The state’s new marijuana law had been officially on the books for less than a week when it got its first poster boy.

Caleb Anderson, 20, of Gloucester is accused of slamming his car into a packed school bus Wednesday morning. All 36 of the Gloucester middle school students were taken to a local hospital to be checked out and met by their much relieved parents.

Yes, this could have been a lot worse.

Gloucester police say the first thing they noticed when they responded to the scene of the crash was that Anderson’s car reeked of marijuana, and they noted that the driver admitted to smoking a blunt shortly before the accident. That Anderson tended to “stare off into nowhere with a blank expression” during his encounter with police was yet another clue that the guy might have been — dare we hint at it — impaired after having consumed what is now a legal product.

So what to do?

The ballot question eagerly embraced by voters in November doesn’t really have any answers to that. That is the problem with ballot questions. And the Legislature is only meeting in informal sessions until it formally reconvenes in the new year.

But lawmakers seem to be taking their usual glacial approach to fixing a law they readily acknowledge needs a good deal of fixing before it is fully implemented. They seem to be more concerned with the level of taxation and the zoning requirements for those future pot shops which will dot the landscape — all legitimate issues — that will require some scrutiny.

But there are some things that simply can’t wait — one is finding a way to deter people who want to smoke a joint from getting behind the wheel of a car. The issue of judging the level of intoxication is a tricky bit of business. As Mark Leahy, executive director of the Massachusetts Association of Chiefs of Police, told the Herald, “We have no objective, quantifiable way to measure THC like we do with the presence of alcohol in the blood stream.”

True, but come on folks, this isn’t rocket science. You can’t sit behind the wheel with a can of beer in your hand or in that coffee cup holder. That’s illegal. It’s a violation of the state’s entirely clear, open container law.

The very same policy can and must be implemented with regard to marijuana and marijuana products. You smoke behind the wheel, you are in violation of the law. That ought to be the Legislature’s first priority — unless, of course, they want to wait for a real tragedy.