Effects of alcohol (BAC 0.5‰) and ecstasy (MDMA 100 mg) on simulated driving performance and traffic safety

Driving under the influence of cocaine and MDMA: Relationship between blood concentrations and results from clinical test of impairment

The general use of cocaine is increasing in recent years, while the trend for 3,4-methylenedioxymethamphetamine (MDMA) is less clear. The relationship between blood concentrations and impairment is poorly understood, which complicates interpretation. The aims of this study were to report prevalence and blood concentrations of cocaine and MDMA in drugged drivers, and to investigate the relationship between blood concentrations and impairment. Samples of whole blood were collected from apprehended drivers in the period 2000-2022, and a clinical test of impairment (CTI) was simultaneously performed. The samples were initially analyzed for cocaine and MDMA using gas chromatography-mass spectrometry (until 2009 and 2012, respectively), and later using ultra-high-performance liquid chromatography-tandem mass spectrometry. Overall, cocaine was detected in 2,331 cases and MDMA in 2,569 cases. There were 377 and 85 mono cases of cocaine and MDMA, respectively. In the mono cases, the median cocaine concentration was 0.09 mg/L (range: 0.02-1.15 mg/L), and 54% of the drivers were clinically impaired. The median MDMA concentration was 0.19 mg/L (range: 0.04-1.36 mg/L), and 38% were clinically impaired. There was a statistically significant difference in the median cocaine concentration between drivers assessed as not impaired (0.07 mg/L) and drivers assessed as impaired (0.10 mg/L) (P = 0.009). There was also a significant effect of the blood concentration of cocaine (adjusted odds ratio [aOR] = 6.42, 95% confidence interval [CI] = 1.13-36.53, P = 0.036) and driving during the evening/night-time (aOR = 2.17, 95% CI = 1.34-3.51, P = 0.002) on the probability of being assessed as impaired on the CTI. No significant differences were found for MDMA. Many drivers are not assessed as impaired on a CTI following cocaine or especially MDMA use. For cocaine, a relationship between blood concentrations and impairment was demonstrated, but this could not be shown for MDMA.

Predicting changes in driving performance in individuals who use cannabis following acute use based on self-reported readiness to drive

OBJECTIVE

It is unclear to what extent individuals who use cannabis can accurately assess their ability to drive safely following cannabis use, and lack of understanding as to what factors influence changes in driving performance following cannabis use. This research explores whether self-reported readiness to drive (RTD) and previous experience (PE) using cannabis within 2 h of driving can predict observed changes in driving performance following acute cannabis use.

METHODS

Individuals who used cannabis at least monthly completed a baseline simulated drive, were dosed with cannabis of approximately 6.18% THC, then drove at approximately 30-minutes, 90-minutes, and 180-minutes post-dose. Before each drive, participants were asked if they felt safe to drive (on real roadways, not the simulator), a yes/no question (RTD-yes/RTD-no). Venous blood was drawn at baseline and approximately 15-minutes post-dose. Cannabis use history was obtained and included whether the participant had ever driven within 2 h of use (PE-yes/PE-no) and how many days out of the past 30 they had done so (NPD). Drives were segmented into events delineated by changes in the driving environment. Within events, standard deviation of lateral position (SDLP), average speed, and number of lane departures were calculated, and differences from baseline were modeled using mixed-effects regression. Models considered covariates of time, event, and speed, and used RTD-yes/RTD-no, PE-yes/PE-no, NPD, and their interactions as potential predictors. Conditional R2 was used to compare the predictive ability of RTD versus change in Delta-9-THC.

DATA SOURCES

Data were collected from 30 individuals who use cannabis and included cannabis use patterns, driving behaviors after use, self-reported RTD, measures of driving performance, and cannabinoid blood levels.

RESULTS

RTD-no predicted a 2.60 cm increase in SDLP relative to baseline (95 % CI: 0.43, 4.73, p = 0.018). Average speeds generally decreased relative to baseline, except for RTD-yes with PE-yes (+1.08 mph, 95 % CI: 0.05, 2.11). NPD predicted increased speed among RTD-yes (+0.11 mph per additional day, 95 % CI: 0.01, 0.22) and decreased speed among RTD-no (-0.06 mph per additional day, 95 % CI: -0.18, 0.32). The difference in these effects was statistically significant (p = 0.038). RTD, PE, and NPD were not significant predictors of changes in number of lane departures. For all outcomes, models using RTD achieved higher conditional R2 than models that replaced this variable with change in Delta-9-THC. Differences were most prominent when modeling change in speed with NPD (R2=0.544 with RTD vs. R2=0.481 with change in Delta-9-THC).

