When does alcohol hurt? A driving simulator study

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.

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.

Modelling brake transition time of young alcohol-impaired drivers using hazard-based duration models

Braking performance of drivers is a crucial factor in evaluating the collision patterns and implementing road safety measures. Further, alcohol is known to impair driving control. The present study aims to examine the influence of a comprehensive range of Blood Alcohol Concentration (BAC) levels (0%, 0.03 %, 0.05 % and 0.08 %) on brake transition times of drivers. As young drivers show significantly higher crash risks compared to the experienced drivers, fifty-four young Indian drivers in the age group of 21-25 years (forty males and fourteen females) participated in the driving simulator experiments. The study adopted the framework of a within-subjects design, where each driver encountered rural and urban driving scenarios in a counterbalanced order, during experimental driving at each of the four BAC levels. Their brake transition times were estimated with respect to sudden pedestrian crossing events. Weibull Accelerated Failure Time (AFT) models with shared frailty were developed for quantifying the effects of BAC levels along with driver attributes on brake transition time. Preliminary analysis showed significant main effects of BAC (p < 0.001) and driving environment (p = 0.002) on brake transition time; however, their interaction effect was not significant (p = 0.485). The models revealed that 0.03 %, 0.05 % and 0.08 % BACs significantly reduced the brake transition times by 16 %, 28 % and 52 % in rural driving environment, and by 23 %, 37 % and 53 % in urban driving environment, compared to 0% BAC. The study outcomes may find application in assisting collision warning systems which take into account the braking behaviour of drivers.

Applications of brain imaging methods in driving behaviour research

Applications of neuroimaging methods have substantially contributed to the scientific understanding of human factors during driving by providing a deeper insight into the neuro-cognitive aspects of driver brain. This has been achieved by conducting simulated (and occasionally, field) driving experiments while collecting driver brain signals of various types. Here, this sector of studies is comprehensively reviewed at both macro and micro scales. At the macro scale, bibliometric aspects of these studies are analysed. At the micro scale, different themes of neuroimaging driving behaviour research are identified and the findings within each theme are synthesised. The surveyed literature has reported on applications of four major brain imaging methods. These include Functional Magnetic Resonance Imaging (fMRI), Electroencephalography (EEG), Functional Near-Infrared Spectroscopy (fNIRS) and Magnetoencephalography (MEG), with the first two being the most common methods in this domain. While collecting driver fMRI signal has been particularly instrumental in studying neural correlates of intoxicated driving (e.g. alcohol or cannabis) or distracted driving, the EEG method has been predominantly utilised in relation to the efforts aiming at development of automatic fatigue/drowsiness detection systems, a topic to which the literature on neuro-ergonomics of driving particularly has shown a spike of interest within the last few years. The survey also reveals that topics such as driver brain activity in semi-automated settings or neural activity of drivers with brain injuries or chronic neurological conditions have by contrast been investigated to a very limited extent. Potential topics in driving behaviour research are identified that could benefit from the adoption of neuroimaging methods in future studies. In terms of practicality, while fMRI and MEG experiments have proven rather invasive and technologically challenging for adoption in driving behaviour research, EEG and fNIRS applications have been more diverse. They have even been tested beyond simulated driving settings, in field driving experiments. Advantages and limitations of each of these four neuroimaging methods in the context of driving behaviour experiments are outlined in the paper.

Deterioration of binocular vision after alcohol intake influences driving performance

In this study, we assessed the influence of moderate alcohol intake on binocular vision, vergence system and simulated driving performance by analyzing the interactions between visual deterioration and driving variables. Thirty young healthy subjects were recruited. For the analysis, we measured: visual function (visual acuity and stereoacuity), phorias and fusional reserves. Also, we checked Sheard's and Percival's criteria at near and far. The accommodative convergence/accommodation (AC/A) ratio was calculated and vergence facility was also obtained at near. A driving simulator was used to assess driving performance under natural conditions and after alcohol consumption with a breath alcohol content of 0.40 mg/l. Alcohol intake significantly reduced binocular visual performance and vergence function, except for vertical phorias, horizontal phoria at near and Sheard's and Percival's criteria at near. Driving performance parameters also presented a statistically significant deterioration after alcohol consumption. A statistically significant correlation was found between the deterioration in overall visual function and overall driving performance, highlighting the influence of the visual deterioration on the driving performance. Moderate alcohol consumption impairs binocular visual and simulated driving performances, implying a greater safety hazard. In addition, deteriorations in binocular visual function and vergence correlated with simulated driving impairment, which indicates that the deterioration of binocular vision due to alcohol consumption affects driving, thus reducing road safety.

