A proposal to let any driver use an express lane on a freeway during off-peak hours strikes us as unnecessary and self-defeating.

There might be exceptions, of course, such as when a wrecked car or truck closes a regular lane or lanes. Then it would make sense for the Highway Patrol to direct drivers to use the express lane to get around the bottleneck, whether they qualify or not.

But otherwise, we think the state should stay with the existing rules.

Those rules allow buses, cars carrying at least two people, motorcycles, and clean-fuel and emergency vehicles to use the express lane. Solo drivers who pay a fee of $50 a month also may use it.

The original idea of the lane was to encourage people to carpool or share rides. That reduces the number of vehicles on the road, which cuts down on congestion and air pollution. By the same rationale, the lane is open to motorcycles and some hybrid vehicles, which are fuel-efficient. The incentive is the special lane.

The lane was opened to solo drivers who pay a fee when the transportation department figured out that the lane was underutilized.

Now Sen. Karen Morgan, D-Cottonwood Heights, is working on a bill that would open the lane to all comers during off-peak hours. She argues that the freeway would be more efficient and, besides, all motorists should be able to use the lane because all taxpayers have paid for it.

Both of Morgan's points are true, but they are equally true during rush hour. By her rationale, you might as well do away with the express lane entirely. Maybe that's her ultimate objective.

Otherwise, changing rules will only cause confusion and muddle enforcement. Letting anyone use the lane except, say, 7-9 a.m. and 4:30-6:30 p.m., will cause driver confusion. To combat that, new signs would be necessary. People don't always observe the rules now, either because of ignorance or naked self-interest.

Besides, opening the lane on I-15 during off-peak hours isn't necessary, at least not yet. That's when traffic flows best.

Saturdays are a different matter. Traffic in south Salt Lake County is busy during most daylight hours that day. Would the express lane be open to anyone all day on Saturdays?

There may come a time to change the rules for express lanes, but this proposal sounds like more trouble than it's worth.