HOW HIGH IS TOO HIGH FOR DRIVING?

As medical marijuana laws evolve in Colorado, the legislature should
set limits for how much pot it takes to impair drivers.

Even for those who believe marijuana has useful medical applications,
we hope there is no debate about driving while stoned.

But where do you draw the line?

Colorado lawmakers next month should take up a plan to set safe
limits of marijuana use for drivers.

Certainly drivers can't be under the influence, but is it OK to have
some pot in your system, just as the law allows drivers to have some
alcohol in their system so long as it doesn't surpass certain levels?

We think some sort of demarcation is smart and necessary in a state
that allows tens of thousands of its residents to legally use
marijuana as therapy. Right now, current state law amounts to a
zero-tolerance policy when it comes to pot's psychoactive component
in the bloodstream.

The General Assembly's criminal and juvenile justice commission is
recommending that Colorado law allow for traces of THC - the
psychoactive component of marijuana - in the blood. As with alcohol,
the law would delineate when too much of the substance is present to
allow for safe driving.

"It will bring some clarity to the issue of whether you are or are
not impaired under the influence of marijuana," state Rep. Claire
Levy, D-Boulder, told The Denver Post's John Ingold.

The commission's recommendation would allow a driver to have up to 5
nanograms per milliliter of blood, but even some members of the
commission question that limit. Frequent smokers - like the medical
marijuana users the law is poised to protect - have higher tolerances
to the drug, making the 5 nanogram-limit potentially too restrictive.

We admit that we aren't pot scientists, so we don't know what to make
of the proposal. But Ingold cites accident figures that underscore
our concern that some limit be set.

In 2009, THC or other forms of marijuana were found in drivers killed
in one in five accidents that involved drugs nationally, according to
the National Highway Traffic and Safety Administration. In Colorado,
THC or other forms of marijuana showed up in the bloodstreams of 26
of 312 drivers killed that year.

As has often been the case since the advent of Colorado's medical
marijuana laws, lawmakers must break relatively new ground. Beyond
states with zero-tolerance policies, only a few, including
Pennsylvania, use the 5 nanogram limit.

Sean McAllister, an attorney involved in the commission's work,
questions the 5 nanogram limit. But he also recommends that medical
marijuana users not use the drug for four hours prior to driving.

As with some prescription medications, medical marijuana is just too
potent for safe driving.

"No responsible advocate of legalization believes that people should
be driving high," McAllister said.

We hope the commission's recommendations find their way into a smart
piece of legislation next session that not only addresses the rights
of medical marijuana patients but the overall safety of motorists.