Drivers suspected of being under the influence of drugs other than alcohol will soon be required to submit urine, blood or saliva samples on demand by police officers, the CanWest News Service reported June 25.

Under a law that goes into effect July 1, suspected drug-impaired drivers will face roadside tests similar to those required of drunk drivers, and also can be required to submit samples for drug testing back at the police station. Those who fail to comply will face fines of $1,000 or more.

The law was the result of five years of legislative debate and remains controversial. Critics note that while there are established thresholds for alcohol impairment based on blood-alcohol content, drug tests merely detect the presence of substances -- in some cases the chemical markers of drugs taken days, weeks, or months earlier.