SIGNIFICANCE OF RESULTS

These results suggest individuals who use cannabis can somewhat self-identify when they are likely to exhibit greater degraded lateral control, although RTD does not fully explain observed degradation in performance. Past research suggests drivers may reduce speed to compensate for recognized impairment following acute cannabis use. Our findings suggest this to be true for those who reported never having previously driven within 2 h of cannabis use or reported RTD-no, but not for those who had previously driven within 2 h of cannabis use and reported RTD-yes. This indicates compensatory behavior is not uniform and helps focus public health outreach efforts.

Evaluating the effect of drunk driving on fatal injuries among vulnerable road users in Taiwan: a population-based study

Background

Most studies have focused on injuries sustained by intoxicated drivers themselves, but few have examined the effect of drunk driving on injury outcomes among VRUs (vulnerable road users) in developing countries. This study aims to evaluate the effect of drunk driving on fatal injuries among VRUs (pedestrians, cyclists, or motorcyclists).

Methods

The data were extracted from the National Taiwan Traffic Crash Dataset from January 1, 2011, to December 31, 2019. Crashes involving one motorized vehicle and one VRU were considered. This study examines the effect of drunk driving by estimating multivariate logistic regression models of fatal injuries among VRUs after controlling for other variables.

Results

Among 1,416,168 casualties, the fatality rate of VRUs involved in drunk driving was higher than that of general road users (2.1% vs. 0.6%). Drunk driving was a significant risk factor for fatal injuries among VRUs. Other risk factors for fatal injuries among VRUs included VRU age ≥ 65 years (adjusted odds ratio [AOR]: 5.24, 95% confidence interval [CI]: 5.53–6.07), a nighttime accident (AOR: 4.52, 95% CI: 4.22–4.84), and being hit by a heavy-duty vehicle (AOR: 2.83, 95% CI: 2.26–3.55). Subgroup analyses revealed a linear relationship between driver blood alcohol concentration (BAC) and the risk of fatal injury among motorcyclists. Motorcyclists exhibited the highest fatality rate when they had a BAC ≤ 0.03% (AOR: 3.54, 95% CI: 3.08–4.08).

Conclusion

Drunk driving was associated with a higher risk of fatality for all VRUs. The risk of fatal injury among motorcyclists was linearly related to the BAC of the drunk drivers. Injuries were more severe for intoxicated motorcyclists, even those with BAC ≤ 0.03%, which is within the legal limit.

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.

Driving under the influence of drugs: Correlation between blood psychoactive drug concentrations and cognitive impairment. A narrative review taking into account forensic issues

Driving under the influence of alcohol has been shown to increase the risk of involvement in road traffic collisions (RTCs) however, less is known about the effects of illicit drugs, and a clear correlation between drug concentrations and RTC risk is still debated. The goal of this narrative review is to assess the current literature regarding the most detected psychoactive drugs in RTC (ethanol, amphetamines, cannabis, opioids and cocaine), in relation to driving performance. Evidence on impaired driving due to psychoactive substances, forensic issues relating to the assessment of the impact of drugs, blood cut-off values proposed to date as well as scientific basis for proposed legislative limits are discussed. At present there is no unequivocal evidence demonstrating a clear dose/concentration dependent impairment in many substances. Per se and zero tolerance approaches seem to have negative effect on drugged driving fatalities. However, the weight of these approaches needs further investigation.

Lowering the legal alcohol limit in Belgium: Potential effects on the number of traffic victims

BACKGROUND

Since 1994, the legal limit of Blood Alcohol Concentration (BAC) is 0.5 g/L for the general drivers' population in Belgium. Since 2015, this limit has been lowered to 0.2 g/L for professional drivers. So far, no specific limitation has been adopted for novice drivers in Belgium. Recently, two bills were submitted to the House of Representatives: the first one proposed to impose a zero-limit for every driver, the second one proposed to restrict this zero-limit only to novice drivers.

