Driving performance under alcohol in simulated representative driving tasks: an alcohol calibration study for impairments related to medicinal drugs

Long-term effects of daylight saving time on driving fatigue

The study of the relationship between Daylight Saving Time (DST) and road safety has yielded contrasting results, most likely in relation to the inability of crash-database approaches to unravel positive (ambient lighting-related) and negative (circadian/sleep-related) effects, and to significant geographical differences in lighting-related effects. The aim of this study was to investigate the effects of DST on driving fatigue, as measured by driving-based, physiological and subjective indicators obtained from a driving simulator experiment. Thirty-seven participants (73 % males, 23 ± 2 years) completed a series of 50-min trials in a monotonous highway environment: Trial 1 was in the week prior to the Spring DST transition, Trial 2 in the following week, and Trial 3 in the fourth week after the transition. Thirteen participants returned for Trial 4, in the week prior to the Autumn switch to civil time, and Trial 5 in the following week. Significant adverse effects of DST on vehicle lateral control and eyelid closure were documented in Trial 2 and Trial 3 compared to Trial 1, with no statistical differences between Trials 2 and 3. Further worsening in vehicle lateral control was documented in Trials 4 and 5. Eyelid closure worsened up to Trial 4, and improved in Trial 5. Participants were unaware of their worsening performance based on subjective indicators. In conclusion, DST has a detrimental impact on driving fatigue during the whole time during which it is in place. Such an impact is comparable, for example, to that associated with driving with a blood alcohol concentration of 0.5 g/L.

Drinking and driving: A systematic review of the impacts of alcohol consumption on manual and automated driving performance

INTRODUCTION

Almost a third of car accidents involve driving after alcohol consumption. Autonomous vehicles (AVs) may offer accident-prevention benefits, but at current automation levels, drivers must still perform manual driving tasks when automated systems fail. Therefore, understanding how alcohol affects driving in both manual and automated contexts offers insight into the role of future vehicle design in mediating crash risks for alcohol-impaired driving.

METHOD

This study conducted a systematic review on alcohol effects on manual and automated (takeover) driving performance. Fifty-three articles from eight databases were analyzed, with findings structured based on the information processing model, which can be extended to the AV takeover model.

RESULTS

The literature indicates that different Blood Alcohol Concentration (BAC) levels affect driving skills essential for traffic safety at various information processing stages, such as delayed reacting time, impaired cognitive abilities, and hindered execution of driving tasks. Additionally, the driver's driving experience, drinking habits, and external driving environment play important roles in influencing driving performance.

CONCLUSIONS

Future work is needed to examine the effects of alcohol on driving performance, particularly in AVs and takeover situations, and to develop driver monitoring systems.

PRACTICAL APPLICATIONS

Findings from this review can inform future experiments, AV technology design, and the development of driver state monitoring systems.

Metabolomics-based Sleepiness Markers for Risk Prevention and Traffic Safety (ME-SMART): a monocentric, controlled, randomized, crossover trial

BACKGROUND

Too little sleep and the consequences thereof are a heavy burden in modern societies. In contrast to alcohol or illicit drug use, there are no quick roadside or workplace tests for objective biomarkers for sleepiness. We hypothesize that changes in physiological functions (such as sleep-wake regulation) are reflected in changes of endogenous metabolism and should therefore be detectable as a change in metabolic profiles. This study will allow for creating a reliable and objective panel of candidate biomarkers being indicative for sleepiness and its behavioral outcomes.

METHODS

This is a monocentric, controlled, randomized, crossover, clinical study to detect potential biomarkers. Each of the anticipated 24 participants will be allocated in randomized order to each of the three study arms (control, sleep restriction, and sleep deprivation). These only differ in the amount of hours slept per night. In the control condition, participants will adhere to a 16/8 h wake/sleep regime. In both sleep restriction and sleep deprivation conditions, participants will accumulate a total sleep deficit of 8 h, achieved by different wake/sleep regimes that simulate real-life scenarios. The primary outcome is changes in the metabolic profile (i.e., metabolome) in oral fluid. Secondary outcome measures will include driving performance, psychomotor vigilance test, d2 Test of Attention, visual attention test, subjective (situational) sleepiness, electroencephalographic changes, behavioral markers of sleepiness, changes in metabolite concentrations in exhaled breath and finger sweat, and correlation of metabolic changes among biological matrices.

