The Fuse

Land-Use Zoning and Fuel Consumption: Portland’s Urban Growth Boundaries

by Hart Schwartz | February 28, 2018

Land-use zoning is a quiet, hidden factor that can exercise a profound long-term impact on fuel consumption. It defines political contests over land-use choices and thus helps set context for whether metro geography will be low-density and auto-friendly, or high-density, transit-friendly, and walkable. Portland, Oregon presents an instructive case study regarding the connections between zoning, land-use, and fuel consumption.

Portland’s urban growth boundaries have contributed to higher transit ridership levels and lower vehicle miles traveled (VMT) than other metro areas of similar population.

Unique among American cities, Portland’s urban growth boundaries (UGBs), mandated by the state of Oregon since Senate Bill 100 of 1973, regulate the expansion of developable land in the suburbs and render Portland the only major metropolitan area in the United States for which the state has the final say on land-use. In conjunction with a major investment in transit infrastructure, the UGBs have contributed to higher transit ridership levels and lower vehicle-miles-traveled (VMT) than other metro areas of similar population.

Why has Portland developed in such a unique manner? Portland’s urban growth boundaries grew out of a statewide concern with a comprehensive variety of issues, including but not limited to urban development, and including but not limited to Portland. Could this situation happen elsewhere?  Briefly reviewing the legislative background of Bill 100 can put this into clearer perspective. The following info-graphic summarizes legislative events leading to passage of Bill 100, as well as subsequent Portland transit history, against the background of metro population growth.

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In the 1940s, dramatic increases in Portland’s suburban population, which had doubled several times between 1900 and 1940, sparked widespread concern about disorderly growth. Perceived negative impacts included rapid farmland conversion into suburbs; environmental disruption; and excessive infrastructure costs. The state took several actions to expand its authority, including authorization of counties to develop land-use planning regulations in 1947, and tax code adjustments throughout the 1960s to incentivize farm use over suburban development. An initial, less complete attempt at a comprehensive statewide land use bill, Senate Bill 10, passed in 1969.

In 1973, spearheaded by Republican governor Tom McCall, Senate Bill 100 enacted the urban growth boundaries, by expanding and deepening 1969’s Bill 10. Bill 100 transformed the recommended framework of Bill 10 into an obligatory mandate. Fourteen “statewide planning goals” (later expanded to 19) formed the core of Bill 100. These goals addressed a comprehensive range of issues, such as Agricultural Land (#3), Forest Lands (#4), or Air, Water, and Land Resources Quality (#6). The Urban Growth Boundaries were contained in #14, Urbanization. This section specified that all urban areas in Oregon, not just Portland, would need to develop land-use plans to meet binding standards. Senate Bill 100 created a new government agency, the Land Conservation and Development Commission (LCDC), to implement the land-use planning goals.

What makes Portland so different? State-level, comprehensive approach

This brief history underscores the statewide, comprehensive basis of Portland’s urban growth boundaries. The regime created by Bill 100 seeks to balance impacts in different regions of the state, wrapping interrelated policy goals into a comprehensive package for all types of land in Oregon (cities, suburbs, and rural). No other state has passed a similar bill. What accounts for Oregon’s ability to not only pass Bill 100, but also maintain it in force for many ensuing decades? Did political interests counter-balance in a manner unique to Oregon and unattainable elsewhere? For instance, overwhelmingly rural states, such as Wyoming or Idaho, may lack urban areas large enough for unrestricted suburban development to cause serious enough problems for the state government to feel a need to step in. On the other hand, majority-urban states, such as New York or Massachusetts, may not have enough farmland for farmers to constitute a large enough pressure group to effectively counter-weigh urban interests.

Impact: High Transit Ridership and Low VMT

Portland’s UGBs have likely played a key role in its high level of transit ridership. Limiting developable land encouraged denser, more transit-friendly suburbs

Looking at transportation statistics can help to identify the concrete impact of Portland’s urban growth boundaries. As shown in the following graphs, Portland has the highest transit ridership and third-lowest daily VMT of comparable population metro areas (two to three million population).

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Portland’s urban growth boundaries have likely played a key role in its high level of transit ridership. Limiting developable land seems to have encouraged denser, more transit-friendly suburbs: Many places in the Portland suburbs have density levels of approximately 4,000 people per square mile, a very high level for suburbs built during the automobile and highway era of recent decades. High suburban density facilitates transit ridership by addressing the “double last-mile problem.” That is, transit ridership requires density at both trip origin and trip destination. The greater the number of people living less than a twenty-minute walk to a rail station, the greater the number of possible trip origins and potential system riders. Dense suburbs create a larger pool of riders.

Portland shows the lowest “drive alone” share and the highest transit, bike, and walk shares, among metro areas in its population class.

Portland’s lower level of VMT likely results from its high level of transit use as well as its higher level of walkability. While hard to measure directly, mode choice can be partially seen in journey-to-work statistics available from the Census Bureau. In these statistics, Portland shows the lowest “drive alone” share and the highest transit, bike, and walk shares, among metro areas in its population class.

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On the other hand, at 71 percent of commuters driving to work alone, it seems that there’s still a significant way to go in terms of reducing driving. Curiously, despite the high transit ridership and low daily VMT statistics, Portland metro has one of the highest rates of household vehicle ownership for metro areas of its population class.

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Lessons Learned: Land zoning and fuel consumption?

One stark contrast to Portland is Houston, Texas, the only U.S. metropolitan area with no zoning laws at all.

The transportation statistics by and large seem to show that something materially different has occurred in Portland. In terms of determining how much the urban growth boundaries are responsible for, a comparison might be helpful. One stark contrast to Portland is Houston, Texas, the only U.S. metropolitan area with no zoning laws at all. Houston has developed in an extremely highway-friendly configuration, constrained only by its residents’ ability to purchase automobiles; willingness to drive long distances; price of available land for development; and the government’s financial capacity to build highways. In Houston, land has become built in such a far-flung pattern, with many high-speed expressways, that even the service roads for urban Interstates are used for regular automotive travel at speeds over 50 mph.

Awareness of zoning law’s quiet impact, as exemplified in Portland, Houston, and elsewhere, can lead to clearer understanding of a path forward. Future articles will explore the impact of other aspects of zoning on transportation and fuel consumption.

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