OBJECTIVE

The present study evaluated the potential impact of the two bills that aim to reduce the legal BAC limit from 0.5 to zero, either for all drivers or for novice drivers only. We elaborated three scenarios related to the BAC categories for which lowering the legal BAC limit to zero would affect drink-driving behaviour: "Targeted BAC levels" scenario assumed that the new policy would impact only the specifically targeted BAC category, i.e., drivers in the category BAC below 0.5 g/L. "Extended impact" scenario corresponded to the "Targeted BAC levels" scenario to which we added a "halo effect" on drivers in the BAC category "0.5 g/L ≤ BAC < 0.8 g/L". "Broad range impact" scenario corresponded to the "Extended impact" scenario to where we extended the "halo effect" to drivers in the BAC category "0.8 g/L ≤ BAC < 1.2 g/L".

METHODS

The effect estimates were based on firstly, scientific literature on risks related to drink-driving at different BAC-levels, secondly data on crashes in Belgium and thirdly data on drink-driving behaviour in Belgium and in other European countries.

RESULTS

In case of a zero limit for all drivers, an annual reduction can be expected of 10 to 17 fatalities (i.e., a decrease of 2.4% to 3.9%), 8 to 20 severe injuries (i.e., a decrease of 0.3% to 0.8%) and 135 to 315 slight injuries (i.e., a decrease of 0.4% to 0.8%). In case a zero limit is only applied to novice drivers, an annual decrease can be expected by 2 to 4 fatalities (i.e., a decline of 3.7% to 6.2%), 8 to 16 serious injuries and 135 to 262 slight injuries (i.e., a decline of 1.7% to 3.2% in both cases).

DISCUSSION

There is no clear evidence on which of the three scenarios would be the most plausible. As the relative risk of a car crash increases strongly with the BAC level, the success of either measure will strongly depend on its ability to also affect drink driving at concentrations that are forbidden already. This also means that most of the casualties could be prevented if compliance with current rules increased.

Alcohol and Alcohol Combined with Texting: Evaluation of Driving Impairment Effects in a Closed-Course Section

OBJECTIVE

Examine the driving impairment effects of alcohol alone and of alcohol combined with texting.

METHODS

Fifteen drivers (nine male, six female; mean age: 31.1 ± 6.9 years, range: 23 to 43 years) with similar drinking habit (i.e., social drinkers) completed a lap in a closed-course section in six different situations: (I) sober; (II) sober and while texting; (III) 30 minutes after ingesting a moderate dose of ethanol (0.50 g/kg); (IV) 30 minutes after drinking and while texting; (V) 60 minutes after drinking, (VI) 60 minutes after drinking and while texting. Driving performance was analyzed by means of maximum and mean speed, braking time and braking distance; and ability to control the car (i.e., evaluating if the drivers hit a traffic cone or exceeded the boundaries of the course). P values of < 0.05 were considered significant.

RESULTS

Pre and post-alcohol consumption results show a significant increase concerning the drivers' mean and maximum speed after drinking (p < 3.2x10^-8). However, neither alcohol nor texting had significant effects on braking parameters (p > 0.05). Traffic cones were knocked down only in texting experiments. In addition, when using the cell phone drivers tended to reduce the speed, and to accelerate abruptly right after they finish texting.

CONCLUSION

Our findings strengthen the hypothesis that even moderate alcohol doses may significantly impair the driving performance. Additionally, alcohol and texting have complementary effects on driving impairment, and their combination represents a significant risk factor for crashes.

