Atlanta ? In 16 states and counting, drugs now kill more people than auto accidents do, the government said Wednesday.

Experts said the startling shift reflects two opposite trends: Driving is becoming safer, and the legal and illegal use of powerful prescription painkillers is on the rise. For decades, traffic accidents have been the biggest cause of injury-related death in the U.S., and they are still No. 1. But drug overdoses are pulling ahead in one state after another.

“People see a car accident as something that might happen to them,” said Margaret Warner, an epidemiologist with the Centers for Disease Control and Prevention. But as for death from a drug overdose, “maybe they see it as something that’s not going happen to them.”

The drug-related death rate roughly doubled from the late 1990s to 2006, according to the most recent CDC data.

The number of states in which drug-related deaths have overtaken traffic fatalities has gone from eight in 2003 to 12 in 2005, and 16 in 2006. They are: Massachusetts, New Hampshire, Rhode Island, Connecticut, New York, New Jersey, Maryland, Pennsylvania, Ohio, Michigan, Illinois, Colorado, Utah, Nevada, Oregon and Washington.

It’s not clear why those states have seen such a shift, but experts said certain drugs may be more of a problem in some states than in others.

While cocaine and heroin continue to be significant killers, most of the increase is attributed to prescription opiates such as the painkillers methadone, Oxycontin and Vicodin.

From 1999 to 2006, death rates for such medications climbed for every age group. Deaths from methadone alone increased sevenfold, according to the CDC.