We’re All Trying to Get Somewhere
Frequency Maps Should Show a Rider’s Perspective
Maps tell stories. They describe where we are and guide us to our next destination. Transit maps show how various modes get people to places they want to go. They also can show which places have access to high-frequency service and which do not.
Take this map for example. It’s one of several from the Maryland Transit Administration (MTA) — part of a presentation to the Regional Transit Plan Commission, a group helping MTA draft a regional transit plan for the next 25 years.
The series of maps attempts to show the level of frequency of transit service — how often buses and trains run — in Baltimore. This one looks at weeknights from 10–11 p.m.
Frequency of transit service matters a great deal to riders. Noted transportation expert and urban planner Christof Spieler says riders value frequency above all else.
He writes in Trains, Buses, People — An Opinionated Atlas of U.S. Transit:
“How frequently a transit route operates makes the difference between a rider being able to depend on transit to be there when they need it, and a rider needing to plan their life around transit.”
This MTA map looks pretty straightforward.
The green areas have low frequency, the yellow ones have moderate frequency, and the red areas have transit arriving every 15 minutes or better. We’ll call the red areas high-frequency.
Intuitively, someone looking at this map would conclude that Baltimore’s downtown and midtown areas have robust late-night frequency between 10 and 11pm, right?
But if you ride public transportation in Baltimore, you know better. Baltimore doesn’t have much frequent late night service.
It turns out, frequency can mean different things depending on your point of view. What this map apparently shows is the effective frequency of all public transportation systems taken together. Read: some transit vehicle — metro car, light rail train, bus, Circulator or whatever — is coming every 15 minutes or better in the red areas of this visualization.
To put it another way, if I’m standing at the Convention Center Light Rail Stop — the site of the recent sinkhole — between 10 and 11 p.m. some bus or train traveling in any direction is scheduled to pass by me every 15 minutes. At least in theory.
If you as a rider have no particular destination and are happy to jump on any bus and go wherever, this definition of “frequency” makes sense. But most riders have a destination.
Additionally, that “15 minutes or better” in this case doesn’t mean that the individual bus and train routes actually come that often. Indeed, if you look at the individual higher-frequency routes in Baltimore, only the Metro and Light Rail have anywhere near that level of scheduled service — that is when they are operating at full capacity.
In truth, only one bus route in Baltimore actually comes close to 15 minutes or better service between 10 and 11 p.m. on weeknights — and that’s only for half the route — the other half, a branch, runs closer to once an hour.
The most frequent buses show up in the 20-30 minute plus range — unless you are traveling from the city to the county — in which case you’re likely to be waiting much longer.
But MTA’s map doesn’t tell us any of this because it doesn’t describe public transportation the way riders actually use it. It does not look at transportation from a rider’s perspective— but rather a planner’s perspective.
No one who rides public transportation rides “all” the buses and trains. No one boards any bus or train that happens to come along without regard for where it might be going. All riders are trying to get somewhere. They want to know how frequently a bus or train will come to take them there.
A map like this one doesn’t accurately show frequency as riders define it.
Counting any transit vehicle that happens to pass regardless of the passenger’s destination misleads the viewer into thinking that service is much more frequent and plentiful than it really is.
The Transportation Alliance shared a draft of this post with the MTA. Deputy Administrator and Chief Planning, Programming and Engineering Officer Holly Arnold replied to acknowledge the concern we raised and provide background on why they chose that particular map to include in the slide deck they used at the Regional Transit Plan Commission meeting. She expressed the challenge of distilling many types of analysis done for the plan into a single presentation for a meeting, and explained that the map in question summarizes many types of existing service. Holly Arnold offered to answer an further questions the Commissioners may have at the next Commission meeting.
We remain concerned that people seeing the map come away with an impression of riders in Baltimore enjoying access to high frequency transit service that does not reflect what riders actually experience. Since understanding the existing conditions as clearly as possible is critical to deciding the types of improvements to prioritize over the next 25 years we ask for the MTA’s help in clarifying for the commissioners what the map does and does not say.
