Awesome. Carpooling for Byteballers would be super cool.
Not sure about if driver should lose all bytes in case of incomplete trip, I recently had a Uber ride where driver made a small crash mid-way to destination. I stepped out and got billed in full, but Uber refunded me half of the trip a day later.
Probably would need something extra on the wallet app too, because if have many rides per day then it can be tedious to empty each smart-contract one by one.