Accessibility to Transportation Project

This project demonstrates how cities could utilize demographic data, city General Tra c Feed Specification Data (GTFS), and a transit network dataset to determine where new bus routes or transportation lines could be made.

GTFS datasets are publically available transit data that can provide information about a transit system’s stops, routes, and schedules. This data can often be accessed from city websites or public domains such as Transitland or OpenMobilityData. In this project, accessing GTFS data provided the data necessary to map bus stops and generate the bus stops’ service areas.

Once the Salt Lake County bus stops had been mapped, a general service area of the bus stops and transportation lines could be generated. The general service area visualizes the area that public transportation covers.

In order to generate the general service area, a network analysis must be made. A network analysis utilizes data from a network dataset, which is a dataset designed specifically to support data analyses. In the case of transit data, a network dataset would be created as lines (roads), points (junctions, stops), topology, and other attributes. Utilizing a network dataset to complete a service area analysis will keep in consideration both connectivity and impedance (i.e travel costs and speed).

The network dataset used in this project came from the Utah Roads Network Analysis dataset produced by the Utah Geospatial Research Center (UGRC). The service area was measured by calculating the distance accessable to each bus stop within a 10-minute walk.

With an established general service area for the Salt Lake County, a map of the demographics in the county is necessary in determining which areas would benefit most from an expanded bus line. In order to do this, we must first add data to county’s block groups. Block groups are the second smallest geopgrahic measurement used by the United States census, and would be perfect for accurately mapping specific regions most in need of expanded bus routes.

In order to add demographic data into each block group, we must first enrich each block data group. The three di erent variables of demographic data added were population density, no access to vehicles, and poverty

After overlaying each enriched block group over each other, we are now presented with a map that displays a visual representations of demographic data across the county of Salt Lake. We are able to see which areas have the highest population density, poverty, and no access to cars.

As expected of the downtown Salt Lake City area, it is the highest in population density, poverty, and no access to cars. Visualizing data in such a manner is crucial as it allows us to better determine and process which areas are most suitable for an expanded bus route. In the case of this project, regions with higher population densities, poverty, and no access to cars are going to be prioritized when it comes to expanding bus services.

The demographic map must also be matched with the general service area of the transport network to determine which areas are currently not covered, or are not experiencing enough coverage from existing bus lines.

Just from the mere overlay, we can see that the service area of the bus transportation network already covers the majority of the county. With this observation, one would reasonably be able to deduce that Salt Lake County does provide a bus route that covers most of its county.

However, after creating a masking overlay that shows the remaining census block groups uncovered by the bus line service area, we can see some cities in the southern region of the county are still uncovered. As we can see on the map, a large portion of Herriman city and many block groups in between Herriman and Riverton are largely untouched by the currently established bus lines.

The result of this project does hold some credibility in the sense that these communities have heavily urbanized and rapidly expanded in population size in recent years. Herriman especially has seen tremendous growth in recent years, with the U.S. Census Bureau showing a population growth of over 10,000 residents from 2010-2019. The area is also growing at a 3.33% annually and since 2020, the population has increased by 10.34%. The reason for lack of coverage by bus transit lines might be explained by the area’s massive urbanization, population growth, and overall economic growth since the major bus lines had been established.