Drug and alcohol use among drivers admitted to a Level-1 trauma center

The purpose of this research was to determine the incidence and prevalence of drug use, alcohol use, and the combination of drug and alcohol use among motor vehicle crash (MVC) victims admitted to a Level-1 trauma center. In a 90-day study, nearly two-thirds of trauma center admissions were victims of motor vehicle crashes. Blood and urine was collected from 168 MVC victims of whom 108 were identified as the driver in the crash. Toxicology results indicated that 65.7% of drivers tested positive for either commonly abused drugs or alcohol. More than half of the drivers tested positive for drugs (50.9%) other than alcohol, with one in four drivers testing positive for marijuana use. About one-third of those using drugs had also been drinking, but alcohol was detected in only 30.6% of all injured drivers. Within the total MVC patient pool, passenger drug/alcohol use was equivalent to the driver population; however, injured pedestrians had higher rates of alcohol only than other MVC victims. There were no significant differences in drug and alcohol use between MVCs and trauma admissions of other causes. Of the patients with positive toxicology results, less than half (42%) were referred for evaluation for substance abuse disorders.     

Models of driving behavior: A review of their evolution

This paper reviews models that emphasize the cognitive components of driving behavior. Studies of individual differences have sought predictors of accident histories. Typically low correlations and reliance on post hoc explanations reflect theoretical deficiencies and problems with the use of accident measures. Motivational models emphasize transient, situation-specific factors rather than stable, individual predictors. However, neither testable hypotheses nor suitable methods have been developed to study situational factors and motives that influence driving. More recent models have incorporated a hierarchical control structure, which assumes concurrent activity at strategic, maneuvering, and operational levels of control. At the same time, automaticity has emerged as a central construct in cognitive psychology. All activities are assumed to combine fast, automatic components with slower, more deliberate, controlled processing. It is argued that identifying the situational factors that increase drivers' uncertainty and thus trigger a shift in attention from automatic to controlled processing will help integrate concepts of automaticity and motivational models. Finally, recent theorizing has suggested that errors associated with the inherent variability of human behavior may be more important to roadway crash causation than systematic errors, which are attributable to the known limits of the human information-processing system. Drivers' abilities to recover from errors may also be important to crash causation. It is concluded that the hierarchical control structure and theories of automaticity and errors provide the potential tools for defining alternative criterion measures, such as safety margins, and developing testable theories of driving behavior and crash causation. Two examples of models that integrate information-processing mechanisms within a motivational framework are described.     

The influence of combined alignments on lateral acceleration on mountainous freeways: a driving simulator study

Combined horizontal and vertical alignments are frequently used in mountainous freeways in China; however, design guidelines that consider the safety impact of combined alignments are not currently available. Past field studies have provided some data on the relationship between road alignment and safety, but the effects of differing combined alignments on either lateral acceleration or safety have not systematically examined. The primary reason for this void in past research is that most of the prior studies used observational methods that did not permit control of the key variables. A controlled parametric study is needed that examines lateral acceleration as drivers adjust their speeds across a range of combined horizontal and vertical alignments. Such a study was conducted in Tongji University’s eight-degree-of-freedom driving simulator by replicating the full range of combined alignments used on a mountainous freeway in China. Multiple linear regression models were developed to estimate the effects of the combined alignments on lateral acceleration. Based on these models, domains were calculated to illustrate the results and to assist engineers to design safer mountainous freeways.     

Does attention capacity moderate the effect of driver distraction in older drivers?

With age, a decline in attention capacity may occur and this may impact driving performance especially while distracted. Although the effect of distraction on driving performance of older drivers has been investigated, the moderating effect of attention capacity on driving performance during distraction has not been investigated yet. Therefore, the aim was to investigate whether attention capacity has a moderating effect on older drivers’ driving performance during visual distraction (experiment 1) and cognitive distraction (experiment 2). In a fixed-based driving simulator, older drivers completed a driving task without and with visual distraction (experiment 1, N = 17, mean age 78 years) or cognitive distraction (experiment 2, N = 35, mean age 76 years). Several specific driving measures of varying complexity (i.e., speed, lane keeping, following distance, braking behavior, and crashes) were investigated. In addition to these objective driving measures, subjective measures of workload and driving performance were also included. In experiment 1, crash occurrence increased with visual distraction and was negatively related to attention capacity. In experiment 2, complete stops at stop signs decreased, initiation of braking at pedestrian crossings was later, and crash occurrence increased with cognitive distraction. Interestingly, for a measure of lane keeping (i.e., standard deviation of lateral lane position (SDLP)), effects of both types of distraction were moderated by attention capacity. Despite the decrease of driving performance with distraction, participants estimated their driving performance during distraction as good. These results imply that attention capacity is important for driving. Driver assessment and training programs might therefore focus on attention capacity. Nonetheless, it is crucial to eliminate driver distraction as much as possible given the deterioration of performance on several driving measures in those with low and high attention capacity.     

Effects of fog,driver experience and gender on driving behavior on S-curved road segments

Driving on curved roads has been recognized as a significant safety issue for many years. However, driver behavior and the interactions among variables that affect driver performance on curves is complicated and not well understood. Previous studies have investigated various factors that influence driver performance on right- or left-turn curves, but have paid little attention to the effects of foggy weather, driver experience and gender on driver performance on complex curves. A driving simulator experiment was conducted in this study to evaluate the relationships between driving behavior on a continuous S-curve and foggy weather, driver experience and gender. The process of negotiating a curve was divided into three stages consisting of a straight segment, the transition from the straight segment to the S-curve and the S-curve. The experimental results indicated that drivers tended to drive more cautiously in heavy fog, but the driving risk was still increased, especially in the transition stage from the straight segment to the S-curve. The non-professional (NP) drivers were less sensitive to the impending change in the road geometry, and less skilled in both longitudinal and lateral vehicle control than the professional drivers. The NP female drivers in particular were found to be the most vulnerable group in S-curve driving.     

