? The Insurance Institute for Highway Safety reports “The legalization of retail sales in Colorado, Washington and Oregon was associated with a 5 percent higher rate of police-reported crashes compared with neighboring states that did not legalize retail sales.”

? Colorado has the highest increase in traffic crashes, at 7.4 percent, and the most commercialized and permissive pot laws of states studied by the Insurance Institute.

? The Denver Post analyzed federal and state data in 2017 and concluded “traffic fatalities linked to marijuana are up sharply in Colorado.”

Cops and prosecutors say the numbers make sense, given what they see on the roads and in court.

State Rep. Dylan Roberts stands out among those concerned about this apparent public safety dilemma. Roberts doubles as an Eagle County deputy district attorney who has prosecuted hundreds of driving under the influence cases.

A liberal Democrat and the former Western Slopes field director for President Barack Obama’s re-election campaign, Roberts is not leading an anti-pot campaign wrapped in public safety. He supports Colorado’s “cannabis industry” but has a heartfelt concern for the public safety consequences.

Roberts sees the lives ruined by drivers under the influence of alcohol and/or drugs and wants to save lives.

As explained in a remarkably balanced and objective story by Westword writer Thomas Mitchell, Roberts introduced House Bill 1146 because of his relation “with parents who’ve lost children to impaired drivers.”

It is hard to imagine anything more traumatic than a late-night knock on the door from cops bringing news of a fatal car crash involving one or more kids. It is harder to imagine contending with that grief if the crash involved alcohol and/or drugs and could have been prevented.

Roberts and others in Colorado law enforcement assure us marijuana is a problem on the roads, but say charging and convicting for THC impairment is problematic at best. The legal threshold is 5 nanograms of THC, which poses big problems in proving impairment in court. Some law enforcement consider the conviction process so futile they seldom charge for DUI impairment.

“The 5 nanogram number is scientifically dubious, and not on the same level [of accuracy] as a 0.08 alcohol limit for drivers,” Roberts told Westword.

“Someone who’s a habitual user could be totally fine to drive at or above 5 nanograms, while someone who doesn’t use it a lot could be really impaired at 3 nanograms.”

Mitchell’s article collaborated that observation, telling of the publication’s former pot critic – a heavy marijuana user – going 15 hours without using THC. He tested at 13.5 nanograms. He was triple the “lab level” for intoxication, but a physician involved in the experiment said he was “in no way incapacitated.”