Combining ecstasy and ethanol: higher risk for toxicity? A review

Ecstasy use is commonly combined with ethanol consumption. While combination drug use in general is correlated with a higher risk for toxicity, the risk of the specific combination of ecstasy (3,4-methylenedioxymethamphetamine (MDMA)) and ethanol is largely unknown. Therefore, we have reviewed the literature on changes in MDMA pharmacokinetics and pharmacodynamics due to concurrent ethanol exposure in human, animal and in vitro studies. MDMA pharmacokinetics appear unaffected: the MDMA blood concentration after concurrent exposure to MDMA and ethanol was comparable to lone MDMA exposure in multiple human placebo-controlled studies. In contrast, MDMA pharmacodynamics were affected: locomotor activity increased and body temperature decreased after concurrent exposure to MDMA and ethanol compared to lone MDMA exposure. Importantly, these additional ethanol effects were consistently observed in multiple animal studies. Additional ethanol effects have also been reported on other pharmacodynamic aspects, but are inconclusive due to a low number of studies or due to inconsistent findings. These investigated pharmacodynamic aspects include monoamine brain concentrations, neurological (psychomotor function, memory, anxiety, reinforcing properties), cardiovascular, liver and endocrine effects. Although only a single or a few studies were available investigating these aspects, most studies indicated an aggravation of MDMA-induced effects upon concurrent ethanol exposure. In summary, concurrent ethanol exposure appears to increase the risk for MDMA toxicity. Increased toxicity is due to an aggravation of MDMA pharmacodynamics, while MDMA pharmacokinetics is largely unaffected. Although a significant attenuation of the MDMA-induced increase of body temperature was observed in animal studies, its relevance for human exposure remains unclear.

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.

Alcohol-impaired driving in rural and urban road environments: Effect on speeding behaviour and crash probabilities

Speeding behaviour is known to influence crash risk among alcohol-impaired drivers, but this relationship is scarcely explored. The present study investigated the effects of different Blood Alcohol Concentrations (BAC) levels on driving performance with respect to mean speed of drivers and their ability to avoid crashes during sudden events while driving. Eighty-two drivers participated in the simulation driving experiment at four BAC levels (0%, 0.03 %, 0.05 % and 0.08 % BAC) in rural and urban driving scenarios. Two sudden events (pedestrian crossing and road crossing by parked vehicles (a car and a truck) in the perpendicular direction of traffic) were designed to evaluate the crash probabilities in both the driving scenarios. Generalized linear mixed models were developed to analyse the effects of BAC levels and driver attributes (e.g., age, gender) on mean speeds and crash probabilities. Results for mean speed showed that, compared to sober state, drivers drove 3.5 kmph, 5.76 kmph and 8.78 kmph faster at 0.03 %, 0.05 % and 0.08 % BAC respectively in the rural environment and this increment was 3.6 kmph, 3.69 kmph and 4.13 kmph in the urban environment. The model results for crash probabilities revealed that 0.03 %, 0.05 % and 0.08 % BAC levels increased the crash probabilities by 1.9 times, 2 times and 3 times in case of the rural environment and 2 times, 2.3 times and 3.5 times respectively in the urban driving environment.

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.

Evaluation of simulated driving in comparison to laboratory-based tests to assess the pharmacodynamics of alprazolam and alcohol

RATIONALE

Assessment of the effects of medicines on the risks of car driving must be derived from laboratory tests, simulated driving or real on-road driving tests. Relevance of tests is determined by their sensitivity and predictive ability for the probability of accidents or damage. This cannot be determined directly, but methods should be able to at least detect the effects of a positive control in dosage known to be clearly associated with increased risk.

OBJECTIVES

A driving simulator was evaluated in comparison with a battery of validated tests of CNS performance, the NeuroCart®. Alcohol in a concentration exactly at the legal limit (0.5 g L^-1) and well above (1.0 g L^-1) as well as alprazolam (1 mg) was used as positive control.

METHODS

This was a randomised, cross-over study using a double dummy blinded design in 24 healthy study subjects (12 M, 12 F) aged 20-43 years. Alcohol was infused intravenously using a validated clamping protocol to obtain concentrations of 0.5 g L^-1 and on another occasion 1.0 g L^-1. Alprazolam was given orally. Driving tests and lab tests were done at regular time intervals during a study day.

RESULTS

Alprazolam and alcohol significantly affected the main parameters of driving in the simulator and affected scores of safe driving and alprazolam increased the odds ratio of a virtual crash. Several laboratory measurements of psychomotor performance were affected by the reference substances as expected and correlated significantly with the driving performance.

CONCLUSIONS

The driving simulator can detect effects of reference substances at levels that are known to negatively affect driving.

Conversion factors for assessment of driving impairment after exposure to multiple benzodiazepines/z-hypnotics or opioids

AIMS

Norway has introduced legal concentration limits in blood for 28 non-alcohol drugs in driving under the influence cases. As of 2016 this legislation also regulates the assessment of combined effects of multiple benzodiazepines and opioids. We herein describe the employed methodology for the equivalence tables for concentrations of benzodiazepines/z-hypnotics and opioids implemented in the Norwegian Road Traffic Act.

