The signature metric on MetroTrack is a job-access score: for a given place, how many jobs can a rider reach within a fixed travel-time budget using transit and walking. It compresses a lot of geography into one comparable number, which is exactly why it’s worth being precise about what it does and doesn’t say.
The ingredients
A job-access score is a spatial join of three layers:
- Where jobs are — employment counts by small geographic area.
- Where people can get to — travel-time areas (isochrones) computed from transit schedules plus a short walk at each end.
- The budget — a fixed cutoff, commonly 45 minutes, that defines “reachable.”
Multiply reachable areas by the jobs inside them, sum, and you have the score. Change the budget and the number moves — a 30-minute score and a 60-minute score answer different questions.
What it captures well
- Network effect, not just proximity. Living near a rail line only helps if that line goes where the jobs are.
- Comparisons across places under identical assumptions.
- Change over time as service is added or cut.
What it deliberately omits
A single number hides real texture, and honesty means naming the gaps:
- It counts jobs reachable, not jobs you’d want or qualify for.
- Schedule-based travel times assume the trip goes as timetabled; real-world reliability is a separate measurement.
- Off-peak and late-night access can differ sharply from the peak figure.
A good score tells you the door is open. It doesn’t promise the trip is pleasant.
When this metric ships, every score on the site will show its travel-time budget, the schedule date it was computed from, and a link to the underlying method — so the number is legible, not magic.