning systems. Driver awareness training is a potential preventive strategy that could minimize the behavioural adaptation associated with novel in-vehicle systems such as ACC.

Driving Simulation with EEG Monitoring in Normal and Obstructive Sleep Apnea Patients

To measure simulated driving performance in obstructive sleep apnea patients and its relationship with EEG defined attention lapses. Prospective, mixed design comparing apnea patients and control subjects over a 60-minute driving simulation task while continuously recording both driving performance and EEG measures. Sleep disorders center. 15 polysomnographically diagnosed obstructive sleep apnea patients (mean age 42 +/- 6 yrs.) and 15 healthy volunteers (mean age 38 +/- 6 yrs.). NA. A computer based driving simulator recorded lane position variability, speed variability, steering rate variability, and crash frequency. The frequency and duration of EEG-defined attention lapses were also measured. The results demonstrated that the apnea group had significantly greater variability in lane position, steering rate, and speed than the control group. The apnea group also had more crashes. In addition, the apnea group had more EEG-defined attention lapses of longer duration. Except for speed and steering rate variability, these differences increased over the 60-minute task. Measures of lane position variability and crash frequency had a significant positive correlation with attention lapse frequency and duration. The driving simulation task unmasked and quantified marked performance impairments in the sleep apnea group that increased over time. The poor performance appeared related to the EEG-defined attention lapses. Lane position variability appeared to be the most sensitive measure for assessing and quantifying impairment. This study suggests that poorer driving performance and crashes are not entirely due to overt sleep, but inattention due to sleepiness.