The effects of marijuana use on driving performance have been extensively researched over the last 20 years. All major studies show that marijuana consumption has little or no effect on driving ability, and may actually reduce accidents. Here's a summary of the biggest studies into pot use and driving.One poster at the WTF.com message boards has this to say:
A 1983 study by the US National Highway Transportation Safety Administration (NHTSA) concluded that the only significant affect of cannabis use was slower driving - arguably a positive effect of driving high. - Cannisbusculture.com
You know what the difference between a drunk driver and a stoned driver is?
A drunk drives through the stop sign, and a stoner waits for it to turn green