Taken from a US site

Drugs other than alcohol (e.g., marijuana and cocaine) are involved in about 18% of motor vehicle driver deaths. These other drugs are often used in combination with alcohol.5

In 2010, 10,228 people were killed in alcohol-impaired driving crashes, accounting for nearly one-third (31%) of all traffic-related deaths in the United States.1

http://www.cdc.gov/motorvehiclesafety/impaired_driving/impaired-drv_factsheet.html

Therefore to increase your survivability on the road, drink and smoke weed, because the other 82% killed were not on drugs
and 69% were stone cold sober..

Government statistics can be read both ways..