METHODS

Legislative limits corresponding to impairment at blood alcohol concentrations (BAC) of 0.02%, 0.05% and 0.12% were established for 15 different benzodiazepines and opioids. This was based on a concept of a linear relationship between blood drug concentration and impairment in drug naïve users. Concentration ratios between these drugs were used to establish conversion factors and calculate net impairment using diazepam and morphine equivalents.

RESULTS

Conversion factors were established for 14 benzodiazepines/z-hypnotics (alprazolam, bromazepam, clobazam, clonazepam, etizolam, flunitrazepam, lorazepam, nitrazepam, nordiazepam, oxazepam, phenazepam, temazepam, zolpidem and zopiclone) and two opioids (methadone and oxycodone).

CONCLUSIONS

Conversion factors to calculate diazepam and morphine equivalents for benzodiazepines/z-hypnotics and selected opioids, respectively, have been operative in the Norwegian Road Traffic Act as of February 2016. Calculated equivalents can be applied by the courts to meter out sanctions.

The influence of groups and alcohol consumption on individual risk-taking

BACKGROUND

Research addressing the influence of alcohol and groups on risky behaviour has yielded contradictory findings regarding the extent to which intoxicated groups exaggerate or minimise risk-taking. Previous work has examined the effect of intoxication on risk-taking focusing on collective group decision-making, and to date the influence of alcohol consumption and groups on individual risk-taking has yet to be explored experimentally. The current study therefore examined the impact of intoxication and groups on individual risk-taking.

METHODS

In a mixed design, 99 social drinkers (62 female) attended an experimental session individually (N=48) or in groups of three (N=51). Individuals completed the study in isolation while groups were tested in the same room. Participants completed two behavioural measures of risk-taking: Balloon Analogue Risk Task (BART) and Stoplight Task (SLT), both before and following consumption of an alcoholic (0.6g/kg males, 0.5g/kg females) or a placebo beverage.

RESULTS

Those who participated in groups took significantly more risks in both tasks than those in isolation. Alcohol did not increase risk-taking on either risk-taking tasks. However, those who consumed placebo were significantly less risky on the SLT, compared to baseline. No interactions were found between context and beverage on risk-taking.

CONCLUSION

The findings do not support a combined effect of alcohol and groups on individual risk-taking. Rather, results indicate that risk-taking behaviour is influenced by peer presence regardless of alcohol consumption. Targeting the influence of groups (above those of alcohol) may hold promise for reducing risk-taking behaviours in drinking environments.

Drinking and driving behavior at stop signs and red lights

Alcohol is one of the principal risk factors for motor vehicle crashes. One factor that contributes to vehicle crashes is noncompliance with stop signs and red lights. The present experiment investigated the effects of alcohol and drinking patterns on driving behavior at stop signs and red lights. 28 participants participated in drinking and simulated driving sessions during which they received a moderate dose of alcohol (0.08% BAC) or a placebo. Simulated driving tasks measured participants' driving performance at stop signs and red lights in response to each dose. Results suggested that alcohol impaired the driver control of speed and direction and prolonged their simple and complex reaction time, which were exhibited by impaired speed and lateral control, longer reaction time when the lights turned yellow, and lower deceleration towards stop signs and red lights. Visual degradation may also occur under alcohol intake. It was also suggested that alcohol impaired non-binge drinkers more severely. To be specific, higher acceleration was observed in impaired non-binge drinkers.

Alcohol consumption for simulated driving performance: A systematic review

PURPOSE

Alcohol consumption can lead to risky driving and increase the frequency of traffic accidents, injuries and mortalities. The main purpose of our study was to compare simulated driving performance between two groups of drivers, one consumed alcohol and the other not consumed, using a systematic review.

