Have you ever wondered how your bus route got its number?
Why is it called the 91? The O12? The Y45? The 71B?
The numbers may seem arbitrary, but some of our route numbers are rooted in a method that dates back to the days of the Pittsburgh Railways streetcar system of the 1880s.
Routes that start with a letter indicate the “line” that bus is using.
G - GREEN line. These routes use the West Busway.
O - ORANGE line. These routes use the I-279 HOV lanes.
P - PURPLE line. These routes use the East Busway.
Y - YELLOW line. These routes use the South Busway.
You can sometimes see these line colors depicted in our maps in addition to our more familiar Red and Blue light rail lines.
Routes that end with a letter are usually variations of the main route. For example, the 61A, 61B, 61C and 61D all follow similar paths out of Downtown, but take riders to different places. The same is true with the 87s, which serves Stanton Heights, and the 87m, which serves Morningside. Not all variants have these letters, though, like the 91, some of which serve RIDC Park in O'Hara while others service the nearby VA hospital.
So what about the numbers?
The bus route numbers are best explained visually. The numbering system replicates a counter-clockwise dial ranging from 1-99. The number of the route generally relates to the outbound direction starting with Route 1, at the north bank of the Allegheny River and the ending with the 91, which travels (for the most part) along the south bank of the Allegheny River.
With these numbers in mind, you can generally get an understanding of the geographic coverage of the bus route.
The last piece of the puzzle relates to the last digit in the route number.
We now know both the 51, 57 and 58 head in same basic area of the county, but the last number can have meaning as well.
This process has changed over time, so not all of our routes follow the method, but routes were initially numbered so:
Routes ending in a 1 or 6 operate along key corridors.
Routes ending in a 2 or 7 are local routes.
Routes ending in a 3 or 8 are express routes.
Routes ending in a 4 or 9 are cross-city routes that do not terminate Downtown.
This document, dated April 23, 1964, spells out how bus routes were to be numbered. Port Authority was founded on March 1, 1964.
The numbering system has changed significantly over the years, and many have undergone through quite a few iterations. The names of some routes are exactly the same as they were more than 100 years ago, while names of other routes are new within the past few years.
No matter the number of your route, we hope you enjoy riding the bus and find learning about the history as fun as we do.