Driving under influence of drugs

DUI usually refers to driving under the influence of alcohol. But as the Daily Herald reported Monday, some law enforcement authorities are increasingly zeroing in on motorists for driving under the influence of marijuana or other illegal drugs.

That variety of DUI does occur. Maybe often. One suburban emergency room doctor told the Daily Herald that his staff regularly sees and treats drivers under the influence of drugs. And there are surveys:

• A 2004 survey of high school seniors had 13 percent saying that they had driven while high on marijuana.

• A 1993 study of truck drivers involved in fatal crashes showed that 30 percent tested positive for drugs.

• Various state studies have shown 4 percent to 14 percent of drivers killed or injured in traffic accidents tested positive for marijuana.

Illinois is among only 12 states that makes it unlawful to drive with any level of illegal drugs in the blood system. That in itself is somewhat controversial. Other states authorize arrests only if a motorist has certain levels of the drug in his blood or urine or if the driver shows evidence of being impaired when pulled over by police.

Which of these two is the better approach?

It's not difficult to argue that people who use illegal drugs in the first place have little room to complain that Illinois makes it a crime to drive with even a trace of those drugs in a driver's system.

But if the objective of traffic laws is to maintain safe roadways, then Illinois' law would be more compelling if it linked drug use to a certain blood or urine content scientifically known to cause impairment. Some prosecutors say the state must maintain a zero-tolerance policy for any level of illegal drugs in a driver's blood system in order to save lives. But if that's the case, then why does state law tolerate blood alcohol levels of up to .08 percent?

Illinois law would be more compelling even if it required police to cite indications of impairment at a crash scene or when they pull a motorist over. But signs of drug impairment typically are more difficult to detect or recognize than evidence of inebriation. Knowing that, Kane County authorities are wisely sending both police and prosecutors to specialized training sessions. Police learn physical signs of impairment from various drugs; prosecutors learn what sort of evidence they need to prove their cases in court. Appropriately, the county is using revenue from DUI fines to pay for the training.

Officials from Cook and other collar counties need to make a point of watching Kane's experience and outcomes carefully -- to determine whether they, too, need to be more innovative and proactive in identifying drivers under the influence of drugs and getting them off the road.