METHODS

In this systematic review, electronic resources and databases including Medline via Ovid SP, EMBASE via Ovid SP, PsycINFO via Ovid SP, PubMed, Scopus, Cumulative Index to Nursing and Allied Health Literature (CINHAL) via EBSCOhost were comprehensively and systematically searched. The randomized controlled clinical trials that compared simulated driving performance between two groups of drivers, one consumed alcohol and the other not consumed, were included. Lane position standard deviation (LPSD), mean of lane position deviation (MLPD), speed, mean of speed deviation (MSD), standard deviation of speed deviation (SDSD), number of accidents (NA) and line crossing (LC) were considered as the main parameters evaluating outcomes. After title and abstract screening, the articles were enrolled for data extraction and they were evaluated for risk of biases.

RESULTS

Thirteen papers were included in our qualitative synthesis. All included papers were classified as high risk of biases. Alcohol consumption mostly deteriorated the following performance outcomes in descending order: SDSD, LPSD, speed, MLPD, LC and NA. Our systematic review had troublesome heterogeneity.

CONCLUSION

Alcohol consumption may decrease simulated driving performance in alcohol consumed people compared with non-alcohol consumed people via changes in SDSD, LPSD, speed, MLPD, LC and NA. More well-designed randomized controlled clinical trials are recommended.

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).

Investigating risky, distracting, and protective peer passenger effects in a dual process framework

Prior studies indicated higher collision rates among young novice drivers with peer passengers. This driving simulator study provided a test for a dual process theory of risky driving by examining social rewards (peer passengers) and cognitive control (inhibitory control). The analyses included age (17-18 yrs, n=30; 21-24 yrs, n=20). Risky, distracting, and protective effects were classified by underlying driver error mechanisms. In the first drive, participants drove alone. In the second, participants drove with a peer passenger. Red-light running (violation) was more prevalent in the presence of peer passengers, which provided initial support for a dual process theory of risk driving. In a subgroup with low inhibitory control, speeding (violation) was more prevalent in the presence of peer passengers. Reduced lane-keeping variability reflected distracting effects. Nevertheless, possible protective effects for amber-light running and hazard handling (cognition and decision-making) were found in the drive with peer passengers. Avenues for further research and possible implications for targets of future driver training programs are discussed.

The sensitivity of laboratory tests assessing driving related skills to dose-related impairment of alcohol: A literature review

Laboratory tests assessing driving related skills can be useful as initial screening tools to assess potential drug induced impairment as part of a standardized behavioural assessment. Unfortunately, consensus about which laboratory tests should be included to reliably assess drug induced impairment has not yet been reached. The aim of the present review was to evaluate the sensitivity of laboratory tests to the dose dependent effects of alcohol, as a benchmark, on performance parameters. In total, 179 experimental studies were included. Results show that a cued go/no-go task and a divided attention test with primary tracking and secondary visual search were consistently sensitive to the impairing effects at medium and high blood alcohol concentrations. Driving performance assessed in a simulator was less sensitive to the effects of alcohol as compared to naturalistic, on-the-road driving. In conclusion, replicating results of several potentially useful tests and their predictive validity of actual driving impairment should deserve further research. In addition, driving simulators should be validated and compared head to head to naturalistic driving in order to increase construct validity.

The odds of wrong-way crashes and resulting fatalities: A comprehensive analysis

The United States of America and other nations are grappling with the incidence of wrong-way driving (WWD). The issue is as important today (NTSB, 2012) as it was a half-century ago (Hulbert and Beers, 1966). In the absence of a comprehensive analysis, any effort to implement WWD countermeasures can be counterproductive. Hence, this effort began with the express intent to identify the factors that cause WWD crashes and fatalities. This work is sizeable in that it evaluated one million complete crash records from Florida. The methodology comprised (a) administering a survey on the perceptions about WWD; (b) developing binomial logistic models for computing the odds of WWD crashes, and of fatal crashes within the WWD space; (c) analyzing the contributing variables; and (d) comparing perceptions with crash analysis results. The study parameters included driver's age, gender, licensing state, physical defect, blood alcohol concentration, vehicle use, seatbelt compliance, day and time of crash, roadway lighting, facility type, weather conditions, road geometrics, and traffic volumes. Individual variable analysis of 23 parameters and the model development process included the determination of odds ratios and statistical tests for the predictive power and goodness-of-fit. The results of this work are generally consistent with expectation, yet surprising at times. This work concludes with decision-making inputs to the scientist, policy-maker and practitioner on the need for effectively engineering the roads, actively educating people about wrong-way driving, and strictly enforcing traffic laws, rules and regulations.

