Preliminary impairment tests
Strathclyde Police traffic officers are specially trained in preliminary impairment testing. These internationally recognised tests are used to measure a driver's level of impairment, and to show whether he or she is fit to drive.

Television advertisements have appeared showing motorists attempting to walk in a straight line or touch their nose with their finger. It looks and sounds simple enough - but if a driver is under the influence of a drug these tests soon show it.

If a driver is arrested after failing one of these tests a blood sample is taken and sent for analysis and an accurate record of which drug(s) have been taken is produced.