Drivers who have had it with the gas costs of a solo commute but who can't be tied to a daily car pool schedule may have a new option, according to the Atlanta Regional Commission.

The ARC's car pool and van pool matching service, which helps pair car poolers with partners in their area, is expanding a program that gives participants a guaranteed, free ride home if they have to miss the car pool occasionally.

On the night a commuter can't make the car pool, the ride home can take different forms, but it's delivered to the commuter, ARC officials said. If the commuter lives more than 30 miles away, they'll get a rental car.

Over the course of a year, they can use the service five nights, thanks to federal funding. But only if they took the car pool to work that morning.

In addition, the service is adding a program that matches bicycle riders who have been biking their routes alone so they can partner for safety in numbers.

The service has changed its name from 1-87-RideFind to RideSmart. The old phone number still works, at 1-877-433-3463. Commuters can call the number or use the Web site at www.MyRideSmart.com.

ARC also works with the Clean Air Campaign, which offers incentives for people to match up through the database.

The ARC ride-matching program used to limit participation to commuters whose employers had signed on, but now anyone can join.

It's all part of the ARC's emphasis not only on planning transportation projects to accommodate the area's stifling traffic, but on trying to change behavior to get some cars off the roads.