USA Today, July 27, 2014
"A small group of volunteers spent much of the last year getting drunk and stoned on marijuana furnished by the federal government before getting behind the wheel.
The volunteers were part of what federal scientists say was the most comprehensive study ever conducted on how marijuana, and pot combined with alcohol, affect drivers. The data now being analyzed ultimately will help regulators decide how stoned is too stoned to drive. It's similar to the studies conducted to develop levels for drunken driving. Volunteers were recruited from around Iowa City, home to the University of Iowa's National Advanced Driving Simulator." Read more