Metrobus stop by Mathew Friedman.

Metrobus’s route numbers are unusually complicated compared to those of other major cities. Los Angeles makes do with three-digit numbers for all routes. New York has prefixes for the five boroughs (M, B, Q, Bx, and S) followed by route numbers, many of which (especially in Manhattan) reflect the street the bus runs on.

Meanwhile, Metrobus uses a mix of two-digit numbers, letters followed by one or two digits, and letters preceded by one or two digits. How did we end up with such a mess?

There are some patterns. Routes without letters are generally major radial lines in DC (but routes with letters are too). Routes with numbers before letters are in Virginia, mostly, but not always. Routes with letters followed by numbers might be in DC or Maryland.

The bus number depends on who operated it in 1973 and if it was a streetcar in 1936

This all comes from when WMATA took over the region’s private bus companies in 1973: DC Transit; the Washington, Virginia and Maryland Coach Company; the Alexandria, Barcroft and Washington Transit Company in Northern Virginia; and the WMA Transit Company in Prince George’s County. At that time, it largely kept those different companies’ numbering systems.

Capital Transit, which provided bus and streetcar service in DC and parts of Maryland until 1973, used a different numbering system based on whether a line was served by buses or streetcars in 1936.

Since the 1973 takeover, when WMATA has created new bus routes, it has often, but not always, given them numbers consistent with the old system. As a result, today’s Metrobus route numbers are a mixed bag, with many apparent rules, most of which are occasionally broken.

Lines and routes and geography, oh my!

To understand Metrobus route numbers, you have to understand the distinction WMATA makes between bus routes and lines. Each individual route number refers to a specific bus route: a particular service pattern with its own schedule. WMATA combines similar routes into groups it calls lines and gives names (but not numbers) to; all of the routes on a given line generally appear in the same schedule pamphlet, and the agency tries to give related numbers to all routes in a line.

For instance, the Viers Mill Road Line in Montgomery County consists of the Q1, Q2, Q4, Q5, and Q6. The Columbia Pike Line in Arlington County includes the 16A, the 16C, and the 16E. Often there are multiple lines with related numbers in similar areas: There's also a 16G, 16H, 16L, and 16Y, and they also use Columbia Pike. The Fort Totten-Petworth Line in DC is the 60 and 64, while the similar 62 and 63 are the Takoma-Petworth Line.

Capital Transit, which operated buses and streetcars in the District, Montgomery County, and eastern Prince George’s County, established a system in 1936 that used letters for its bus lines and numbers for its streetcar lines. Streetcar line numbers were assigned roughly west to east while bus line letters were assigned in a rough counterclockwise order around downtown from the Anacostia to the Potomac, except 16th Street NW, which was given the designation S (for Silver Spring). Letters late in the alphabet were used for bus lines that did not go downtown.

1936 streetcar map by Ghosts of DC.

The nine streetcar trunk lines in the system were the 1 (serving Rosslyn via the Key Bridge), the 2 (the Glen Echo line), the 3 (Wisconsin Avenue), the 4 (Connecticut Avenue to Mt. Pleasant), the 5 (14th Street), the 6 (11th Street), the 7 (7th Street and Georgia Avenue), the 8 (North Capitol Street, with a connection to Rhode Island Avenue), and the 9 (U Street-Florida Avenue). Streetcar tracks on H Street had already been abandoned in 1936, and so they were not included in this system.

Routes then got numbers which started with the line's letter or number followed by a number for the specific route, and successor Metrobus lines often, but not always, follow the same numbers today. So the 82 was the streetcar on Rhode Island Avenue, which entered downtown on the North Capitol Street (8) line. (This is why the current 80 bus on North Capitol and the 82/83/86 on Rhode Island Avenue seem like they should go together, but don’t overlap at all.)

Even-numbered routes had all-day, local service, while odd-numbered routes were additional rush-hour routes with express service or close-in termini. Although some odd-numbered routes today—the 83 on Rhode Island Avenue and Baltimore Avenue in Maryland most notably—are the primary routes for their line, with all-day service, odd-numbered routes are more likely to be special, rush-hour services, and almost all MetroExtra routes end in 9.

