Transit Deserts in Fort Worth
Transit deserts are areas where there is high demand for public transportation, but a low supply of public transportation. Calculating transit deserts can be done by measuring the transit demand in a city, measuring the transit supply, and then subtracting the demand from the supply to find the "gap" in transit service. This gap is the transit desert.
In this example, transit deserts were calculated in Fort Worth, Texas using the method described above. Both supply and demand were measured at the block group level. Transit demand is measured by calculating the "transit dependent population" within each block group. Data is collected from the Census (ACS 2012) for this. In order to measure the transit dependent population, the vehicles available must be subtracted from household drivers. The number of household drivers is the population age 16 and over minus people living in group quarters. Once the transit dependent population is calculated it is possible to find the percentage of the population that is transit dependent in each block group by dividing the transit dependent population by the total population. This is shown in the transit dependency map. Then, the transit dependent population within each block groups is divided by the acres in each block group to find the transit dependent population per acre. A z-score is calculated based on this that will eventually be subtracted from the supply z-score to identify the "transit deserts."
Measuring transit supply is also done at the block group level. Seven characteristics were taken into consideration for measuring the transit supply in Fort Worth; intersection density, number of transit stops, number of transit trips (within a 24 hour period), number of bus routes, total length of sidewalks, total length of bike routes, and total length of low-speed roads. Characteristics relating to the actual transit service, such as number of bus lines and frequency of service, as well as characteristics relating to transit access, such as intersection density and sidewalk lengths, were used so as to address both the service and access to the service. Each of these characteristics was measured in every block group and then divided by the number of acres in each block group to find a per acre measurement of each characteristic. Z scores were calculated for each of these seven characteristics and then aggregated to find an overall score for transit supply in each block group.
Once the z scores for supply and demand are calculated, the score for demand is subtracted from the score for supply to measure the gap in transit service, if there is one. Three maps were generated to visually display the data more clearly.
Transit supply in Fort Worth is primarily focused around downtown and at a node in the far northern part of the city. One can also see an arm of denser transit supply extending from downtown to the southwest along Camp Bowie Boulevard. Transit dependent populations are scattered throughout the city, but are very much absent from downtown and the west side of town south of the West Fork of the Trinity River. There is a large, linear area to the east of downtown between Interstate 30 and 121 where there is a relatively large percentage of transit dependent people. Other areas with high percentages of transit dependent people are scattered towards the edge of the city limits, especially in the far northern part of the city, where the city has expanded in recent years.
Transit gaps in Fort Worth are scattered throughout the city. While there are a few relatively close in, most are not located in the central part of the city. The area near TCU (Texas Christian University) is shown as being a transit desert. The area is served by transit and relatively close in, but the presence of students living in high density makes the demand for public transportation much greater than the supply. Downtown and the area immediately to the south and west have a surplus in transit supply. These areas have also been built up significantly in the past few years. Other significant areas where there are large gaps between supply and demand are in the far western part of the city near the Western Hills area and in the far southern South Hills area. Ridgmar also has a relatively high gap. The lack of transit service in that area might be attributed to the very irregular street network. The block groups with the highest and lowest gaps in transit are shown in the tables below.
By identifying transit deserts in Fort Worth, existing and future transit services can be improved. Demonstrating where there are large gaps between supply and demand is a step towards a more efficient and effective transportation network.