Optical pavement treatments and their impact on speed and lateral position at transition zones: A driving simulator study

Transition zones are a road section where posted speed drops from higher to lower limits. Due to the sudden changes in posted speed limits and road environment, drivers usually do not adapt to the posted speed limits and underestimate their traveling speed. Previous studies have highlighted that crash rates are usually higher in these sections. This study aims at improving the safety at transition zones by introducing perceptual measures that are tested using a driving simulator. The proposed measures are speed limit pavement markings with a gradual increase of brightness and/or size that were placed at transition zones in simulation scenarios replicating the real-world environment of the Doha Expressway in Qatar. These innovative measures aim to produce the impression of increased speed that could stimulate drivers to better adapt speed limits. The driving behavior of 81 drivers possessing a valid Qatari driving license was recorded with a driving simulator interfaced with STISIM Drive® 3. Results showed that pavement markings combining size and brightness manipulations were the most effective treatment, keeping drivers' traveling speed significantly below the traveling speed recorded in the untreated control condition. In this regard, the maximum mean speed reductions of 5.3 km/h and 4.6 km/h were observed for this treatment at the first transition (120 to 100 km/h) and second transition (100 to 80 km/h) zones, respectively. Regarding the variations in drivers' lateral position, the results showed that the proposed pavement markings did not negatively influence drivers' lateral control on the road as the maximum observed standard deviation of lateral position was around 0.065 m. This study shows that the proposed pavement markings are recommended for improving the speed adaptation of drivers in the transition zones.

Contrast sensitivity and retinal straylight after alcohol consumption: effects on driving performance

In this study, we aimed to investigate the effects of alcohol intake on visual function and driving performance, as well as on the relationship between these. A total of 40 healthy participants took part in three experimental sessions: one baseline session and two further sessions after consuming two different quantities of alcohol (300 ml and 450 ml of red wine). The breath alcohol content (BrAC) was measured using a breath analyzer. The contrast sensitivity and retinal straylight due to the forward intraocular scattering were measured to characterize visual function, and driving performance was assessed in three different scenarios using a driving simulator. The results showed a deterioration in contrast sensitivity and retinal straylight after drinking alcohol, in addition to an impaired ability to drive, especially for the highest alcohol intake. We also observed that the deteriorated driving performance was a function of the contrast sensitivity and retinal straylight under the effects of alcohol, indicating that these visual variables can partially predict driving performance in these conditions.

Effects of Different Alcohol Dosages on Steering Behavior in Curve Driving

OBJECTIVE

The aim of this article is to explore the detailed characteristics of steering behavior in curve driving at different alcohol dosages.

BACKGROUND

Improper operation of the steering wheel is a contributing factor to increased crash risks on curves.

METHOD

The experiments were conducted using a driving simulator. Twenty-five licensed drivers were recruited to perform the experiments at the four different breath alcohol concentration (BrAC) levels. The steering angle (SA), steering speed (SS), steering reversal rate (SRR), and peak-to-peak value of the steering angle (PP) were used to characterize the steering behavior. The vehicle's speed and the number of lane exceedances per kilometer were also used to examine the driving performance.

RESULTS

The SSs on the 200 m (χ²(3) = 20.67, p < .001), 500 m (χ²(3) = 22.42, p < .001), and 800 m (χ²(3) = 22.86, p < .001) radius curves were significantly faster for drivers under the influence of alcohol compared with those given a placebo. There were significant effects of alcohol on the SRR and PP on the 200 m, 500 m, and 800 m radius curves.

CONCLUSION

For all of the curves, the SS, SRR, and PP had a tendency to increase as the BrAC increased. The large PP at a high BrAC, accompanied by the high speed, SS, and SRR, resulted in a high probability of lane exceedance. The use of measures of SS, SRR, and PP aided in the improvement of the accuracy of the intoxication detection for the different types of curves.

APPLICATION

The most important application is to provide guidance for detecting alcohol-impaired-driving.