A 1942 map of Capital Transit bus (red) and streetcar (green) routes in downtown. Image by DDOT.

The former suburban transportation companies make things more complicated

The separate bus and streetcar numbering systems from Capital Transit, and the ways in which they have mutated over the years would make Metrobus’s route numbering confusing enough. However, WMATA also inherited bus lines and routes from several suburban bus companies.

Washington, Marlboro & Annapolis Motor Lines (WMA), which served much of Prince George’s County used the same letter-and-number system as Capital Transit. When these lines were absorbed into the Metrobus system, WMATA added a tens digit (usually “1”) to these route numbers to avoid conflicts with Capital Transit route numbers, so many Prince George’s County routes have a letter followed by a number between ten and twenty, like the heavily-used A12 and P12 inside the Beltway and the B21-B29 routes, which serve Bowie and Crofton.

The two main Virginia bus companies, Alexandria, Barcroft & Washington Rapid Transit (AB&W) and the Washington, Virginia & Maryland Coach Company (WV&M), both used numbers to indicate lines and added letters as suffixes for specific routes. WV&M route numbers were directly adopted by Metrobus, and conflicting AB&W route numbers were changed, keeping the same format. Virginia routes now range from the 1A and 1B on Wilson Boulevard in Arlington to the 38B, which runs from Ballston to Farragut Square along the same general route.

Here's a quick reference table of naming schemes:

Scheme Examples Company Mostly in
Number only 42, 92 Capital Transit streetcar in 1936 DC
Letter + number B2, S2 Capital Transit bus in 1936 DC & Maryland
Letter + 2 numbers A12, B21 WM&A Prince George's
Number(s) + letter 2A, 7A AB&W or WV&M Virginia

Newer numbers usually follow the pattern, but not always

As Metro has changed or added routes, it usually sticks to this same scheme. For instance, the new 14th Street limited stop bus was the 59, to go with the 52, 53, and 54. Some numbers might trick you, though. Like the 30N and 30S, which are not, as the pattern might suggest, a Virginia bus route somewhat near the 29C and 29G between Annandale and Pentagon. Instead, the 30N and 30S are local buses on the 30s route, along Wisconsin Avenue NW and Pennsylvania Avenue SE.

When the routes were restructured in 2014 so most buses only ran either on the east or west side of the line, there remained a local on the whole length, which would logically be called the 30 (like the 70 local on Georgia Avenue). But this local has two possible southern termini, Naylor Road and Southern Avenue. Therefore, the 30 gets an extra letter, making it 30N and 30S and breaking the pattern.

The 89 bus follows some of the old 82 streetcar route on Route 1, between Laurel and and Beltsville (continuing on to Greenbelt Metro), but the 87 takes highways between Greenbelt and Laurel and isn't on Route 1 at all. The 89M is a variant of the 89, not a Virginia route. Therefore, the new Rhode Island Avenue limited-stop MetroExtra bus isn't the 89, but the G9, relating to the G8 which overlaps for part of its route on Rhode Island Avenue west of the Metro station.

Next time you see a bus go by, you can at least guess something about its geneaology. Whether that helps you get around the region, however, is another matter.

DW Rowlands is a human geography grad student and Prince George’s County native, currently living in College Park. More of their writing on transportation-related and other topics can be found on their website. They also write on DC transportation and demographic issues for the DC Policy Center, where they are a Fellow. In their spare time, they volunteer for Prince George’s Advocates for Community-Based Transit. However, the views expressed here are their own.

David Alpert is Founder and President of Greater Greater Washington and Executive Director of DC Sustainable Transportation (DCST). He worked as a Product Manager for Google for six years and has lived in the Boston, San Francisco, and New York metro areas in addition to Washington, DC. He lives with his wife and two children in Dupont Circle. Unless otherwise noted, opinions in his GGWash posts are his and not the official views of GGWash or DCST.