DUI per se laws, stricter law enforcement, education, and changing social norms have led to a steady decline in the incidence of drunk driving and drunk-driving deaths according to NHTSA:

But changing social norms and a lack of effective drug per se laws that have hindered law enforcement, have led to a dramatic increase in drugged driving. This chart shows the percentage of fatally injured drivers positive for drugs.

Patterns among Colorado drivers are similar … READ MORE