That is literally the startup I'm working on right now.
Originally was going to start working on the nightlife vertical of this market (i.e. we all live in an apartment complex or dorm together and want a shuttle to the bar district so we don't have to drive drunk) and the messaging on the site now is to that effect.
But as I've been around the country researching I'm seeing there is probably a bigger opportunity around commuters and other activities like shuttles around festivals.
If you have any feedback or suggestions feel free to contact me (info is in my profile) and also sign up on the site. I'm launching mvp in 2 - 3 weeks.