Congestion and Patterns of Growth

The costs of "growing up, not out" are greatly increased congestion and pollution and reduced mobility.

The average Portland-area auto commuter spends at least 30 hours per year tied up in traffic. According to Metro, its 2040 plan will more than quadruple this, which will make Portland more congested than any other city, including Los Angeles, is today.

The 2040 plan is based on the principle of "growing up, not out." To minimize sprawl, Metro wants to increase population densities inside the urban-growth boundary. Metro planners suggest that higher densities will make it easier for people to walk, bicycle, or ride transit to work. Metro's critics say that higher densities will actually make Portland more congested than it needs to be.

To understand the relationship between growth patterns and congestion, it is important to understand commuter behavior and why we have congestion in the first place.

The Cause of Congestion

Congestion is often blamed on "too many people." But congestion is not simply a function of people, it has to do with a variety of transportation and land-use patterns. According to the Texas Transportation Institute, which has monitored congestion in 50 cities for over a decade, congestion in Seattle is much worse than in the larger cities of Chicago, Philadelphia, Detroit, San Diego, or Baltimore.

Congestion is also sometimes blamed on freeways. People say that "freeways just get filled up as soon as they are built." When that happens--and it doesn't always happen--it is because the freeways are simply better than the routes people had previously been taking.

Finally, congestion is often blamed on sprawl. When a city covers a larger area, people have further to go to get to many places. This supposedly means people have to drive more, thus leading to more congestion. In fact, as we will see, exactly the opposite is true.

The real source of congestion is in how people pay for roads. Instead of paying for the roads they actually use, they pay for all roads when they buy gasoline. This makes sense so long as most roads cost about the same amount to build and provide roughly the same level of service.

These conditions may have been true decades ago when all roads were exactly two lanes wide. But today urban commuters have a wide range of options:

Figure one: A 60-mile-per-hour highway may cost fifty times as much as a 20-mile-per-hour street, and it provides three times the benefits. Yet when roads are paid through gas taxes, users pay the same for both.

Note that, although the cost of each level of service increases dramatically over the previous level, the percentage increase in speed gets smaller and smaller. Since people pay about the same whether they drive on a freeway or a two-lane street, they choose the freeway whenever they can. People might have to pay even less gasoline tax on the freeways since less stop-and-go traffic translates to better fuel economy.

Paying for roads through a gas tax is the same as getting a free pound of beef when you buy a quart of milk. If the milk costs the same whether the beef consists of hamburger or filet mignon, then most people will choose the steak. Any supermarket that sold food this way would end up with a surplus of hamburger and a shortage of steak.

This explains why newly built freeways seem to instantly get crowded: Since the freeways provide better service yet cost no more (or even less) to use than other roads, people switch from the other roads to the freeways.

A similar problem is found when considering the time of day when people drive. Urban highways are most crowded during evening rush hours (when 60 percent of the traffic is not commuters), followed by morning rush hours (when 40 percent is not commuters), followed by midday, then evening, and finally late night. Demand for telephone service follows the same pattern, and most phone companies charge more for daytime long-distance service than for evening, and charge the least for late-night service.

But highway users pay the same gas taxes whether they drive at 5 pm or 5 am. Even tollways don't solve this problem, as most of them charge the same at all times of the day. So the huge number of noncommuters who drive at rush hour have little reason to drive at a different time of day.

Governor John Kitzhaber has proposed to fund highways with a per-mile tax paid by auto drivers. But this wouldn't solve any of the problems any better than a gas tax, because the tax would be the same whether people drive on a freeway during rush hour or on a two-lane street at midnight.

In a supermarket, prices act as signals informing consumers of the relative scarcity of various goods such as hamburger or steak. Gasoline taxes and per-mile taxes fail to provide such signals. Attempts to "solve" this problem with federal funding to mass transit are doomed to failure because subsidized buses or rail lines don't change the price signals that encourage people to clog up the freeways.

Commuting Behavior

Since congestion is caused by underpriced freeways and highways, people respond to the congestion in other ways. For several decades, the Census Bureau has kept track of how much time people spend commuting to work. The data show that, no matter where people live, they tend to spend an average of about 22 minutes in their commute. This rule has held true for as long as the Census Bureau has kept track of this.