Comparing treatment effects of oral THC on simulated and on-the-road driving performance: testing the validity of driving simulator drug research

RATIONALE

The driving simulator provides a safe and controlled environment for testing driving behaviour efficiently. The question is whether it is sensitive to detect drug-induced effects.

OBJECTIVE

The primary aim of the current study was to investigate the sensitivity of the driving simulator for detecting drug effects. As a case in point, we investigated the dose-related effects of oral ∆(9)-tetrahydrocannabinol (THC), i.e. dronabinol, on simulator and on-the-road driving performance in equally demanding driving tasks.

METHOD

Twenty-four experienced driver participants were treated with dronabinol (Marinol®; 10 and 20 mg) and placebo. Dose-related effects of the drug on the ability to keep a vehicle in lane (weaving) and to follow the speed changes of a lead car (car following) were compared within subjects for on-the-road versus in-simulator driving. Additionally, the outcomes of equivalence testing to alcohol-induced effects were investigated.

RESULTS

Treatment effects found on weaving when driving in the simulator were comparable to treatment effects found when driving on the road. The effect after 10 mg dronabinol was however less strong in the simulator than on the road and inter-individual variance seemed higher in the simulator. There was, however, a differential treatment effect of dronabinol on reactions to speed changes of a lead car (car following) when driving on the road versus when driving in the simulator.

CONCLUSION

The driving simulator was proven to be sensitive for demonstrating dronabinol-induced effects particularly at higher doses. Treatment effects of dronabinol on weaving were comparable with driving on the road but inter-individual variability seemed higher in the simulator than on the road which may have potential effects on the clinical inferences made from simulator driving. Car following on the road and in the simulator were, however, not comparable.

A neuropsychological instrument measuring age-related cerebral decline in older drivers: development, reliability, and validity of MedDrive

When facing age-related cerebral decline, older adults are unequally affected by cognitive impairment without us knowing why. To explore underlying mechanisms and find possible solutions to maintain life-space mobility, there is a need for a standardized behavioral test that relates to behaviors in natural environments. The aim of the project described in this paper was therefore to provide a free, reliable, transparent, computer-based instrument capable of detecting age-related changes on visual processing and cortical functions for the purposes of research into human behavior in computational transportation science. After obtaining content validity, exploring psychometric properties of the developed tasks, we derived (Study 1) the scoring method for measuring cerebral decline on 106 older drivers aged ≥70 years attending a driving refresher course organized by the Swiss Automobile Association to test the instrument's validity against on-road driving performance (106 older drivers). We then validated the derived method on a new sample of 182 drivers (Study 2). We then measured the instrument's reliability having 17 healthy, young volunteers repeat all tests included in the instrument five times (Study 3) and explored the instrument's psychophysical underlying functions on 47 older drivers (Study 4). Finally, we tested the instrument's responsiveness to alcohol and effects on performance on a driving simulator in a randomized, double-blinded, placebo, crossover, dose-response, validation trial including 20 healthy, young volunteers (Study 5). The developed instrument revealed good psychometric properties related to processing speed. It was reliable (ICC = 0.853) and showed reasonable association to driving performance (R (2) = 0.053), and responded to blood alcohol concentrations of 0.5 g/L (p = 0.008). Our results suggest that MedDrive is capable of detecting age-related changes that affect processing speed. These changes nevertheless do not necessarily affect driving behavior.

The effects of moderate alcohol concentrations on driving and cognitive performance during ascending and descending blood alcohol concentrations

OBJECTIVE

Alcohol has an adverse effect on driving performance; however, the effects of moderate doses on different aspects of the driving task are inconsistent and differ across the intoxication curve. This research aimed to investigate driving and cognitive performance asymmetries (acute tolerance and acute protracted error) accompanying the onset and recovery from moderate alcohol consumption.

METHODS

Sixty-one participants received a placebo, medium (target blood alcohol concentration [BAC] 0.05 mg/ml) or high (target BAC 0.08 mg/ml) dose of alcohol. Participants completed a simulated drive, cognitive tests and subjective rating scales five times over a 3.5 h period.

