How much higher is ridership on 15-minute frequency buses versus 30-minute buses?

Ridership index for 60-minute service: 1.0. 30-minute: 1.6x. 20-minute: 2.3x. 15-minute: 3.1x. 10-minute: 4.4x. 5-minute: 5.8x. Frequency at or above 15 minutes shifts rider behavior from planning (schedule-dependent) to walk-on (frequency-dependent).

What percentage of residents in the largest US cities live near frequent transit?

Measured as a 5-minute walk to a bus, or 10-minute walk to a rail station, running every 15 minutes or better: New York 83.9%. Chicago 66.0%. Philadelphia 48.5%. Los Angeles 28.7%. San Diego 10.6%. Houston 9.3%. Phoenix 6.4%. Dallas 5.6%. Fort Worth 2.0%. San Antonio 0.3%. Frequency is concentrated in cities with pre-car street grids and rail networks.

Why is 15-minute frequency the behavioral threshold?

Riders planning a trip schedule service at 30+ minute intervals. Riders using frequency as transportation (not schedule) need 15 minutes or less, per transit planner Jarrett Walker’s "frequent network" line. Below that threshold, riders walk to the stop without checking a schedule.

What is the relationship between frequent transit and walkability?

Tight correlation. Dense walkable neighborhoods generate the ridership to justify frequent service. Sprawling neighborhoods cannot sustain frequency above 30 minutes. The two reinforce: walkability enables frequency, frequency enables ridership, ridership sustains density.

How much additional service cost does 15-minute frequency require versus 30-minute?

Roughly 2x the service hours (buses, operators, fuel). The constraint is not cost but ridership volume and driver supply. Cities that upgraded existing routes to frequent service, like Seattle in 2014 and Chicago in 2025, did it by reallocating service hours, not by expanding budgets.

Frequent transit access in America's 10 largest cities

A bus that comes every 15 minutes is treated by riders as a different mode of transport than one that comes every 30. In San Antonio, the 7th largest US city, 0.3% of residents live near frequent transit. In New York, 84%.

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