Private Mini Bus Companies?

Check out Tory Gattis' peice on Jitney Service in Houston.  In case you're wondering, a jitney service is a small capacity vehicle, like a van that runs a route and is owned by a private company.  It's somewhere between a taxi and a bus and can cover small service areas that have a lot of travelers but little parking space and lots of congestion.  This is a very common practice in Mexico, and makes a lot of sense.  Right now taking a bus to a destination about 2 miles away anywhere outside of downtown in SA takes about 30 to 45 minutes.  I could walk there faster.