Palm Beach County buses: Palm Tran routes will get green lights at intersections. - Sun Sentinel

This works only on two east/west routes, but one is Route 63 that goes from Lake Worth to Wellington. And it will only give buses preference if they are running late. It might save three minutes on the overall trip time. The article notes that bus travel in Palm Beach County currently takes about three times longer than a typical trip in a privately owned vehicle. Click title for link.

People who rely on public transportation to get to work and school need buses that run on time.
To make sure that happens, Palm Beach County will soon try out a system that keeps traffic signals green for buses long enough for them to get through an intersection, allowing bus drivers to shave a few minutes off their routes.
The system will debut on two of the county's busiest bus routes: One that travels betweenWellington and downtown West Palm Beach and another that travels betweenWellington and Lake Worth.