PROVING POT IMPAIRMENT TOUGH WITH NO LEGAL LIMITS

Why is it so difficult to convict someone for impairment by marijuana?

Under Section 253 of the Criminal Code, a driver can be charged for
operating a vehicle while impaired by alcohol or a drug.

There is also an additional offence set out for alcohol, making it an
offence to drive with more than a certain amount of alcohol in your blood.

But there is no such specification for what level of pot must be found in
your blood before a driver is considered to be impaired, because possessing
and smoking pot in itself is illegal.

"Parliament cannot give us a legal limit for the simple reason that it is
illegal to simply use it or possess marijuana," said Crown counsel Winston
Sayson.

In addition, THC -- the active ingredient in pot -- tends to dissipate
quickly, making it difficult to pinpoint the exact level of THC in a driver
during the time he was operating a vehicle.