[SentraSE-R]

It's all dependent on whether you have the critical mass to keep the ball rolling - pretty iffy in your rural area. If there's a public agency that will host the software, and enough people enrolled to make a few matches, it's worth your effort. I shared rides my entire working career, with my worst lapses (motorcycling, half the time with a passenger) still being fuel-efficient.

The Bay Area has mass to spare. There are informal pick-up spots where drivers pick up riders to fill carpools for the reduced bridge toll. I think it's amazingly gutsy of passengers and drivers to pick up total strangers on a daily basis, but it's a system that works here.