Metro is working hard to develop “priority bus corridors,” with express buses that run more often, more quickly, and more reliably than existing service
Like a lot of transit planners, I use the word express in a more precise sense, as one of three kinds of stopping pattern that seem to encompass most successful transit services:
- Local means stopping frequently all along the line. Locals are designed on the principle that if you’re on the line, you should be very close to a stop. Local stops are usually no more than 1/4 mile (400m) apart, and often much less. Becuase they stop the most often, these services are characteristically slow. Local buses and streetcars/trams usually fall in this category.
- Limited or Rapid means stopping at a regular but widely-spaced pattern. The spacing is usually at least every 1/2 mile (800m) or sometimes wider, but the point is that the spacing is fairly regular along the line. These services are meant to link nodes of activity, often activity centers and transfer points, with a reasonably fast service. They are not trying to be available at every point on the line, although some provide a high-enough quality of service that they’re worth walking some distance to. Most subways and light rail systems are of this kind. The new generation of Rapid Bus and Bus Rapid Transit services, which more or less try to duplicate what rail transit does, generally function this way as well.
- Express, in these terms, really means “serving a very long nonstop segment.” The classic express bus may run local or limited-stop for a while, but then it has a long segment, perhaps on a freeway, where it doesn’t stop at all. A common example is the peak express bus routes, which run from a suburban park-and-ride to a worksite or from a neighborhood to a distant school. Commuter rail lines also often run express segments during the peak period.
The reason I try to use the words this way is that hiding inside this distinction about stopping patterns is a really important distinction about frequency. Rapid and Express are both ways to be faster than a Local, but Rapid lends itself to high-frequency all-day operation, while Express does not.