RIVERSIDE (CBS) — One suburban police chief thinks law enforcement agencies across the state need to be better prepared if and when medical marijuana becomes legal in Illinois.

WBBM Newsradio’s Dave Berner reports Illinois lawmakers have passed legislation allowing doctors to prescribe marijuana to patients with whom they have an existing relationship and who have at least one of more than 30 medical conditions listed on the measure.

Weitzel said the proposal on the governor’s desk provides for no waiting period between the time a patient is allowed to use marijuana and when he or she can get behind the wheel of a car.

It would still be illegal to drive under the influence of cannabis, prescription or not, but Riverside Police Chief Tom Weitzel said police won’t be able to reliably determine if someone is driving while high.

“Standard field sobriety tests for alcohol will not detect drug-impaired driving,” he said.

Weitzel, a member of the legislative committee for the Illinois Association of Chiefs of Police, said the only thing that can do that is a certified drug recognition officer, who can test in the field.

“Prosecution is dependent on this training. If you don’t have this training, those cases where you arrest for driving under the influence of drugs is going to be tossed in court,” he said.

Weitzel said his department has one such officer, and he’d like to see every police department with at least drug recognition officer.

Right now, there are only 35 in the entire state, he said.

“These officers have the expertise to see the mannerisms, can still testify in court as an expert witness, and we will have some physical evidence to go forward; versus now, we’d have nothing,” he said.

That’s because, in a DUI case, unless there is an immediate fatality, a driver may refuse blood and urine tests for drugs and alcohol.

However, supporters of the legislation maintain federally approved field-sobriety tests are adequate to determine impairment from drug use. Supporters have said standard field sobriety tests are admissible in court, and the “divided attention” tests would sufficiently evaluate a driver’s hand-eye coordination, and his or her ability to maintain balance and listen to instructions.

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