Associations between driving under the influence of alcohol or drugs,speeding and seatbelt use among fatally injured car drivers in Norway

Since 2005, all fatal road traffic crashes in Norway have been analyzed in-depth by multidisciplinary investigation teams organized by the Norwegian Public Roads Administration (NPRA). During the period 2005–2010, 608 drivers of cars or vans were killed in road traffic crashes. Blood samples were collected from 372 (61%) of the drivers and analyzed for alcohol and a large number of psychoactive drugs at the Norwegian Institute of Public Health (NIPH). After coupling the analytical results with the NPRA crash database, 369 drivers with a fatal outcome were identified and included. Alcohol or drug concentrations in blood above the legal limits were found in 39.8% of the drivers who were investigated for alcohol or drug impairment; 33.9% had blood alcohol concentrations above 0.5 g/L or concentrations of drugs above the equivalent Norwegian legal impairment limits or concentrations of amphetamines above 200 μg/L. Among drivers with a fatal outcome who had been impaired by alcohol or drugs, 64.6% were unbelted and 71.7% were speeding when the crash occurred; whereas 24.2% and 33.2% of the sober drivers were unbelted or speeding, respectively. Statistically significant associations were found between impairment by alcohol or amphetamines and driving unbelted or speeding. Excessive speeding is one of the main reasons for road traffic crashes and together with being unbelted the main reasons for a fatal outcome. This behavior might in many cases be due to increased risk-taking or negligence of safety measures as a result of alcohol or drug use.     

An experimental study of factors associated with driver frustration and overtaking intentions

This study examined directly the impact of various factors associated with driving on ‘A-class’ roads in the United Kingdom (specifically length of platoon, proportion of heavy goods vehicles (HGVs), speed and opportunities for overtaking) on self-reported frustration and overtaking intentions. The impact of situational variables (being under time pressure, and time behind a slower moving platoon) were also examined, as was the association between frustration and self-reported overtaking intentions. 183 members of the public from the areas around Perth and Inverness, Scotland took part in the study. Participants viewed simulated ‘driver’s viewpoint’ clips representing all the combinations of the experimental variables (except time pressure, which was a between-groups variable, and time behind platoon, which was examined separately in four specific clips). After each clip, participants responded on a paper questionnaire as to the level of frustration they would feel for a given clip, and the likelihood that at some point during the clip they would have attempted an overtake manoeuvre. The findings show that the links between traffic variables such as speed and platoon length, and behaviourally-relevant variables such as frustration and overtaking intentions, are not simple. Although there are broad and predictable effects of speed and platoon length (lower speeds and longer platoons leading to greater frustration) these are mediated by other variables, and it is not always the case that more frustration leads to more intention to overtake. Analysis of driver attitudes identified three clusters (low, medium and high risk drivers) and suggests that higher risk drivers’ levels of frustration are more affected by situational changes than those of lower risk drivers.     

Reducing the disruptive effects of interruption: A cognitive framework for analysing the costs and benefits of intervention strategies

Interruptions are ubiquitous, and they can lead to disastrous consequences. The goal of this paper is to describe remedies that have been proposed to reduce the disruption caused by interruptions based on an understanding of how principles of human cognitive processing bear on the sequence of events that take place during an interruption. We show that interruptions tap disparate cognitive operations, from attention to decision making to memory. We illustrate how these cognitive processes can lead to interruption-induced errors, and how they can help in understanding potential problems with remedies that have been proposed to ameliorate those effects. We present a framework in which the load imposed by the task and the cost of an error suggests the types of solutions that should be considered for a given domain. We then discuss the implications of this approach for understanding and reducing the negative effect of interruptions in transportation domains.     

AC PDP高阻维持驱动方法

针对AC PDP传统维持驱动方法存在零电压状态,造成两次维持放电之间壁电荷损失的问题.本文提出了一种AC PDP高阻维持驱动方法,在该方法中,采用高阻状态替换了传统维持驱动方法中的零电压状态.从而去掉了两次维持放电中间的放电通路,使得壁电荷在两次维持放电之间不会损失.实验结果表明,采用该方法,可以增大AC PDP维持电压余裕度,降低维持电压,提高维持放电的稳定性.     

The alerting effect of hitting a rumble strip—A simulator study with sleepy drivers

A moving base driving simulator experiment was carried out in order to investigate the effects of milled rumble strips on driver fatigue. There were rumble strips both at the edge line and centre line. Four different physical designs of milled rumble strips (yielding noise values from 1.5 to 16 dBA) and two placements on shoulder were used in the experiment. Sound and vibrations from real milled rumble strips were reproduced in the simulator. In total 35 regular shift workers drove during the morning hours after a full night shift. The main results showed an increase in sleepiness indicators (EEG alpha/theta activity, eye closure duration, standard deviation of lateral position, subjective sleepiness) from start to before hitting the rumble strip, an alerting effect in most parameters (not subjective sleepiness) after hitting the strip. The alertness enhancing effect was, however, short and the sleepiness signs returned 5 min after the rumble strip hit. Essentially no effects were seen due to type of strip. It was concluded that various aspects of sleepiness are increased before hitting a rumble strip and that the effect is very short-lived. Type of strip, as used in the present study did not have any effect.