See
Scottish Human Rights Group Protests New "Drug" Detection Swabs;
No Practical Use In Determining Impairment

Motorists will be asked to participate in a second round of roadside drugs testing which began yesterday in a week-long trial by Scotland's largest police force. Drivers will be stopped at random and asked to voluntarily give a sample of saliva on a cottonbud swab by Strathclyde police officers.

The sample will then be inserted into a disposable cartridge where a chemical reaction takes place. An electronic evaluation instrument will read the reaction and display the results within five minutes.