DISCUSSION

This is the first trial of its kind that investigates complete metabolic profiles combined with performance monitoring in humans over a multi-day period involving different sleep-wake schedules. Hereby, we aim to establish a candidate biomarker panel being indicative for sleepiness and its behavioral outcomes. To date, there are no robust and easily accessible biomarkers for the detection of sleepiness, even though the vast damage on society is well known. Thus, our findings will be of high value for many related disciplines.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier NCT05585515, released on 18.10.2022; Swiss National Clinical Trial Portal SNCTP000005089, registered on 12 August 2022.

A Simulation-based Study of the Effect of Brake Light Flashing Frequency on Driver Brake Behavior from the Perspective of Response Time

To prevent vehicle crashes, studies have proposed the use of flashing signals (brake lights or other light indicators) to improve the driver’s response time when the leading vehicle is braking. However, there are no consistent results on the ideal flashing frequency of the brake lights. This study aimed to investigate different brake light flashing frequencies to assess their impact on braking response time. Twenty-four participants aged 25 to 30 were recruited. Two driving speed environments (50 and 80 km/h), three deceleration rates (0.25, 0.6, and 1 g), and four brake light flashing frequencies (0, 2, 4, and 7 Hz) were examined. Braking response time, average braking force, and braking response time ratio were used to evaluate the driving behavior. The results showed that the braking response time and average braking force were affected by the deceleration rate in the 50 km/h driving environment. In the 50 and 80 km/h driving environments, although there were no significant differences among the three deceleration rates, the braking response time decreased by 3–7% under the flashing brake light condition. These findings can be used as a reference for safety designs as well as future studies on driving behavior.

Substance‐use simulation impairs driving capability in patients with cirrhosis regardless of hepatic encephalopathy

Driving is independently affected by cirrhosis and hepatic encephalopathy (HE) and alcohol/substance use, but their concomitant impact is unclear. We aimed to determine the impact of alcohol and other substances on driving‐simulator performance in cirrhosis with and without HE. Outpatients with cirrhosis and controls underwent cognitive testing and driving simulation for the following three conditions: baseline, wearing goggles simulating alcohol intoxication, and wearing goggles simulating opioid/benzodiazepine abuse. Outcomes were number of centerline crossings (CCs) and road‐edge excursions (REEs). We compared controls versus patients with cirrhosis then subjects with cirrhosis with and without HE for all conditions, using generalized linear modeling (GLM). Sixty subjects (17 controls, 43 with cirrhosis [Model for End‐Stage Liver Disease score, 10; 21 subjects with prior HE]) were included. Simulations showed higher CCs and REEs at baseline in patients with cirrhosis with and without HE versus controls. With alcohol‐ and substance abuse‐impairment goggles, CCs increased but REEs decreased in cirrhosis. In the GLM, a time and group interaction was seen (p < 0.001) for CCs and REEs. Patients with cirrhosis showed higher CCs and REEs at baseline than controls (CCs, p = 0.003; REEs, p = 0.0001) and higher CCs (p = 0.03) and lower REEs (p = 0.001) with alcohol‐simulating goggles. All groups were equally impaired with opioid/benzodiazepine‐simulating goggles (CCs, p = 0.49; REEs, p = 0.46). Controls with alcohol‐simulating goggles had similar CCs as the baseline of patients with cirrhosis (p = 0.98). conclusions: Simulating alcohol intake induces greater driving impairment in patients with cirrhosis versus controls, but similar patterns were seen with opioid/benzodiazepine‐simulating goggles. At baseline, patients with cirrhosis have simulator outcomes equivalent to intoxicated controls. Driving simulation with goggles modeling substance abuse could improve insight into driving errors and enhance driving rehabilitation in patients with cirrhosis.

The effects of cannabis and alcohol on driving performance and driver behaviour: a systematic review and meta-analysis

BACKGROUND AND AIMS

Cannabis and alcohol are frequently detected in fatal and injury motor vehicle crashes. While epidemiological meta-analyses of cannabis and alcohol have found associations with an increase in crash risk, convergent evidence from driving performance measures is insufficiently quantitatively characterized. Our objectives were to quantify the magnitude of the effect of cannabis and alcohol-alone and in combination-on driving performance and behaviour.