RESULTS

When ascending and descending BACs (0.05 and 0.09 mg/ml) were compared participants' self-ratings of intoxication and willingness to drive showed acute tolerance. Acute protracted errors were observed for response speed, maze learning errors, time exceeding the speed limit and exaggerated steering responses to hazards.

CONCLUSIONS

Participants' estimates of their level of intoxication were poorly related to their actual BAC levels (and hence degree of impairment), and various aspects of driving and cognitive performance worsened during descending BACs. This indicates that drivers are not good at judging their fitness to drive after drinking only moderate amounts of alcohol and suggests an important focus for public education regarding alcohol and driving.

Effects of alcohol on automated and controlled driving performances

RATIONALE

Alcohol is the most frequently detected substance in fatal automobile crashes, but its precise mode of action is not always clear.

OBJECTIVE

The present study was designed to establish the influence of blood alcohol concentration as a function of the complexity of the scenarios. Road scenarios implying automatic or controlled driving performances were manipulated in order to identify which behavioral parameters were deteriorated.

METHOD

A single blind counterbalanced experiment was conducted on a driving simulator. Sixteen experienced drivers (25.3 ± 2.9 years old, 8 men and 8 women) were tested with 0, 0.3, 0.5, and 0.8 g/l of alcohol. Driving scenarios varied: road tracking, car following, and an urban scenario including events inspired by real accidents. Statistical analyses were performed on driving parameters as a function of alcohol level.

RESULTS

Automated driving parameters such as standard deviation of lateral position measured with the road tracking and car following scenarios were impaired by alcohol, notably with the highest dose. More controlled parameters such as response time to braking and number of crashes when confronted with specific events (urban scenario) were less affected by the alcohol level.

CONCLUSION

Performance decrement was greater with driving scenarios involving automated processes than with scenarios involving controlled processes.

A review of alcohol-impaired driving: the role of blood alcohol concentration and complexity of the driving task

The operation of a motor vehicle requires the integrity of sensory, motor, and intellectual faculties. Impairment of these faculties following the consumption of alcohol has been studied extensively through laboratory, closed-course and on-road driving, and epidemiological studies. The scientific literature was reviewed critically, with a focus on low-to-moderate blood alcohol concentrations (BAC ≤ 0.100%), to identify the most reliable determinants of alcohol-impaired driving. Variables such as age, gender, driving skill, and tolerance were shown to have limited impact on impairment. It was concluded the most relevant variables are BAC and complexity of the driving task. The scientific literature provides a high degree of confidence to support the conclusion that a BAC of 0.050% impairs faculties required in the operation of a motor vehicle. Whether impairment is apparent depends upon the complexity of the driving task, which applies to both study design and actual driving.

Effects of three therapeutic doses of codeine/paracetamol on driving performance, a psychomotor vigilance test, and subjective feelings

RATIONALE

Some recent pharmacoepidemiological studies revealed an elevated risk of driving accidents after opioid analgesics uses. Among analgesics, codeine is often associated with paracetamol in numerous pharmaceutical specialties.

OBJECTIVES

The objective of this study was to evaluate the dose-effect relationship of three usual therapeutic doses of codeine/paracetamol on driving ability, psychomotor performance, subjective alertness, in link with blood concentrations in healthy young volunteers.

METHODS

Driving performance, responses to psychomotor vigilance tests, and scales reflecting alertness were evaluated during the morning after drug intake in a double-blind, randomized, placebo-controlled study. Sixteen healthy volunteers (23.4 ± 2.7 years old, 8 men and 8 women) participated in this balanced, cross-over study. Three doses of codeine/paracetamol (20/400, 40/800, 60/1200 mg) were evaluated against placebo. Two blood samples were collected, 1 and 4 h after drug intake. In serum, codeine and morphine concentrations were determined in serum using high-performance liquid chromatography electrospray ionization-tandem mass spectrometry, and paracetamol concentrations using fluorescence polarization immunoassay.

RESULTS

Driving and psychomotor performance were not affected by any of the three codeine/paracetamol doses. However, significant, though modest, correlations were observed between the driving parameters and both morphine and codeine blood concentrations.

CONCLUSIONS

This study did not reveal any significant impairment in performance due to the three therapeutic doses used in healthy young volunteers. However, the relationships between drug blood concentration and behavioral measures suggest that an inter-subject variability in blood concentration may influence the power of the observed drug effect.