Effects of prolonged wakefulness combined with alcohol and hands-free cell phone divided attention tasks on simulated driving

Enhancement of unsafe behaviors in simulated moped-riding performance under the influence of low dose of alcohol

The effects of low levels of blood alcohol concentration (BAC) on motorcyclist performance are still not fully comprehended. The great majority of the studies are, in fact, focused on car driving. So far, it is known that even BAC levels below the legal limit negatively affect riding motor skills correlated with crash rate. In the present study, we used a moped riding simulator to investigate the effects of low alcohol dosages (under the limits established in Italy, and in most European countries) on the defensive riding ability of light drinkers, particularly focusing on the degree of danger characterizing their riding performance. We recruited 24 participants through a double-blind, random distribution, balanced, cross-over design. We administered moderate amounts of alcohol to participants during two sessions of moped riding simulation. The results showed that even though BAC levels were always below (mean value: 0.03 g/dL) the limit allowed by Italian traffic law (0.05 g/dL), alcohol induced a reduction in safe riding behaviors, as indicated by the greater amount of hazardous scenes faced with dangerous riding behaviors when participants were under the influence of alcohol than when they were sober. Moreover, low BAC levels had a greater detrimental influence when a certain amount of learning had already been achieved by the participants (i.e., in the last experimental session). The results suggest that the effect of a low dose of alcohol interacts with participants' self-confidence.

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.

A comparison of the effect of mobile phone use and alcohol consumption on driving simulation performance

OBJECTIVE

The present study compared the effects of a variety of mobile phone usage conditions to different levels of alcohol intoxication on simulated driving performance and psychomotor vigilance.

METHODS

Twelve healthy volunteers participated in a crossover design in which each participant completed a simulated driving task on 2 days, separated by a 1-week washout period. On the mobile phone day, participants performed the simulated driving task under each of 4 conditions: no phone usage, a hands-free naturalistic conversation, a hands-free cognitively demanding conversation, and texting. On the alcohol day, participants performed the simulated driving task at four different blood alcohol concentration (BAC) levels: 0.00, 0.04, 0.07, and 0.10. Driving performance was assessed by variables including time within target speed range, time spent speeding, braking reaction time, speed deviation, and lateral lane position deviation.

RESULTS

In the BAC 0.07 and 0.10 alcohol conditions, participants spent less time in the target speed range and more time speeding and took longer to brake in the BAC 0.04, 0.07, and 0.10 than in the BAC 0.00 condition. In the mobile phone condition, participants took longer to brake in the natural hands-free conversation, cognitively demanding hands-free conversation and texting conditions and spent less time in the target speed range and more time speeding in the cognitively demanding, hands-free conversation, and texting conditions. When comparing the 2 conditions, the naturalistic conversation was comparable to the legally permissible BAC level (0.04), and the cognitively demanding and texting conversations were similar to the BAC 0.07 to 0.10 results.

CONCLUSION

The findings of the current laboratory study suggest that very simple conversations on a mobile phone may not represent a significant driving risk (compared to legally permissible BAC levels), whereas cognitively demanding, hands-free conversation, and particularly texting represent significant risks to driving.

Effects of Alzheimer's disease and mild cognitive impairment on driving ability: a controlled clinical study by simulated driving test

OBJECTIVE

To assess the effects of Alzheimer's disease (AD) and Mild Cognitive Impairment (MCI) on simulated car driving ability.

METHODS

Twenty patients with a probable AD of mild severity (Clinical Dementia Rating, CDR = 1) were compared with 20 subjects with MCI (CD = 0.5), and a group of age-matched neurologically normal controls on a driving simulation task. Measures of driving competence included the length of run, the number of infractions (omission of stop at pedestrian crossings, speed limits violation), the number of stops at traffic lights, the mean time to collision, and the number of off-road events. Results in the driving competence measures were correlated with scores obtained from simple visual reaction times and mini-mental state examination (MMSE).

RESULTS

The patients with mild AD performed significantly worse than MCI subjects and controls on three simulated driving measures, length of run and mean time to collision (p < 0.001), and number of off-road events (p < 0.01). MCI subjects had only a significantly shorter time-to-collision than healthy controls (p < 0.001). Simple visual reaction times were significantly longer (p < 0.001) in patients with AD, compared to MCI and healthy controls, and showed a borderline significant relation (p = 0.05) with simulated driving scores. Driving performance in the three groups did not significantly correlate with MMSE score as measure of overall cognitive function.

CONCLUSIONS

Mild AD significantly impaired simulated driving fitness, while MCI limitedly affected driving performance. Unsafe driving behaviour in AD patients was not predicted by MMSE scores.

Effect of driver distraction and low alcohol concentrations on useful field of view and frequency-doubling technology perimetry

PURPOSE

To investigate the effects of a mental psychometric task that simulates the distraction effect of a hands-free mobile phone and of low alcohol concentrations (0.3-0.5 g/l) on two tests: the useful field of view (UFOV) and frequency-doubling technology (FDT) perimetry.

METHODS

Thirty-seven healthy young vehicle drivers aged 22 +/- 3 years were subjected to a computer version of the UFOV test and FDT perimetry, undertaken according to a counterbalanced within-subject design. The tests were performed in two sessions (an 'alcohol session' and a 'sober session'), while undertaking or not undertaking a psychometric test [the Paced Auditory Serial Addition Test (PASAT)] to simulate the effect of distraction. Each subject was instructed to concentrate on the PASAT while taking each test.

RESULTS

UFOV scores were affected when the PASAT was performed simultaneously (P < 0.0001) in that longer times were required to identify a central target and the location of a peripheral target. FDT perimetry was affected by the addition of the PASAT, with a significant reduction in mean sensitivity and a localized sensitivity loss [pattern standard deviation (PSD) >6 dB]. Test times, false-positive and negative catch trial responses were all increased. However, the UFOV test and FDT perimetry results were not significantly affected by a low alcohol concentration.

CONCLUSION

Distraction significantly affects performance in the UFOV test and frequency-doubling technology perimetry. Our findings suggest that using a hands-free mobile phone while driving may lead to a low-to-moderate crash risk in young adults with normal visual function.

Combined effects of alcohol and distraction on driving performance

Although alcohol and distraction are often cited as significant risk factors for traffic crashes, most research has considered them in isolation. It is therefore necessary to consider the interactions between alcohol and distraction impairment sources, especially when examining the relationship between behavior and crash risk. In a driving simulator, the primary goal was to maintain a safe headway to a lead vehicle and the secondary goal was to maintain stable lane position. All participants engaged in distractions that represented different levels of resource competition and half of the participants consumed alcohol (target BAC 0.08 g/dl). Specific comparisons were made between sober driving while distracted and driving intoxicated without distraction. Distraction tasks produced more changes in driving behavior than did alcohol for both longitudinal (primary) and lateral (secondary) driving goals. Alcohol impairment was evident only in relation to lateral driving performance, however there was an amplification of impairment when alcohol and distraction conditions were combined. Distraction resulted in a general level of impairment across all driving goals, whereas participants with alcohol appeared to shed secondary driving goals to "protect" primary driving goals. Drivers' strategies to cope with alcohol (and distraction) may not be sufficient to offset the increased crash risk.