METHODS

Systematic review and meta-analysis. We systematically searched Academic Search Complete, CINAHL, Embase, Scopus, Google Scholar, MEDLINE, PsycINFO, SPORTDiscus and TRID. Of the 616 studies that underwent full-text review, this meta-analysis represents 57 studies and 1725 participants. We extracted data for hazard response time, lateral position variability, lane deviations or excursions, time out of lane, driving speed, driving speed variability, speed violations, time speeding, headway, headway variability and crashes from experimental driving studies (i.e. driving simulator, closed-course, on-road) involving cannabis and/or alcohol administration. We reported meta-analyses of effect sizes using Hedges' g and r.

RESULTS

Cannabis alone was associated with impaired lateral control [e.g. g = 0.331, 95% confidence interval (CI) = 0.212-0.451 for lateral position variability; g = 0.198, 95% CI = 0.001-0.395 for lane excursions) and decreased driving speed (g = -0.176, 95% CI = -0.298 to -0.053]. The combination of cannabis and alcohol was associated with greater driving performance decrements than either drug in isolation [e.g. g = 0.480, 95% CI = 0.096-0.865 for lateral position variability (combination versus alcohol); g = 0.525, 95% CI = 0.049-1.002 for time out of lane (versus alcohol); g = 0.336, 95% CI = 0.036-0.636 for lateral position variability (combination versus cannabis; g = 0.475, 95% CI = 0.002-0.949 for time out of lane (combination versus cannabis)]. Subgroup analyses indicated that the effects of cannabis on driving performance measures were similar to low blood alcohol concentrations. A scarcity of data and study heterogeneity limited the interpretation of some measures.

CONCLUSIONS

This meta-analysis indicates that cannabis, like alcohol, impairs driving, and the combination of the two drugs is more detrimental to driving performance than either in isolation.

Strong evidence for age as the single most dominant predictor of medically supervised driving test-mini mental status test outcomes provide only weak but significant moderate additional predictive value

Background

With age, medical conditions impairing safe driving accumulate. Consequently, the risk of accidents increases. To mitigate this risk, Swiss law requires biannual assessments of the fitness to drive of elderly drivers. Drivers may prove their cognitive and physical capacity for safe driving in a medically supervised driving test (MSDT) when borderline cases, as indicated by low performance in a set of four cognitive tests, including e.g. the mini mental status test (MMST). Any prognostic, rather than indicative, relations for MSDT outcomes have neither been confirmed nor falsified so far. In order to avoid use of unsubstantiated rules of thumb, we here evaluate the predictive value for MSDT outcomes of the outcomes of the standard set of four cognitive tests, used in Swiss traffic medicine examinations.

Methods

We present descriptive information on age, gender and cognitive pretesting results of all MSDTs recorded in our case database from 2017 to 2019. Based on these retrospective cohort data, we used logistic regression to predict the binary outcome MSDT. An exploratory analysis used all available data (model 1). Based on the Akaike Information Criterion (AIC), we then established a model including variables age and MMST (model 2). To evaluate the predictive value of the four cognitive assessments, model 3 included cognitive test outcomes only. Receiver operating characteristics (ROC) and area under the curve (AUC) allowed evaluating discriminative performance of the three different models using independent validation data.

Results

Using N = 188 complete data sets of a total of 225 included cases, AIC identified age (p < 0.0008) and MMST (p = 0.024) as dominating predictors for MSDT outcomes with a median AUC of 0.71 (95%-CI 0.57–0.85) across different training and validation splits, while using the four cognitive test results exclusively yielded a median AUC of 0.55 (95%-CI 0.40–0.71).

Conclusions

Our analysis provided strong evidence for age as the single most dominant predictor of MSDT outcomes. Adding MMST provides only weak additional predictive value for MSDT outcomes. Combining the results of four cognitive test used as standard screen in Swiss traffic medicine alone, proved to be of poor predictive value. This highlights the importance of MSDTs for balancing between the mitigation of risks by and the right to drive for the elderly.

