Less than two months after President Donald Trump pledged in his State of the Union Address to “rebuild our crumbling infrastructure,” prospects look dim. The Trump administration is asking Congress for ideas about how to fund trillions of dollars in improvements that experts say are needed. Some Democrats want to reverse newly enacted tax cuts to fund repairs – an unlikely strategy as long as Republicans control Congress.
Deciding how to fund investments on this scale is primarily a job for elected officials, but research can help set priorities. Our current work focuses on transit, which is critical to health and economic development, since it connects people with jobs, services and recreational opportunities.
Along with other colleagues at the Urban Information Lab at the University of Texas, we have developed a website showing which areas in major U.S. cities do not have sufficient alternatives to car ownership. Using these methods, we have determined that lack of transit access is a widespread problem. In some of the most severely affected cities, 1 in 8 residents lives in what we refer to as transit deserts.
Deserts and oases
Using GIS-based mapping technology, we recently assessed 52 U.S. cities, from large metropolises like New York City and Los Angeles to smaller cities such as Wichita. We systematically analyzed transportation and demand at the block group level – essentially, by neighborhoods. Then we classified block groups as “transit deserts,” with inadequate transportation services compared to demand; “transit oases,” with more transportation services than demand; and areas where transit supply meets demand.
To calculate the supply, we mapped out cities’ transportation systems using publicly available data sets, including General Transit Feed Specification data. GTFS data sets are published by transit service companies and provide detailed information about their transit systems, such as route information, frequency of service and locations of stops.
We calculated demand for transit using American Community Survey data from the U.S. Census Bureau. Transportation demand is difficult to quantify, so we used the number of transit-dependent people in each city as a proxy. A transit-dependent person is someone over the age of 12 who may need access to transportation but cannot or does not drive because he or she is too young, is disabled, is too poor to own a vehicle or chooses not to own a car.
Transportation deserts were present to varying degrees in all 52 cities in our study. In transit desert block groups, on average, about 43 percent of residents were transit dependent. But surprisingly, even in block groups that have enough transit service to meet demand, 38 percent of the population was transit dependent. This tells us that there is broad need for alternatives to individual car ownership.
Urban Information Lab, University of Texas – Austin, CC BY-ND
For example, we found that 22 percent of block groups in San Francisco were transit deserts. This does not mean that transit supply is weak within San Francisco. Rather, transit demand is high because many residents do not own cars or cannot drive, and in some neighborhoods, this demand is not being met.
In contrast, the city of San Jose, California, has a high rate of car ownership and consequently a low rate of transit demand. And the city’s transit supply is relatively good, so we only found 2 percent of block groups that were transit deserts.
Who do transit agencies serve?
Traditional transit planning is primarily focused on easing commute times into central business districts, not on providing adequate transportation within residential areas. Our preliminary analysis showed that lack of transit access was correlated with living in denser areas. For example, in New York City there are transit deserts along the the Upper West and Upper East sides, which are high-density residential areas but do not have enough transit options to meet residents’ needs.