Sonoma County is part of a pilot program for a new online app called Carma, which allows drivers and passengers to link up and share rides. The program is designed to get cars off the road and reduce traffic and green house gas emissions.

The publicly funded program is different than for-profit ride-sharing apps like Lyft and Sidecar, whose drivers work for fares. Carma lets drivers see people in their neighborhood who are looking for rides, and it lets those looking for rides see who is going their way. It links the two together to share the cost of commuting.

Carma administrators say the more people use the app, the more useful it will be. Try it for yourself at www.car.ma/sfbay.