Silexan does not affect driving performance after single and multiple dose applications: Results from a double-blind, placebo and reference-controlled study in healthy volunteers

Anxiolytic drugs often have sedative effects that impair the ability to drive. Our double-blind, randomized crossover trial investigated the effect of Silexan, a non-sedating, anxiolytic herbal medicinal product, on driving performance in healthy volunteers. Part 1 aimed at demonstrating equivalence between 80 mg/d Silexan and placebo. Part 2 was performed to demonstrate superiority of 160 and 320 mg Silexan over 1 mg lorazepam and included a placebo arm for assay sensitivity. Driving performance was assessed in a validated, alcohol-calibrated simulator test. The primary outcome was the standard deviation of the lane position (SDLP). Secondary outcomes included driving errors and sleepiness. Fifty and 25 subjects were randomized in Parts 1 and 2, respectively. In Part 1, Silexan 80 mg was confirmed to be equivalent to placebo after single administration (equivalence range: δ = ±2 cm). The 95% confidence interval (CI) for the SDLP marginal mean value difference Silexan-placebo for single administration was -1.43; +1.38 and thus similar to the 95% CI of -1.45; +0.79 cm for 7 days' multiple dosing. In Part 2, 95% CIs for SDLP marginal mean value differences to lorazepam were -8.58; -5.42 cm for Silexan 160 mg and -8.65; -5.45 cm for 320 mg (p < 0.001). Confirmatory results were supported by secondary outcomes, where results for Silexan were comparable to placebo and more favorable than for lorazepam. The study demonstrates that single doses of up to 320 mg Silexan and multiple doses of 80 mg/d have no adverse effect on driving performance.

Validity and reliability of a driving simulator for evaluating the influence of medicinal drugs on driving performance

RATIONALE

Although driving simulators (DS) are receiving increasing attention due to concern over traffic accidents under the influences of drugs, few DS are recognized for their reliability and validity. Therefore, the development of an evaluation system using DS for driving performance is urgently needed.

OBJECTIVES

To investigate whether the standard deviation of lateral position (SDLP) increases with blood alcohol concentration (BAC) using a DS with reliability and calculate the SDLP threshold from the difference between BAC levels of 0 and 0.05%.

METHODS

Twenty healthy Japanese men performed the DS tasks up to 60 min in Study 1 and DS tasks twice at 1-week intervals in Study 2. Twenty-six healthy men conducted the same DS tasks under BAC level (0, 0.025, 0.05, and 0.09%) in double-blind, randomized, crossover trial in Study 3. The primary outcome was SDLP in a road-tracking test. The test-retest reliability of DS data was assessed, and the estimated difference in SDLP between BAC levels of 0 and 0.05% was calculated using a linear regression model.

RESULTS

The cumulative SDLP values at 5-min intervals were stable, and the intraclass correlation coefficient for its values was 0.93. SDLP increased with BAC in a concentration-dependent manner. The predicted ΔSDLP value for the difference between BAC levels of 0 and 0.05% was 9.23 cm. No participants dropped out because of simulator sickness.

CONCLUSIONS

The new DS used in these studies has reliability, validity, and tolerability and is considered suitable for evaluating the influence of drugs on driving performance.

Sleep inertia in automated driving: Post-sleep take-over and driving performance

Sleep is emerging as a new driver state in automated driving. Post-sleep performance impairments due to sleep inertia, the transitional phase from sleep to wakefulness that can take up to 30 min, are a potential safety issue. Take-over performance immediately after sleep is impaired and drivers perceive the take-over as critical. The aim of the presented study was to assess take-over behavior immediately after sleep and driving behavior during the 10 min after sleep. A study with N = 31 drivers was conducted in a high-fidelity driving simulator. Take-over performance and driving performance were assessed a) under alert baseline conditions and b) after awakening from electroencephalography-confirmed stable sleep. Take-over performance 15 s after awakening was impaired resulting in more driving errors compared to the alert baseline. Lane keeping was dramatically impaired in the first 3 min after sleep and recovered rapidly. Drivers drove slower after sleep and speed keeping was less stable for at least 10 min. The results suggest that human-machine interaction design should account for the drivers' impaired post-sleep driving performance.

Buckle up!

Die Verkehrsmedizin als Teil der Rechtsmedizin erfüllt in der Schweiz eine wichtige präventive Aufgabe in der Sicherung aller Verkehrsteilnehmer: Sie begutachtet die medizinisch basierte Fahrfähigkeit und Fahreignung. Als empirisch konsolidiertes Querschnittsfach hat sie Informationen aus einer Vielzahl von medizinischen Fachgebieten. Wie reagiert die Verkehrsmedizin aber auf den vermehrten Anspruch evidenzbasierter Gutachten und auf anstehende Herausforderungen?

