Uday Schultz, a.k.a. A320LGA, has been poking around frequency and job access in New York and Boston. The Boston tables are especially enlightening because the commuter rail corridors are clearly distinguished from the subway corridors, and then it is possible to see which mode provides good access and which doesn’t:
Commuter rail lines are in thin black lines, subway and light rail lines are in thick white lines. Buses are not shown but are included in people’s transportation modes. Departure time is treated as fixed – passengers have five randomly selected departure times in the period between 7:30 and 8:30, and access and waiting times are added to in-vehicle travel time. Better job access is in blue, grading through green and yellow into red where job access is the poorest.
Observe that the subway lines are surrounded by much greener census tracts than places farther out. In particular, the tracts around the Red Line, which heads from Downtown Boston to the south-southeast, and the tracts around the Orange Line, heading south-southwest, are a lot greener than areas in between the two lines. The point where the Red Lin appears to branch is an orange census tract, but that area has no station, and where the stations are, the tracts are a lot greener, underscoring the importance of the subway for job access. The Red Line then crosses into Cambridge, where the tracts are green-blue thanks to the concentration of jobs in that area, but again, the northwestern tail of the line is visibly green, while the northern end of the Orange Line is still yellow while farther-out regions are red.
Unfortunately, commuter rail mostly does not have the same effect, even at rush hour, when frequency is more reasonable than off-peak. There is some yellow around Readville, the rail junction station in the far south of the depicted area, where peak frequency is around 20-25 minutes, before dropping to worse than hourly midday, but by and large the commuter lines do not generate noticeably greener areas around their stations. The difference between the Red Line and the Fitchburg Line to the Northwest is the starkest, but it is not the only place. Where we do see more green around train stations, such as the tail of the Needham Line southwest of the end of the Orange Line, it’s often bus service connecting to the subway or express buses to Downtown Boston, rather than commuter rail service.
The Fairmount Line
The worst case seen on the map is that of the Fairmount Line, extending south of Downtown Boston between the Red and Orange Lines, terminating at Readville. It has poor service both peak and off-peak; when the MBTA recently announced that it would move to an all-day clockface schedule to improve off-peak headways, it gave the Fairmount Line 45-minute frequency all day, which is neither viable for urban trips nor clockface.
On the map, we can see how there is visible yellow and green on the Orange and Red Lines, but not so much along the Fairmount Line. Even at rush hour, job access there is not on a par with what the more frequent subway provides. Nor is the Fairmount Line good for providing access to the jobs most typical of the needs of the working-class neighborhoods it passes through:
The color scheme is relative, so blue is better than red, but the absolute numbers differ. With this restriction, Cambridge is still green-blue – it is full of middle-class jobs but also working-class ones. And the Fairmount Line remains noticeably redder than both the Red and Orange Lines, because the frequency is so low that passengers wait too long for the trip to remain under the 45-minute line.
Captive riders are not captive to your line
American transit planners like to differentiate between choice riders, who can drive if public transportation isn’t good enough, and captive riders, who can’t. It’s a bad distinction and Jarrett Walker for example has been criticizing it for at least 11 years. Regardless, captive riders who have no alternative to public transportation do have an alternative to one specific line. If the Fairmount Line is bad, they will ride buses and have hour-long commutes, or walk long distances to the subway for same. As a result, the ridership of the Fairmount Line is very weak.
Between the idea of captive riders and the idea that commuter rail is only for the suburban middle class and isn’t really public transit, it’s not surprising why the people who manage the MBTA underserve the line. They hesitate to expand commuter rail beyond its suburban commuter niche, to the point of thinking 45-minute frequencies are good service. Nor do they think in terms of alternatives – captive riders are not supposed to have them, so the idea that they can just ride something else is not usually part of how American transit planners do business analysis.
With such hesitation, they rely on government-by-pilot-program to test new ideas. But all pilots are doomed to failure when the Orange Line runs every 6 minutes and the Red Line’s Ashmont branch every 9. Small increases in service do not lead to high ridership, because riders can still more easily ride a bus or the subway, and this will not change until Fairmount Line frequency is raised to near-urban levels, at worst every 20 minutes, more likely every 7.5 or every 10. Until this happens, commutes in Mattapan and the western parts of Dorchester will remain very long and job access will be poor.