Wait at the bus stop
Stand at a stop and two questions decide whether you will use transit here: how long until the next one, and how far can it take you? Public transit measures both, the reach of the network and how often it runs.
It is one of the ways of getting around town without a car, one part of overall mobility.
How we work it out
We split the city into squares about 250 metres across and score each one on its own. For a square, we follow the real streets to the nearest stop, not a straight line across the map, and check how often that stop runs. A stop just across a river is as far as the walk to the bridge, not the short hop the map would suggest. People walk further for a train than a bus, so the reach is wider for metro and rail, about a kilometre, than for buses and trams, about half that.
Then we sort every square into three groups and weight them by how many people live there, so the numbers add up to the whole city:
- Frequent. Can walk to a stop that runs at least every ten minutes.
- Less often. A stop within a short walk, but it comes less often.
- None. No stop within a short walk at all.
The 0 to 5 score blends the same two things, how near the service is and how often it runs, into one number. Where a city publishes no real schedule, we don't guess. We mark its transit coverage as partial and say so, instead of showing a low score as if it were certain.
Where the numbers come from
The schedules come straight from the transit agencies that run the service. They publish them in GTFS, the open standard behind the trip planner in most map apps, and we collect those feeds through the Mobility Database, a public catalogue of transit feeds from around the world. Coverage is best where an agency keeps its feed complete and current. See coverage and data tiers.
What it can't tell you
- The feeds show planned service, not today's delay or cancellation.
- It doesn't measure fares or crowding. Good coverage can still be expensive, or packed at rush hour.
- It scores a city's whole network, not the one line you would take.
- A city with no published schedule reads as partial coverage, never as a low score.
See it live
The Public Transit Lab scores cities one at a time, each with its own coverage map and the three numbers side by side. The same three numbers place a city anywhere on the scale:
- Paris: about 9 in 10 residents can walk to frequent service.
- Valence: most have a stop nearby, but it comes less often.
- Béziers: almost none of the city has frequent service.
For the flight out, see airport connectivity. Or look at transit city by city on the explore map.