Über einen historischen Abriss motivierten wir die Vorteile und das Potential einer teilweise durch Fahrsimulation ergänzten Untersuchung und einer dediziert auf Fahrsimulation basierenden, klinisch-prospektiven Forschung.

Neben vorhandener Literatur stützen sich historische Aspekte u.a. auf vorhandene Expertise. Die Bewertung der Fahrsimulation für die Verkehrs- bzw. Rechtsmedizin der Schweiz stützt sich auf die Diskussion selektierter Literatur.

Auftrag und Anspruch der Verkehrsmedizin haben sich mehrfach verändert. Eine übersichtsartige Betrachtung existenter Literatur legt nahe, dass massgeschneiderte Fahrsimulatoren Teil einer modernisierten Verkehrsmedizin sein können, um anstehende Herausforderungen adäquat adressieren zu können. Bisher existiert kein derartiges dediziertes Forschungsinstrument in der Schweiz.

Eine auf verkehrsmedizinische Fragestellungen massgeschneiderte, realitätsnahe und niedrigschwellige Fahrsimulation als Werkzeug für klinische Studien und Individualuntersuchungen verspricht neben einer wissenschaftlichen Produktivität einen umsetzbaren und vermittelbaren Mehrwert für das übergeordnete Ziel der Sicherheit aller Verkehrsteilnehmer.

The effect of cannabidiol on simulated car driving performance: A randomised, double-blind, placebo-controlled, crossover, dose-ranging clinical trial protocol

OBJECTIVE

Interest in the use of cannabidiol (CBD) is increasing worldwide as its therapeutic effects are established and legal restrictions moderated. Unlike Δ9 -tetrahydrocannabinol (Δ9 -THC), CBD does not appear to cause cognitive or psychomotor impairment. However, further assessment of its effects on cognitively demanding day-to-day activities, such as driving, is warranted. Here, we describe a study investigating the effects of CBD on simulated driving and cognitive performance.

METHODS

Thirty healthy individuals will be recruited to participate in this randomised, double-blind, placebo-controlled crossover trial. Participants will complete four research sessions each involving two 30-min simulated driving performance tests completed 45 and 210 min following oral ingestion of placebo or 15, 300, or 1,500 mg CBD. Cognitive function and subjective drug effects will be measured, and blood and oral fluid sampled, at regular intervals. Oral fluid drug testing will be performed using the Securetec DrugWipe® 5S and Dräger DrugTest® 5000 devices to determine whether CBD increases the risk of "false-positive" roadside tests to Δ9 -THC. Noninferiority analyses will test the hypothesis that CBD is no more impairing than placebo.

CONCLUSION

This study will clarify the risks involved in driving following CBD use and assist in ensuring the safe use of CBD by drivers.

Protocol for the development and validation of a driving simulator for evaluating the influence of drugs on driving performance

INTRODUCTION

Although automobile driving is often necessary in daily life, most package inserts for psychotropic drugs in Japan prohibit patients from driving under the influence of medication. This may be partially because no system to evaluate the influence of drugs on driving performance has been established. Standardized evaluation methods have been established in the Netherlands and the United States, but these cannot be implemented in Japan because of differences in road situations, traffic laws, and ethnicities. Therefore, to establish a method to evaluate the influence of drugs on driving performance in Japan, we planned a validation study using alcohol and a driving simulator (DS) and set a clinically meaningful threshold involving the standard deviation of lateral position (SDLP), which is a criterion standard evaluation item.

METHODS

This study was designed as a double-blind, placebo-controlled, randomized, 4-way, fourth-order crossover trial (Williams design). Twenty-four healthy Japanese men aged 21 to 64 years will be recruited through advertisements. The participants will be required to drive daily for over 3 years and to carry the active-type aldehyde dehydrogenase (ALDH) gene polymorphism (ALDH 2*1/*1). Participants will be randomly assigned to 4 groups based on blood alcohol concentration (BAC): 0% (placebo), 0.025%, 0.05%, and 0.09%. The amount of alcohol intake will be calculated based on Widmark formula using a beverage that is a mixture of 40% vodka and orange juice. After a practice period, each examination period will be set with 6-day intervals. The primary outcome is SDLP in a 60-minute road-tracking test using the DS. The secondary outcomes are other evaluation items in the DS tasks and DS sickness and sleepiness according to questionnaire responses. The estimated difference in SDLP between BAC levels of 0.05% and 0% will be calculated using a linear model.

