Are bad drivers more impaired by alcohol? Sober driving precision

predicts impairment from alcohol in a simulated

driving task

學生：董瑩蟬

Purpose

To Investigate the alcohol effects for driver skill level and understanding interactions.

ReferenceYear Author Result

2004 Evans There has up to 40% of alcohol fatal accidents in U.S.

2004 Keall et al. The young driver has high risk then older driver of alcohol accident

1985-1995

MitchellHolloway

Investigate the alcohol impair of driver skill and performance for the young drivers

1989-2005

Laberg et al.Fillmore

Alcohol slows RT, reduce hand steadiness, decreases inhibitory control, and impairs pursuit rotor tracking

Method

1.Subjects– 28people(14M,14F)– Range-21 to 31(mean(S.D)=23.8(2.9))– All subjects has no disorder – Driver for at least 3 years, and drove at least t

wo times a week.

2.Equipment– STISIM– Computer– Vehicle– Intoxilyzer, Model 400

Method3.Dependent variables (DVs)

– Driving performance：• within-lane position• within-lane deviation• speed (mph)

– Subjective measure：• subjective intoxication• subjective impairment • perceived beverage content scale

Method

4.Independent variables (IVs)– Gender– Group-Alcohol or placebo

5.Other measure– Personal drinking habits questionnaire– Blood alcohol concentrations– Baseline driving performance– Post-treatment testing

Method

6.Procedures– 14(7M,7F) subject were either alcohol or

placebo group– Two Training require subject to maintain

vehicle speed of 45 mph and to drive in the center of lane

– One trial require subject drive 80000 ft (about 20min)

– When subject finished baseline then they drink alcohol at 40 min after trial again.

– Subjects finished two experiments which were separated by a minimum of 24 h.

Results

Alcohol use -Personal drinking habits questionnaire

• subjects mean weekly dose of 3.2 ml/kg (S.D. = 2.7).

• The mean number of months of drinking was 80.7 (S.D. = 41.1).

• There was no significant differences between the alcohol and placebo groups for any measure, the same with gender.

Results

Blood alcohol concentrations

• When the post-treatment test began, the mean BAC was 70.6(S.D.=14.6)mg/100ml

• Finished the test mean BAC was 90.4(S.D.=10.8)mg/100ml.

• BAC was no significant difference in gender.

Results

Baseline simulated driving performance

• There was no significant difference on group or gender.

• The mean within-lane position for the entire sample was 5.9 ft (S.D. = 0.4).

• The mean within-lane deviation was 0.75 ft (S.D. = 0.21),

• The mean speed was 44.8 mph (S.D. = 1.0).

ResultsTreatment effects on simulated driving performance

Fig. 1. Meanchange in within-lane deviation in response to 0.65 g/kg alcoholand a placebo. Capped vertical lines indicate standard error of the mean.

ResultsRelation of initial skill to individual differences in post-treatment change

Fig. 2. Scatter plots illustrating the relationship between drivers’ initial (baseline) within-lane deviation scores and their pre- to post-treatment change in deviation scores in response to 0.65 g/kg alcohol or a placebo.Least-squares regression line is shown for each dose condition.

Results

Subjective effects

Discussion

Compared with placebo, alcohol reduced driving precision, find the increased within-lane deviation under the alcohol.

Drinkers have the capacity to employ compensatory strategies to resist the impairing effects of moderate doses of alcohol. (Vogel-Sprott and Fillnore, 1999)

Discussion

Impulsivity has been identified as a potentially important personality trait that could affect driving behavior and contribute to accident risk (Loo, 1979； Owsley et al., 2003)

Conclusions

Alcohol reduced driving precision

Baseline skill levels showed the greater impairments in response to alcohol.