The drug the risk of a fatal car accident pilots triples, and the combination of drugs and alcohol causes an astronomical increase of 23 times the risk, according to a new study.

Drugged driving is a growing safety problem in the United States and many other countries – especially with rising prescription drug abuse – but there has been little research on their role in accidents to date, the study authors said.

Researchers analyzed US government data on roadside surveys of alcohol and drug use by drivers and fatal accidents. They found that almost 32 percent of drivers involved in fatal accidents and about 14 percent of drivers of “control” in roadside surveys tested positive for at least one drug.

In general, drivers who tested positive for drugs were three times more likely than those who tested negative to be involved in a fatal accident. Depressive were associated with an increased risk of a fatal accident, followed by stimulants, narcotics and marijuana among the drugs studied.

High levels of alcohol in blood is found in about 9 percent of drivers in road surveys and 57 percent of drivers involved in fatal accidents. About a fifth of drivers involved in fatal accidents tested positive for alcohol, and one or more drugs, compared with 2.2 percent of drivers in road surveys, the researchers found.

Compared with drivers who tested negative for alcohol and drugs, the risk of having a fatal accident was more than twice as high for those who were positive drugs but alcohol-negative, more than 13 times higher for those who were alcohol- -positive, but 23 times greater for those who tested positive for both alcohol and drugs, according to the study in the journal Accident Analysis and Prevention-negative drug.