ETHICS AND DISSEMINATION

Ethics approval was obtained from the Ethics Committee at Hakata Clinic and the Nagoya University Medical School Hospital Bioethics Review Committee. The trial results will be disseminated through peer-reviewed publications and international conferences.

TRIAL REGISTRATION

This study was registered at ClinicalTrials.gov NCT 03572985 on June 28, 2018.

Evaluation method regarding the effect of psychotropic drugs on driving performance: A literature review

Although automobile driving is necessary for many people, including patients with mental disorders, the influence of psychotropic drugs on driving performance remains unclear and requires scientific verification. Therefore, the objective of this study was to conduct a review of the literature in order to aid the development of a valid evaluation method regarding the influence of medication on driving performance. We conducted a literature search using two sets of terms on PubMed. One set was related to psychotropic drugs, and the other to driving tests. We excluded reviews and case studies and added literature found on other sites. A total of 121 relevant reports were found. The experiments were roughly divided into on-the-road tests (ORT) and driving simulators (DS). Although highway driving tests in ORT are most often used to evaluate driving performance, DS are becoming increasingly common because of their safety and low cost. The validity of evaluation methods for alcohol should be verified; however, we found that there were few validated tests, especially for DS. The scenarios and measurement indices of each DS were different, which makes it difficult to compare the results of DS studies directly. No evaluation indices, except for SD of lateral position, were sufficiently validated. Although highway ORT are the gold standard, DS were shown to have an increasing role in evaluating driving performance. The reliability of DS needs to be established, as does their validation with alcohol in order to accumulate more high-quality evidence.

Expert-based controllability assessment of control transitions from automated to manual driving

Up to a level of full vehicle automation, drivers will have to be available as a fallback level and take back manual control of the vehicle in case of system limits or failures. Before introducing automated vehicles to the consumer market, the controllability of these control transitions has to be demonstrated. This paper presents a novel procedure for an expert-based controllability assessment of control transitions from automated to manual driving. A standardized rating scheme is developed that allows trained raters to integrate different aspects of driving performance during control transitions (e.g., quality of lateral and longitudinal control, adequateness of signalling to other road users, etc.) into one global controllability measure based on video material of the driving situation. The method is adapted from an existing assessment procedure that has been successfully applied to assess the criticality of driving situations in manual driving conditions (e.g., assessment of substance-induced impairments, assessment of fitness-to-drive of novice drivers). This paper presents the rating procedure, including instructions of how to code relevant qualities of the drivers’ performance with accompanying video-demonstrations, and material used for rater training.

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A rating procedure for an expert-based controllability assessment of control transitions from automated to manual driving based on observation of video material was adapted from an existing method used in studies on manual driving.

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The advantage of this method consists in an integration of different dimensions of driving performance (e.g., operational and tactical driving behaviour, criticality of the situation) into one global controllability measure.

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The method allows an assessment and comparison of diverse take-over scenarios, detached from driver performance variables.

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The accompanying video-based training material allows reproducible and reliable execution of the rating procedure.

Effect of different alcohol levels on take-over performance in conditionally automated driving

Automated driving systems are getting pushed into the consumer market, with varying degrees of automation. Most often the driver's task will consist of being available as a fall-back level when the automation reaches its limits. These so-called take-over situations have attracted a great body of research, focusing on various human factors aspects (e.g., sleepiness) that could undermine the safety of control transitions between automated and manual driving. However, a major source of accidents in manual driving, alcohol consumption, has been a non-issue so far, although a false understanding of the driver's responsibility (i.e., being available as a fallback level) might promote driving under its influence. In this experiment, N = 36 drivers were exposed to different levels of blood alcohol concentrations (BACs: placebo vs. 0.05% vs. 0.08%) in a high fidelity driving simulator, and the effect on take-over time and quality was assessed. The results point out that a 0.08% BAC increases the time needed to re-engage in the driving task and impairs several aspects of longitudinal and lateral vehicle control, whereas 0.05% BAC did only go along with descriptive impairments in fewer parameters.

