Once again, there is a chance for Colorado to establish limits on the amount of marijuana drivers can have in their systems.

And once again, such a common-sense effort may fall victim to the obfuscation tactics of medical marijuana advocates.

We surely hope not.

Members of a state drug policy task force, who will receive a report on the issue today, have the opportunity to advance the idea that Colorado should have a limit on the amount of THC, the active ingredient in marijuana, drivers legally can have in their systems.

The idea is similar to drunken- driving blood-alcohol limits and would improve law enforcement’s ability to enforce prohibitions on drug-impaired driving.

Medical marijuana advocates have employed all sorts of arguments to convince people that the science is fuzzy on trying to measure impairment levels, or that the 5 nanogram level that was included in last year’s failed legislation is too strict.

We reject both of those arguments. If anything, the 5 nanogram is too lenient. At least a dozen states have criminalized any amount of THC in a driver’s bloodstream. Several others have a 2 nanogram limit. Pennsylvania has a 5 nanogram limit.

Furthermore, state health and law enforcement officials have previously examined the relevant studies and settled on the 5 nanogram level.

Last year’s version of the bill was supported by defense lawyers and lawyers representing medical marijuana interests. We had confidence in their assessment and still do.

Arguments you’ll hear from those opposing such limits are that THC lingers in users’ bloodstreams for a long time after consumption, and that regular users develop a tolerance for THC.

In fact, drug experts will tell you that THC bloodstream levels drop within hours of marijuana use.

And just because some folks are habitual pot users and have learned to adapt their behavior to get along most of the time doesn’t mean they have the reaction times and judgment necessary to be safe drivers.

The same argument could be made about the chronic drunk who manages to drive himself home 99 percent of the time. It’s the 1 percent that’s a problem.

Today, members of a drug policy task force will receive a THC limit report. Before long, they will decide whether to recommend that the state’s Commission on Criminal and Juvenile Justice support another try at legislation.

We hope they go that route, despite prognostications that a majority of state lawmakers will not be inclined to support such a measure.

Though drunken driving is a much bigger issue in general, marijuana-impaired driving incidents are increasing rapidly and our state’s laws need to keep up with this potentially deadly problem.