Except from WMATA's bus map. Photo of WMATA product by the author.

Every bus agency in the Washington region has some kind of system it uses to decide which bus route gets which number. This post, and the handy printable infographic below, is a guide to help you decipher what those numbers mean.

Most people only know the buses they use, plus maybe a few other important ones around the region. It’s impractical to memorize all 400-some bus routes in the region, after all. But knowing what those numbers mean—why the Q4 is the Q4 instead of, say, the 861H—can help you understand the entire system without necessarily memorizing it.

Print this field guide to local bus numbering

Here’s the one-page summary of how each of the largest regional bus systems numbers routes. It’s a little small to read on-screen, but it looks great printed.

Click for the printable version. Image licensed under Creative Commons.

Metrobus versus everybody else

WMATA has both the largest bus system and the most complex numbering scheme in the region. Every number and letter in every WMATA bus name means something, either in terms of where the bus in located or what kind of service it provides. In 2018, D.W. Rowlands wrote an excellent guide to what they all mean.

For Metrobus, the basic system uses the first digit to identify a line family, and the last digit to identify the specific route in that family. So in DC, for example, the 52, 54, 59 are all similar routes on 14th Street. The 2, 4, and 9 in their names tell you about the slightly different routes you can pick from along that trunk line. Odd numbers only run at peak times, with even numbers all-day. Low numbers are locals, high numbers rapid.

Most of the other bus agencies in the region number routes according to what geographic area of the county they run through. Fairfax buses numbered in the 100s run near Mount Vernon, versus buses in the 500s that run near Reston, for example. Fairfax, Arlington, Montgomery, and Prince George’s all follow this basic structure.

Alexandria simply numbers routes sequentially according to when they began running. 1 was the first DASH bus, 2 the second, and so forth.

DC Circulator names its routes based on destinations. The Georgetown-Union Station route has no other designation, except that it’s sometimes shortened to GT-US, and sometimes unofficially called the K Street Circulator since it spends much of its time there.

These are of course just the main bus agencies in the immediate Washington area. Many others aren’t included, and may have useful naming schemes. If you know of the scheme for smaller agencies like the Fairfax CUE, further-out agencies like the Frederick TransIT, private agencies like the University of Maryland UM-Shuttles, or any of our region’s vast network of commuter buses, let us know in the comments!

Dan Malouff is a transportation planner for Arlington and an adjunct professor at George Washington University. He has a degree in urban planning from the University of Colorado and lives in Trinidad, DC. He runs BeyondDC and contributes to the Washington Post. Dan blogs to express personal views, and does not take part in GGWash's political endorsement decisions.