Effects of Consuming a Low Dose of Alcohol with Mixers Containing Carbohydrate or Artificial Sweetener on Simulated Driving Performance

The Australian National Drug and Alcohol Research Centre (NDARC) devised gender-based drinking recommendations to ensure blood or equivalized breath alcohol concentrations (BrAC) remain <0.050%. However, these may be inappropriate for individuals consuming alcohol without carbohydrate (CHO), which results in higher BrACs. This study investigated the effects of ingesting alcohol with and without CHO on BrACs and simulated driving performance. Thirty-two participants (16 males; age: 23 ± 6 years) completed two randomized single-blinded trials. Participants performed a baseline drive (Drive 1), then an experimental drive (Drive 2), following alcohol consumption (males: 20 g; females: 10 g). Alcoholic beverages contained either 25 g sucrose or aspartame (AS). Driving performance was assessed using lateral control (standard deviation of lane position [SDLP] and number of lane departures) and risk-taking (number of overtaking maneuvers and maximum overtaking speed). BrAC and subjective ratings (e.g., intoxication) were also assessed. BrAC was significantly lower as Drive 2 commenced with CHO compared to AS (0.022 ± 0.008% vs. 0.030 ± 0.011%). Two males provided BrACs >0.050% with AS. Neither beverage influenced changes to simulated driving performance. Ingesting alcohol in quantities advised by the NDARC results in no detectable simulated driving impairment. However, the likelihood of exceeding the legal drink-driving BrAC is increased when alcohol is consumed with artificially-sweetened mixers.

Effects of acute alcohol consumption on measures of simulated driving: A systematic review and meta-analysis

Driving simulators are used in a wide range of research settings to help develop an understanding of driver behavior in complex environments. Acute alcohol impairment is an important research topic for traffic safety and a large number of studies have indicated levels of simulated driving impairment imposed by alcohol across a range of performance outcome variables. The aim of the present study was to examine the impact of acute alcohol consumption on simulated driving performance by conducting a systematic review and meta-analysis of the available evidence. The online databases PubMed (MEDLINE), Web of Science (via Thomas Reuters) and Scopus were searched to identify studies that measured simulated car driving performance under control ('no alcohol' or 'placebo alcohol' ingestion) and intervention (acute alcohol ingestion) conditions, using repeated-measures experimental designs. Primary research outcomes were standard deviation of lane position (SDLP) and standard deviation of speed (SDSP); (total number of lane crossings (LC) and average speed (Speed) were secondary research outcomes). Meta-analytic procedures were used to quantify the effect of acute alcohol consumption on vehicle control, and to determine the influence of methodological variables (i.e. the duration of the simulated driving task, the limb of the BAC curve (ascending vs. descending) and the type of driving simulator employed (i.e. car vs. PC-based)) on the magnitude of the performance change due to alcohol consumption. 423 records were screened, and 50 repeated-measures trials (n=962 participants, 62% male) derived from 17 original publications were reviewed. 37 trials (n=721 participants) used a 'placebo alcohol' comparator to determine the effect of alcohol consumption on SDLP (32/37) and SDSP (22/37). Alcohol consumption significantly increased SDLP by 4.0±0.5cm (95% CI: 3.0, 5.1) and SDSP by 0.38±0.10km⋅h^-1 (95% CI: 0.19, 0.57). Regression analyses indicate BAC (p=0.004) and driving simulator platform (p<0.001) influence the magnitude of the SDLP change, such that higher BAC levels and the use of PC-based driving simulators were associated with larger performance decrements (R²=0.80). The limb of the BAC curve and the duration of the driving task did not significantly alter the magnitude of the performance change. Eleven trials (n=205 participants) used a 'no alcohol' comparator to measure the effect of alcohol consumption on SDLP (10/11); few trials assessed SDSP (3/11). Alcohol consumption resulted in a small significant increase in SDLP under these conditions (standardized difference in means=0.23, 95% CI: 0.06, 0.39). These results demonstrate that lateral (SDLP and LC) and longitudinal (SDSP) vehicle control measures in a driving simulator are impaired with acute alcohol consumption. However, SDLP appears to be a more sensitive indicator of driving impairment than other driving performance variables and the results of the present study support its use as a performance outcome when examining alcohol-induced simulated driving impairment.

