Transit agencies in many urban areas - Chicago, Washington, D.C., and Pittsburgh, among others - typically charge patrons to use their busiest parking lots. It can keep them from filling early in the morning rush, and encourage riders to car-pool or find other ways to reach a station.

The Regional Transportation District, however, cannot legally require any commuter to buy a ticket or feed a meter before securing a spot at its park-n-rides.

Senate Bill 88, by Sen. Jennifer Veiga, D-Denver, and Rep. Joe Rice, D-Littleton, would change all that, and we welcome the prospect.

The bill would allow RTD's board to charge some riders who use the district's park-n-rides. It would target commuters who live outside RTD's taxing district, leave their cars in lots for more than 24 hours at a time, or use a park-n-ride but do not ride transit - say, people who work near a station but want to avoid paying for parking at a meter or a private lot.

The board would have the leeway to decide which lots, if any, would charge commuters. One proposal would set a $2 daily fee for out-of-district motorists. As many as 15 percent of the spaces in any lot could also be reserved for paid parking, possibly using meters or the payboxes you see in commercial lots. And the board could fine drivers who leave their cars in lots overnight.

We've long said that RTD should have this authority. It's not unusual for a number of RTD's park-n-rides to fill early most weekday mornings and stay packed all day.

And people who live in towns outside RTD's sales tax region, such as Castle Rock, can now park at the Lincoln or Mineral light-rail stations . . . and not pay a penny for the privilege. That's unfair to the residents who pay the RTD sales tax on top of their bus or train fares.

SB 88 has passed the Senate and is now before the House transportation committee. It deserves an express trip to Gov. Bill Ritter's desk. Time to make the free-riders pay up.