We need a trade-a-ride program for people needing a ride like Paperbackswap does for books. To be honest, I wasn’t thinking of commuters when I thought of this. I was listening to a Science Friday program on brewing beer while sitting in traffic and thought, we don’t have good public transportation so people often don’t drink responsibility – what if people took turns being the designated driver. And not going to the party and drinking coke but just showing up at the end of the evening to give a ride home. If you made a good social networking application with good tools, people could send a text message when they needed a ride and people that said they were available would get a text message. A potential driver could then accept the ride, key in when they would be there and go give someone a ride. You’d get points for miles. Then you could use your miles to request a ride from someone else. (On a different night of course.) It’d be useful for nights on the town, rides to the airport, times when your car is in the shop … and maybe just plain old carpooling.
There’d be some security problems. You might want to make everyone show up somewhere and show their driver’s license so you could verify who they were if there were any issues. And you’d want to only give addresses to people actually giving rides. Maybe you could start with a known "safe" pool of people like a university where you know everyone’s identity.