Effect of chronic opioid therapy on actual driving performance in non-cancer pain patients

RATIONALE

Chronic non-cancer pain (CNCP) is a major health problem. Patients are increasingly treated with chronic opioid therapy (COT). Several laboratory studies have demonstrated that long-term use of opioids does not generally impair driving related skills. But there is still a lack of studies investigating on-the-road driving performance in actual traffic.

OBJECTIVES

The present study assessed the impact of COT on road-tracking and car-following performance in CNCP patients.

METHODS

Twenty CNCP patients, long-term treated with stable doses of opioid analgesics, and 19 healthy controls conducted standardized on-the-road driving tests in normal traffic. Performance of controls with a blood alcohol concentration (BAC) of 0.5 g/L was used as a reference to define clinically relevant changes in driving performance.

RESULTS

Standard Deviation of Lateral Position (SDLP), a measure of road-tracking control, was 2.57 cm greater in CNCP patients than in sober controls. This difference failed to reach statistical significance in a superiority test. Equivalence testing indicated that the 95% CI around the mean SDLP change was equivalent to the SDLP change seen in controls with a BAC of 0.5 g/L and did not include zero. When corrected for age differences between groups the 95% CI widened to include both the alcohol reference criterion and zero. No difference was found in car-following performance.

CONCLUSIONS

Driving performance of CNCP patients did not significantly differ from that of controls due to large inter-individual variations. Hence in clinical practice determination of fitness to drive of CNCP patients who receive opioid treatments should be based on an individual assessment.

Using alcohol intoxication goggles (Fatal Vision® goggles) to detect alcohol related impairment in simulated driving

OBJECTIVE

Fatal vision goggles (FVGs) are image-distorting equipment used within driver education programs to simulate alcohol-related impairment. However, there is no empirical evidence comparing the behavioral effects associated with wearing FVGs to alcohol intoxication. The purpose of this study was to determine the validity of FVGs in producing alcohol-related impairment in simulated driving.

METHODS

Twenty-two healthy males (age: 23 ± 3 years, mean ± SD) participated in a placebo-controlled crossover design study involving 4 experimental trials. In each trial, participants completed a baseline level simulated driving task followed by an experimental driving task, involving one of 4 treatments: (1) a dose of alcohol designed to elicit 0.080% breath alcohol concentration (BrAC; AB), (2) an alcohol placebo beverage (PB), (3) FVG (estimated % blood alcohol concentration [BAC] 0.070-0.100+), and (4) placebo goggles (PGs). The driving tasks included 3 separate scenarios lasting ∼5 min each; these were a simple driving scenario, a complex driving scenario, and a hazard perception driving scenario. Selected lateral control parameters (standard deviation of lane position [SDLP]; total number of lane crossings [LCs]) and longitudinal control parameters (average speed; standard deviation of speed [SDSP]; distance headway; minimum distance headway) were monitored during the simple and complex driving scenarios. Latency to 2 different stimuli (choice reaction time [CRT]) was tested in the hazard perception driving scenario. Subjective ratings of mood and attitudes toward driving were also provided during each of the trials.

RESULTS

Neither placebo treatment influenced simulated driving performance. Mean BrAC was 0.060 ± 0.010% at the time of driving on the AB trial. Lateral control: In the simple driving scenario, SDLP and LC were not affected under any of the experimental treatments. However, in the complex driving scenario, significantly greater SDLP was observed on both the FVG and AB trials compared to their respective baseline drives. LC increased significantly from baseline on the AB trial only. Longitudinal control: Speed was not affected by any of the experimental treatments; however, SDSP increased significantly from baseline on the FVG trial. A significant reduction in distance headway and minimum distance headway was detected on the FVG trial compared to baseline. Hazard perception: Neither AB nor FVG trials were influential on CRT. Subjective mood ratings were significantly altered on the AB and FVG trials compared to baseline and placebo conditions. Participants reported reduced willingness and ability to drive under the active treatments (AB and FVG) than the placebo treatments (PB and PG).

CONCLUSIONS

FVGs may have some utility in replicating alcohol-related impairment on specific driving performance measurements. Hence, the equipment may offer an alternative approach to researching the impact of alcohol intoxication on simulated driving performance among populations where the provision of alcohol would otherwise be unethical (e.g., prelicensed drivers).