Choosing the Road Less Valued

Are more roads inherently better? In the United States, hundreds of billions of dollars are spent annually on building, expanding, and maintaining roadway systems. What are the calculable benefits of the resources allocated to ongoing roadway expansion?

One would have to measure the roads currently spanning the U.S. and calculate the land value lost in the process. It is not a simple undertaking.

In "Urban Roadway in America: The Amount, Extent, and Value" (Journal of the American Planning Association, Vol. 90, No. 4) Erick Guerra, Gilles Duranton, and Xinyu Ma calculate road dimensions and land value across metropolitan areas in the U.S.

What is the Value?

The authors found that roadways accounted for a fifth to a quarter of all urbanized land in the U.S. — around 6,458 square feet per household. This is equivalent to the total land area of West Virginia and is worth $4.1 trillion.

This is consistent with findings that the construction costs of urban interstate highways are, on average, twice that of the benefits.

Dedicating more land to roadways would likely lead to net losses in social welfare. The authors suggest that removing and narrowing roadways could generate substantial benefits. They calculate that a 10 percent reduction in urban roadways from removing, narrowing, or downgrading roadways would result in an estimated net benefit of $27.8 billion annually.

This does not include the bonus of reducing pollution, greenhouse gas emissions, and traffic fatalities.

The study's predictive models relied on a 10 percent sample of roadway widths from the Highway Performance Monitoring System. The sample was then applied to estimate the rest of the roadway system. The authors matched roadway segments and areas to existing land value estimates and satellite-based measures of urbanized land.

Revised Cost-Benefits

As one of the first studies of its kind, the authors call for more research to better understand roadway space and its value. They argue that it is an essential component of assessing state and federal transportation policy, conducting cost-benefit analyses, and helping local officials understand how their cities, towns, and metropolitan areas compare with others.

Perhaps if officials could see how much money is being lost instead of gained, policies and initiatives could change in favor of more housing, offices, and other land uses.

Future research could rely on data from major phone and map-producing companies, who have sufficient data from cell phone traces to develop detailed models of roadway systems. Vehicle-mounted light detection and ranging (LiDAR) and cameras also provide inputs to develop more accurate models of roadway networks.

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