Transportation Affordability in North Carolina’s Research Triangle

We begin our analysis of transportation affordability by examining the Triangle metro area.  Like many metros in North Carolina, the Triangle is very sprawling.  A recent report ranked Raleigh-Cary as the 67th most sprawling metro (out of 221 analyzed), while Durham-Chapel Hill placed 31st.*  Both have little mixing between residential areas and job centers – meaning that residents have to drive longer distances to employment.  This, in turn, drives up transportation costs for residents.


Click the map above to go to an interactive version.

A sprawling metro

Unlike most metro areas (Charlotte, for example), the Triangle doesn’t have a single employment center, like a downtown.  Instead, jobs in the Triangle are spread across the three main cities – Raleigh, Durham, and Chapel Hill – in addition to Research Triangle Park (RTP).  This spread is seen in the first map:  the three downtowns cities and RTP stand out.

Retail jobs are similarly spread throughout the Triangle, and also cluster in the three main cities.  In addition, concentrations of retail jobs are found along the US 15-501 corridor between Durham and Chapel Hill and near Southpoint Mall in southern Durham County.

On the one hand, spreading jobs throughout a metro area could reduce transportation costs, as jobs are accessible to more residents.  However, because the Triangle ranks poorly on mixing between housing and jobs, most residents still face long commutes.

Transportation costs for low-income families

Relatively speaking, transportation affordability (per LAI data) is roughly the same for the three household types examined:  an individual in poverty, a low-income single parent with two children, and a working-class household of three.  Neighborhoods with the lowest transportation costs are located within the city limits of Raleigh, Durham, and Chapel Hill.  As one moves out further from these cities, transportation costs increase – though they are slightly lower along Interstate 40 between Raleigh and Durham (near Research Triangle Park).

Outside these cities, households dedicate more income on transportation.  Not only are these areas farther from job centers, but they have little (or no) transit service.  For the two poorest household types – a person in poverty and single parents with children – nearly the entire western portion of the Triangle is very high-cost.  These areas are slightly more affordable for working-class household, who rely less on transit.

When looking at the maps, though, note that each has a different legend.  For a person in poverty, the lightest greens (that is, the most affordable) are where they would spend 40% of their income on transportation.**  For a working-class household, though, the lightest shades are where it would spend 20% on transportation.  When we apply the working-class household legend to the household in poverty, the entire map is dark green.

Sprawl in the Triangle leads to lengthy commutes for many workers.

Affordable housing and transportation

Affordable housing can only truly be affordable if its residents can easily access jobs, services, and other necessities.  In the Triangle, low-income residents pay the least for transportation in the denser parts of Raleigh, Durham, and Chapel Hill.  The area between these cities – near Research Triangle Park and the suburbs of Cary and Morrisville – has slightly higher transportation costs.  Outlying counties have the greatest transportation costs.

In a future post, we’ll combine the data on transportation affordability and income inequality to find areas best suited for affordable housing.  In it, we argue that affordable housing should be targeted to neighborhoods that lack low-income housing but enjoy greater lower transportation costs.  Doing so will avoid concentrating of low-income residents in certain neighborhoods while allowing them to commute to jobs and other life necessities.

*The Triangle comprises two separate Metropolitan Statistical Areas (MSA), which are defined by the Census:  Raleigh-Cary and Durham Chapel Hill.  In this post (as in the last one about the Triangle), we analyze both at the same time.

**For comparison, the average US household spends about 14% of their income on transportation.

2 thoughts on “Transportation Affordability in North Carolina’s Research Triangle

  1. Pingback: Transportation Affordability in Metro Charlotte | Urban 2 Point 0

  2. Pingback: Transportation Affordability in North Carolina’s Triad Region | Urban 2 Point 0

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