[CutePuppy]

One reason for marked increase may be the recent attention to and availability of testing for drugs, more specifically for marijuana / THC as opposed to just alcohol.

DUI / DWI used to mean "alcohol" (and reflected in traffic statistics as such), now they are starting to separate the causes and, not surprisingly, find that marijuana and other drugs are prevalent.

[Ken H]

Yet highways deaths rates are at record lows. State level data for 2013 is available at the link that follows. Note that Colorado, Washington, and Oregon were below the national average, which was 1.11 deaths per 100 million vehicle miles traveled. DC, which has medical marijuana and just voted 2 to 1 to legalize, had the lowest fatality rate in the country.

http://www.iihs.org/iihs/topics/t/general-statistics/fatalityfacts/state-by-state-overview

[Artie]

There is also a large percentage of motorists under the influence of heavy prescription drug regimens. Some that would put me in a coma. In over 45 years of driving, I can’t recall more distracted and disengaged persons behind the wheel. Electronics and other digital devices aren’t helping much either.

[equaviator]

I wouldn’t want to be driving on the same road with someone who, for example, was driving at a .17 BAL but if I knew that the person in the next lane over, in oncoming traffic or at a comfortable distance behind me had smoked some weed with his or her cup of coffee that morning, it wouldn’t bother me as much, especially if I knew that he or she was an experienced and moderate user. However, inexperienced, underage and impressionable drivers who would otherwise be preoccupied with their “buzz” would probably not be the best judge of their own capabilities behind the wheel.

[FlingWingFlyer]

Americans don’t have to drink and drive anymore. We’ve got millions of Barry’s illegal aliens to do that for us now.

[rhoda_penmark]

“More Using Drugs [Alcohol, Marijuana, Pot]”

Marijuana and Pot combined can be lethal. /s

[ConservingFreedom]

From the original report (http://www.nhtsa.gov/staticfiles/nti/pdf/812118-Roadside_Survey_2014.pdf):

"At the current time, specific drug concentration levels cannot be reliably equated with a specific degree of driver impairment."

"Alcohol, in comparison, is more predictable. A strong relationship between alcohol concentration and impairment has been established, as has the correlation between alcohol concentration and crash risk."