Drug and Driving: A Compendium of Research Studies

Annotated Sources (cont'd)

United Kingdom

57. Barbone, F., McMahon, A. D., Davey, P. G., Morris, A. D., Reid, I. C., McDevitt, D. G., and MacDonald, T. M. (1998)

Association of road-traffic accidents with benzodiazepine use. Lancet 352: 1331-6.

Overview

Within-person case-crossover study of crashes among psychoactive drug users

Type of study, population(s) and proportion tested

All drivers 18 years or older who experienced a road-traffic accident between August 1, 1992 – June 30, 1995, which was attended by Tayside (UK) police

Residents in Tayside and had been registered with a Tayside general practitioner between January 1992 and January 1995

Had been using a psychoactive drug at some time during the study period

Drugs examined
Method of testing and medium used
Other dependent variables
Findings (including statistical methods)

Identified 1731 users of any study drug

Using logistic regression, the odds ratios for having a road-traffic accident on a day of drug use for different drugs were:

Risks associated with benzodiazepine use:

Was significant in drivers who failed a breath test for alcohol but was much stronger in those with a positive test (this difference in risk was significant)

Benzodiazepines with a long half-life were associated with an increased risk of accident

58. Buttress, S. C., Tunbridge, R. J., Oliver, J. S., Torrance, H., and Wylie, F. (2004)

The incidence of drink and drug driving in the UK – A roadside survey in Glasgow. In J. Oliver, P. Williams and A. Clayton (Eds), Proceedings of the 17th International Conference on Alcohol, Drugs and Traffic Safety (CD). Glasgow: Scottish Executive.

Overview

Roadside survey as part of a larger case-control study

Type of study, population(s) and proportion tested

Non-accident involved drivers at sites within the area of the hospitals from which they obtained their accident-involved sample

Collected at same times of day as the people in the accident sample had their accidents

Time period from July 2003 to June 2004

Drugs examined (threshold values for detection)
Method of testing and medium used

Drivers stopped at random and asked to offer a sample of saliva and complete a questionnaire about items such as alcohol consumption, driving habits, use of drugs and medicines

Other dependent variables

None

Findings (including statistical methods)

As of March 2004, chemical analysis completed on 386 saliva samples

Eighteen drugs detected (incidence of 4.7%)

Much lower than the 22.9% found previously in their road fatality study

Ecstasy was most common, followed by cocaine and cannabis

However, only 65 of the 386 cases had been tested for cannabis so researchers suggest that cannabis is likely to be the most common once all analyses are complete

No questionnaires analyzed at this point

Comments

Study is ongoing

59. Sexton, B.F., Tunbridge, R.J., Board, A., Jackson, P.G., Wright, K., Stark, M.M., and Englehart, K. (2002)

The Influence of Cannabis and Alcohol on Driving. TRL Report 543. Crowthorne, England: Transport Research Laboratory.

Overview

Study of the effects of cannabis in combination with alcohol

Type of study, population(s) and proportion tested

Male drivers

Simulator and laboratory tasks

Drugs examined (threshold values for detection)
Method of testing and medium used
Other dependent variables
Findings (including statistical methods)

Under the influence of cannabis subjects: reduced speed, increased headway, were aware of the effects, were less accurate in maintaining lane position, had poorer tracking, performed more poorly on sobriety tests

Subjects actively attempted to compensate for the effects

Alcohol and cannabis together produced an effect slightly greater than cannabis alone

60. Tunbridge, R. J., Keigan, M., and James, F. (2002)

A comparison of the incidence of drugs in drink drivers and fatal road casualties. In D. R. Mayhew and C. Dussault (Eds.) Proceedings of the 16th International Conference on Alcohol, Drugs and Traffic Safety. Quebec: Société de l’Assurance Automobile du Québec.

Overview

Comparison of drug use trends in drinking drivers and fatal road users

Type of study, population(s) and proportion tested

Random selection of drinking driver cases from TRL for England and Wales (n=2000)

Fatal road casualties (n=1184)

Time period of 1997

Drugs examined
Method of testing and medium used

Blood sample information from Forensic Science Service

Other dependent variables

Sex, and age

Findings (including statistical methods)