How High is Too High To Drive?

There are more motor vehicle accidents in states that have legalized marijuana than in those where marijuana is restricted or illegal.

That’s according to a recently published study by the Insurance Institute for Highway Safety and Highway Loss Data Institute . Furthermore, the crash data suggests that as more states legalize recreational marijuana, more effort will be needed to determine how best to prevent impaired driving crashes.

But how much is too much? And how should it be measured?

While many states have have laws against driving while high, their enforcement proves difficult. The plant’s psychoactive substance THC is almost undetectable in breath and may persist for days after use in blood, ruling out the effectiveness of traditional test methods.