Access to employment for households without a car is set by the transport network. What matters is not distance but how many jobs are reachable within an acceptable travel time.
Reachability is the operative measure
Planners increasingly assess networks by counting jobs reachable within a given time, which captures the combined effect of routes, frequency and connections.
A short route to a low-employment area serves fewer people than a longer route reaching a large concentration of jobs, so mileage is a poor proxy.
Because the measure is time-based, improving frequency can raise reachable jobs as much as building new infrastructure, and far more quickly.
Frequency functions as coverage
A service every few minutes can be used without consulting a timetable, so waiting time is short and a missed bus is a minor inconvenience.
An hourly service must be planned around, and a missed connection can cost an hour, which makes the route unusable for shifts with fixed start times.
Networks face a direct trade-off between covering more streets infrequently and running fewer routes frequently, and that choice determines who can rely on the service.
Transfers multiply the risk
Journeys requiring a change carry the delay risk of both legs, and where services are infrequent a small delay on the first becomes a long wait for the second.
Timed connections and integrated ticketing reduce the penalty, but they require coordination between routes and sometimes between operators.
Radial networks designed around a centre serve suburb-to-suburb journeys poorly, and much employment growth has occurred in exactly those locations.
Timetables assume a standard working day
Services are usually concentrated around traditional peaks, so early, late and weekend shifts are served thinly or not at all.
Employment in warehousing, care, cleaning and hospitality operates outside those hours, which is when the network offers least.
The result is that some jobs are formally open to applicants who cannot physically reach them at the required times.
Fare structure affects who can use the system
Where fares are charged per boarding, a journey with transfers costs more, so the least direct journeys are also the most expensive.
Capped daily or weekly fares and free transfers remove that penalty, and pre-payment requirements can exclude households without bank accounts.
Funding, governance and fare policy for transit differ substantially by country and city and change with each budget, so local arrangements govern.