That's exactly the same objection I raised, but it turns out that alcohol-related fatalities are falling at a much greater rate than overall traffic fatalities. That indicated to me that improvements in car safety, emergency response, medical care alone don't account for the drop. I believe people drive drunk less because there are increased negative consequences when they get caught. It's a reasonable conclusion to leap to.

I'm sick of this, though. The comparison between alcohol and marijuana can only be taken so far and we're far beyond the point of usefulness. For example, the number of corpses that test positive for marijuana is not useful because THC persists so long in the system. How would we even know if the law was working to reduce deaths? I'm on the fence about this law. I'm not convinced it's the best way we can reduce the number of high drivers on Colorado roads, and I'm entirely agnostic on what the limit should be. 5, 50 or 500ng are equally opaque to me.