According to the National Highway Traffic Safety Administration (NHTSA), around 22,000 drivers died behind the wheel last year, and almost 4000 of those were found to have drugs in their system.
And the total is expected to be even higher, with only 63 percent of those 22,000 drivers tested for drugs.
Of all the drivers who were killed and tested after their accidents, around one in three were found to be under the influence of drugs.
Both legal and illegal drugs were recorded in the test, including cocaine, heroin, LSD, marijuana, methadone, methamphetamine, morphine, prescription drugs and inhalants. Alcohol, aspirin, nicotine and drugs administered after the crash were not included in the results.
The results were higher than in 2005, when about 13 percent of the 27,000 drivers killed in car crashes tested positive to drugs.
NHTSA administrator, David Strickland, admitted there were still many unknowns about the effects of specific drugs and their ability to impair drivers, and insisted that more research was needed.
He did, however, confirm the new data pointed towards a growing problem of people driving under the influence of drugs.
“Today’s report provides a warning signal that too many Americans are driving after having taken drugs, not realising the potential for putting themselves and others on the highway at risk,” Mr Strickland said.“Drugged driving is as inexcusable as drunk driving or driving irresponsibly.”