It happens during nearly every session of the Oregon Legislature. Lawmakers from the rainy Willamette Valley propose to tax — or even ban — studded snow tires used, we suspect, mostly by folks on the colder east side of the Cascades. This year there are at least three such proposals.

Two would impose fees on tire dealers that would be collected on each studded tire sold. The third would require the state to figure out how many drivers use studs and how much damage they do to the roads. The state then would issue permits to use the tires, the cost of which would be based on the estimated damage done.

We might be persuaded that one of the three might be reasonable, but only if a couple of things happen.

First, the state must come up with a realistic estimate of the cost of studded tire damage to Oregon roads. That’s no simple task, unfortunately.

Research on the subject is mixed. Oregon’s Department of Transportation says it spends about $11 million a year on studded tire road repair, but the estimate is based on figures now more than a decade old. Meanwhile, the state clearly does not repair all road damage each year, whether caused by studded tires or not.

Too, the state must have real numbers about how many studded tires are used each winter in Oregon. ODOT’s estimate that 19 percent of drivers use studs dates to the mid-1990s. Yet today’s conventional snow tires are far better than their predecessors and, unless roads are very icy, actually safer than studs. Their use has been growing as a result.

Given the shakiness of the information available, any attempt to tax drivers so they cover the full cost of repairs is itself on shaky ground.

Studded tires are not the only way to assure safe wintertime driving, but they have their place. If the state can demonstrate with current numbers and sound science the damage they do, then a well-designed fee or permit system might not be unreasonable. Without good numbers and good science, it is.