Drivers impaired by prescription drugs are causing more and more accidents, but law enforcement officials and prosecutors are struggling with how to deal with motorists who are under the influence of medications that they take for legitimate health reasons.
“In the past it was cocaine, it was PCP, it was marijuana,” Chuck Hayes of the International Association of Chiefs of Police told The New York Times. “Now we’re into this prescription drug era that is giving us a whole new challenge.”
Officials say that setting limits for prescription drugs is challenging because there is no agreement on what level of drugs in the blood impairs driving. In addition, a medication’s side effects can vary from person to person, and a drug can linger in the bloodstream for days, making it hard to determine when it was taken by a driver.
The problem has become so prevalent that many states are scrambling to obtain drug detection technology and to train hundreds of police officers to identify signs of drug impairment.
In the absence of specific standards, law enforcement officials around the country say anyone who drives while taking prescription drugs is at risk of arrest, whether or not they are driving recklessly.
But critics say that authorities are overreaching. Defense lawyers say that police are unfairly punishing people following their doctors’ orders, and one attorney general from Wisconsin told The Times that she usually restricts her so-called drugged driving prosecutions to motorists who had mixed medications, exceeded dosage levels or ingested controlled substances without a prescription.
“How do we balance between people who legitimately need their prescriptions and protecting the public?” said Mark Neil, a senior lawyer at the National Traffic Law Center, which works with prosecutors. “It becomes a very delicate balance.”
The scope of drug-impaired driving nationally is unknown, since state records often do not distinguish between drunk and drugged drivers. A 2007 survey by the National Highway Traffic Safety Administration found that 16.3 percent of 5,900 nighttime drivers tested positive for legal or illegal drugs.

