Social ridesharing app --  If your friends or friends of friends (on fb, linkedin, gmail/google+, etc) are going in a similar direction, they can be advised to pick you up, and vice versa. This would avoid legal problems with hitchhiking (not to mention safety issues). And then you could bring on "friends of friends," people who work in same company as you, etc. to expand network into, ultimately, a general rideshare.