Where Are the Gaps in Your Transit System?

The red areas mark parts of Miami where transit demand is high but service is underwhelming. Map: Center for Neighborhood Technology
The red areas mark parts of Miami where transit demand is high but service is underwhelming. Map: Center for Neighborhood Technology

Where should your city aim to add transit service? The places where more buses and trains will be most useful are areas where lots of people live or work, but there’s not enough service to meet the demand.

A new data tool from the Center for Neighborhood Technology helps pinpoint these locations in cities around the U.S. The “Gap Finder” — an extension of CNT’s All Transit database — overlays demographic data and transit schedule information on maps that highlight where more people would ride transit if service levels were higher.

The transit gaps mapped by CNT are not to be confused with “transit deserts” — areas with no transit at all. Areas with some transit service may still not have nearly enough to adequately serve the people who live or work there, while areas without any service may be so spread out that fixed-route transit won’t do much good.

“The goal is to understand where transit need is being met” and where it’s not, said Zak Accuardi of TransitCenter, which funded CNT’s work.

These gaps in service are highlighted in red on CNT’s map, and areas where transit service is aligned with current demand are in blue. Other areas are too suburban or rural for fixed-route transit services to work well.

Los Angeles
Los Angeles

Some transit gaps reflect the high concentration of people and jobs in relation to transit service levels. That’s the case in Hoboken and Jersey City, the cities directly across the Hudson River from Lower Manhattan.

“These are neighborhoods that are super dense,” said Accuardi. “It’s basically like brownstones. There’s also a lot of jobs in both Hoboken and Jersey City. The volume of transit service that folks there have access to is pretty good compared to the rest of the country. There’s a lot of bus routes operated largely by New Jersey Transit there. For most people in those areas, it’s still really not enough.”

jersey city

CNT quantifies the share of each city’s population living in neighborhoods without adequate transit service. About 42 percent of Miami residents live in areas that qualify as transit gaps, for instance, while in Houston the figure is 55 percent:


The transit gap tool is intended to help local advocates and policy makers think through how they want to improve service. Red areas on the maps should stand out as candidates for increasing the frequency of train and bus service.

For a few reasons, though, the maps shouldn’t be viewed as the last word in assessing transit needs, Accuardi says.

The transit data the maps are based on comes from posted schedules, not real time data. So routes where agencies run a lot of buses but service is slow or unreliable because of traffic congestion won’t get flagged, for instance. Nor do the maps account for barriers to walkability like highways that may make dense areas appear more well-suited for transit than they really are.

“The tool helps to identify areas that are of interest,” said Accuardi. If you want to know where adding bus or train service will help the most people, mapping the transit gaps is an excellent starting point.

4 thoughts on Where Are the Gaps in Your Transit System?

  1. This is going to require some re-reading of their methodology. The first impression of Denver is that improvements would be dramatic if the Colorado PUC were to permit opening of the G-Line commuter rail service that’s been on ice for a year, if some of the most affluent homeowners were provided more service, and if my inner city red zone which already has more service than most areas got even MORE service.

    https://uploads.disquscdn.com/images/07e60c6d8679ec26781ec9ec38f214b3573569819f7f151480aefd84627ab5a8.jpg At present, literally hundreds of riders from the map’s red zone walk to the FREE Mall Ride and FREE MetroRide at Broadway & Colfax (see photo). Service frequency is already at a level that would not attract many more riders away from the free alternative or the extensive bike network in the red zone. Rather, lower fares would be needed to compete with free service. The computer needs to talk with suburban board members and ask them if that idea is acceptable.

  2. Just looking at a few medium-sized rust belt cities in the tool (Minneapolis, Milwaukee, Pittsburgh), it seems to describe areas in the dense walk-sheds around downtown as under served. I’m not sure I would describe these areas as transit gaps, since ped mode share in these areas climb to >50%.

  3. Agreed. Seattle shows up the same way. Of course, in the Seattle case the Red Zone is tilted downhill for the morning commute!

    https://uploads.disquscdn.com/images/891c66b72fa95d2fd219d62b637c6fba6929803daf85e5577f074ef712efc333.jpg Portland doesn’t have a Red Zone, possibly because the Willamette River bridges are in that range on the East Side and transit service has always been good in the only close in West Side areas. There are more peds now than when I snapped these photos, but the areas closest on the East Side include surface lots and commercial activities.

  4. I guess as someone mostly interested in legacy transit cities, I always think your expansions should either (1) increase capacity, and/or (2) increase operating efficiencies. Coverage to underserved areas is secondary. Look where capacity is limited and where you can increase operating efficiencies. Organization before electronics before concrete.

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