As drunken-driving deaths are dropping, law enforcement are seeing an increase in cases of driving under the influence of drugs—namely prescription drugs. Unlike with alcohol, however, there is no agreement on what level of drugs in the blood impairs driving and behavioral effects of prescription medications vary widely.

“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.”

There is no reliable data on how many drivers are impaired by prescription drugs, but law enforcement officials say the problem is growing so quickly that states are putting hundreds of police officers through special training to spot signs of drug impairment and clamoring for better technology to detect it.

Convictions are also more difficult to achieve in cases of impaired driving due to prescription drugs as it is often hard to convince a jury of wrongdoing if the defendant was taking prescription medication as directed.

Source: The New York Times