When cities get more congested, people tend to move closer to their work to keep their average commute times around 22 minutes. Employers may also relocate to be closer to their workers. One way they can do this is to move from the city centers to the suburbs. The "flight" of jobs from city centers has been a direct response to congestion in those city centers.

Washington Post writer Joel Garreau found that employers often concentrated in suburban areas that he called "edge cities." When those edge cities get congested, some employers move further out to create new edge cities. The Beaverton-Washington Square area is an edge city outside of Portland, and Hillsboro is becoming an edge city outside of Beaverton.

Given that congestion takes place because highways are crowded, one way to relieve congestion without changing highway funding is to build more highways. But urban residents oppose more highways in the center cities. Portlanders successfully stopped construction of the Mt. Hood Freeway, in southeast Portland, in the 1970s.

The alternative to building new highways in the center cities is to build them in the suburbs where little or no preexisting development is found. If this can be done, then "sprawl"--the geographic growth of urban areas--is not only a natural response to congestion, it is politically one of the easiest ways to relieve congestion.

Metro's 2040 Plan

Metro planners, however, want to minimize any sprawl beyond the current urban-growth boundary. Instead of building more highways at the edge of the city, they propose to contain a projected 80 percent increase in population within an growth boundary that is only about 5 or 6 percent larger than today. This means higher density developments such as apartments, row houses, and homes on smaller lots. Planners call this "growing up, not out."

Higher densities may decrease the share of people using autos. But the decrease auto use will be smaller than the increase in density. In Portland, Metro predicts that a 75-percent increase in density will result in a decrease in the auto's share of traffic by only 5 percent.

That translates to a 70-percent increase in the number of cars on the road at any given time. To serve those additional cars, Metro proposes to build just 13 percent more lane-miles of roads. No wonder Metro projects a quadrupling of congestion!

Figure two: Metro expects a 75-percent increase in population and a 70-percent increase in traffic by 2040, but plans to build only 13 percent more lane-miles of roads. The result will be a near-quadrupling of the number of miles of congested roads.

Metro's plan is oriented around "pedestrian-friendly design" and "transit-oriented developments. But in making the Portland area "friendly" for the 10 percent of people who will walk or ride transit, Metro will make the city as hostile as possible for the 90 percent of people who, by Metro's own calculations, will still use cars.

With congestion will come more pollution, since cars produce more air pollution in stop-and-go traffic than on uncongested roads. Metro estimates that its plan will produce 10 percent more smog.

In considering alternatives to its plan, Metro estimated the effects of increasing or even eliminating the urban-growth boundary. But all of Metro's alternatives called for building even fewer new lane-miles of roads in the Portland region than its plan, resulting in even more congestion. Metro then falsely claimed that the lower congestion from its plan was a result of higher densities, not from the added roads that its plan would build.

We don't need to pave all of Oregon to reduce congestion. But Metro's plan makes congestion a goal rather than something to be avoided. Congestion, says Metro, "signals positive urban development."

If you want to solve Portland's congestion problems, not make them worse, then contact your city councillors and Metro councillors and tell them to stop the Metro 2040 plan now--before it's too late.


Peter Gordon & Harry Richardson, "Are Compact Cities a Desirable Planning Goal?" July 1995 ("sprawl" as a response to congestion).

Metro, Region 2040 Recommended Alternative Technical Appendix, September 1994 (Predictions of future traffic, congestion, etc.).

Alan Pisarski, Commuting in America, 1987 (commuting behavior).

Texas Transportation Institute, Trends in Urban Roadway Congestion, 1994 (congestion in 50 U.S. cities).

This fact sheet was prepared by the Thoreau Institute for ORTEM, a citizens' group opposed to the Metro 2040 plan. Fact sheets are available on a variety of other topics, including congestion, light rail, and open space. If you have any questions or would like hard copies of this fact sheet, please call or write the Thoreau Institute, 14417 S.E. Laurie, Oak Grove, Oregon 97267, 503-652-7049, or email

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