This video from StreetFilms was launched in February 2011. It examines the types of bicycle racks in use on public buses in major US cities and the experience of users, transport planners. Over the last ten years (or more) just about every major city in the U.S. has added bike-carrying capacity to their buses. Cities like Chicago, Las Vegas, Kansas City, Seattle, Philadelphia, and San Francisco can boast 100% of their bus fleet sporting bike racks.
The video puts a case for bicycle racks on buses in New York City but the case is the same for any major city where cyclists have long distances to travel, are required to negotiate narrow birdges or steep hills, or need to connect with public transport.