Driving under the influence and driving impairment

Driving under the influence and driving impairment

Drinking while driving (DUI) is still one of the main factors in accident causation. For an overview of drunk driving statistics in the US, click here. This is especially the case with young (male) drivers who combine the following risk factors that interact into severely increased accident risk and road fatalities in this group:

  • Inexperience. Young drivers are typically inexperienced drivers. That implies that driving still requires a lot of controlled attention, while in experienced drivers driving skills has become ‘automatic’ to a much higher degree. Skills that require controlled attention deteriorate much easier under the effects of factors such as intoxication (by alcohol and drugs) and fatigue. In several studies it has been shown that driving performance is more strongly affected by alcohol in young drivers compared to drivers with more driving experience. This is an important factor that results in more road fatalities in young drivers as a result of DUI.
  • Overestimation of skills and increased risk taking. Young (male) drivers overestimate their driving skills to a higher degree than other groups. While it is true that young drivers are characterized by faster responses and smaller reaction times, it is also true that reaction time is hardly a factor in accident causation. This has been clearly demonstrated in a lot of scientific research. People with faster responses often tend to take more risk by driving faster and choosing smaller headways to the lead vehicle. Young drivers usually take more risk and are poorer at estimating the effects of various factors on driving behaviour. This results in poorer anticipation and preview, insufficient increase of headway when the road becomes slippery, insufficient reduction of speed with an upcoming road curve, etc. Because they overestimate their skills, they tend to think they can overcome the negative effects of alcohol on driving performance by concentrating better, which is an obvious error in judgement.
  • Negative effects of alcohol on performance.
    • Alcohol affects motor skills resulting in increased reaction time and poorer steering control.
    • It also results in blurred vision. This makes detection of hazards even more difficult.
    • A typical effect of alcohol is that people get overconfident and they tend to overestimate their skills even more. This interacts with the overestimation of skill level that young (male) drivers already have.
    • From a traffic safety point of view, the most detrimental effect of alcohol is that people are often unaware of the performance deteriorations that are caused by alcohol. Because they are unaware of the negative effects, they don’t compensate their behaviour by driving slower of by anticipating better or taking a longer preview.

Because of these effects of alcohol on a group of drivers that is already more at risk, a car simulator is an excellent instrument to make young drivers become more aware of the effects of alcohol on their driving behaviour. When young drivers have really convincingly been demonstrated the effects of DUI on driving performance, they hopefully will think twice before drinking when they have to drive a car. To read more about the accident risk of young drivers, click here… To read more about the effects of alcohol on driving performance, click here….