Driving under the influence of drugs
Tests for drug driving
Driving is a complex task where the driver continuously receives information, analyses it and reacts. Substances that have an influence on brain function or on mental processes involved in driving will clearly affect driving performance.
Current research continues to investigate the broad spectrum of issues that require investigation if the detection of drugs whilst driving is to be addressed. These range from:
- How to detect levels of drugs in the body,
- How to detect impairment,
- The level of each drug that can effect driving performance, and
- The timescale over which each drug remains in the body.
The complexity of developing reliable testing devices for drugs is an onerous task. Tests to detect impairment from alcohol are based on the clinical understanding of it’s metabolic rate and excretion from the body, as well as dose related neuropsychological impairment. Comparable tests to detect drug levels in the body remain elusive. This is due to the differing effects on the body, the length of time remaining in the body, and the diverse assortment and combination of drugs that are taken illegally and legally by drivers. This means that levels of any drug cannot be related to measurable and repeatable effects on driving performance.
In 2000, training was introduced for police officers to detect impairment using roadside tests (currently voluntary for drivers). These tests will not prove impairment, but will provide officers with a basis for deciding whether or not to arrest a driver under section four of the Road Traffic Act 1988 - read more here
Further information
Department for Transport Local Government and the Regions - read more here
Roadside Testing assessment - read more here
Further reading
US National Library of Medicine - go to the website here
Kintz, P. et al. Detection of cannabis in oral fluid (saliva) and forehead wipes (sweat) from impaired drivers. Journal of Analytical Toxicology 2000;24(7):557-561
From this study conducted in France it was concluded that a current limitation in the use of these specimens for roadside testing is the absence of a suitable immunoassay that detects the parent compound in sufficiently low concentrations.
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