Abstract

I argue that wide residential streets in US cities are both a contributor to homelessness and a potential strategy to provide more affordable housing. In residential neighborhoods, subdivision ordinances typically set binding standards for street width, far in excess of what is economically optimal or what private developers and residents would likely prefer. These street width standards are one contributor to high housing costs and supply restrictions, which exacerbate the housing affordability crisis in high-cost cities. Planning for autonomous vehicles highlights the overprovision of streets in urban areas. Because they can evade municipal anti-camping restrictions that restrict the use of streets by unhoused people, autonomous camper vans have the ability to blur the distinction between land for housing and land for streets. I propose two strategies through which excess street space can accommodate housing in a formalized way. First, cities could permit camper van parking on the right-of-way, analogous to liveaboard canal boats that provide housing options in some UK cities. Second, extending private residential lots into the right-of-way would create space for front-yard accessory dwelling units.

Abstract

Problem, research strategy, and findings:
The width of street rights-of-way is normally determined by traffic engineering and urban design conventions, without considering the immense value of the underlying land. In this article, I develop an economic framework that can inform decisions on street width, and I use tax parcel data to quantify the widths, land areas, and land value of streets in 20 of the largest counties in the United States. Residential street rights-of-way in the urbanized portion of these counties average 55 ft wide, far greater than the functional minimum of 16 ft required for access. The land value of residential streets totals $959 billion in the urbanized portion of the 20-county sample. In most counties, subdivision regulations are binding. That is, few developers choose to build streets that are wider than code requirements, implying that softening requirements would mean more land devoted to housing and less to streets. Although I highlighted the potential for narrower street rights-of-way, I did not consider detailed design issues. Nor did I analyze how any windfall from reduced land requirements would be divided among landowners, developers, and house purchasers.

Takeaway for practice:
Particularly in places with high land values and housing costs, reallocating street rights-of-way to housing would increase economic efficiency. In the most expensive county in the data set—Santa Clara (CA)—narrowing the right-of-way to 16 ft would save more than $100,000 per housing unit through reduced land consumption. Where streets have little or no function through traffic, the costs and benefits accrue almost exclusively to neighborhood residents. Thus, planners could reduce or even eliminate street width requirements in subdivision ordinances, leaving developers to make the trade-off between land for streets and land for housing.