Can We Build Our Way out of Congestion?

The 2007 Urban Mobility Report contends that, in theory, it is possible for regions to build their way out of congestion. In regions where traffic growth exceeded the growth in road capacity by a wide margin, congestion got worse faster than in communities with a smaller gap. In the short run, it appears, you can mitigate congestion by adding capacity, as shown in the chart above. (I’ll defer discussion of the problem of “induced demand” and what happens over the long run when that new capacity enables dysfunctional land use patterns.)

Here’s the problem: Adding new transportation capacity is really expensive! Here’s how the Urban Mobility puts it:

It would be almost impossible to attempt to maintain a constant congestion level with road construction only. Over the past 2 decades, only about 50 percent of the needed mileage was actually added. This means that it would require at least twice the level of current-day road expansion funding to attempt this road construction strategy. An even larger problem would be to find suitable roads that can be widened, or areas where roads can be added, year after year.

As regions urbanize, acquiring the rights of way to expand roadway capacity increases exponentially. And here’s a factor that the study does not mention: As large developing countries like China and India become major consumers of construction materials, they drive the global cost of those materials. The real, inflation-adjusted cost of road building is more expensive than it used to be. As the cost rises, the Return on Investment declines.

What worked in the 1950s — building Interstate highways with inexpensive construction materials and acquiring cheap right of way by running roughshod over the property rights of poor communities — won’t work today. Transportation strategy must adapt to the reality that adding capacity is more expensive than it used to be. Unless we want to tax ourselves into oblivion, we have no choice but to pursue other strategies.

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4 responses to “Can We Build Our Way out of Congestion?”

  1. Anonymous Avatar

    Other strategies such as

    telecommuting/flex hours/ more places correct?


  2. Anonymous Avatar

    This is not new. It has been in the report for years, but the first time I brought it up EMR clobbered me with myth blather.

    Adding new urban capacity is really expensive, and therefore the ROI is not what it used to be. As a result, urban areas are not paying their full locational costs, and they will never be able to afford to.

    But, Atlanta for example had fewer hours lost to congestion, because the Atlanta area expanded greatly. They used more space.

    We have been over the induced demand thing before. If you are going to use the induced demand argument then it also must be applied equally to shifting demand, as to metro. Once that new highway space becomes available, someone will be incduced to use it.

    Anyway, the induced demand argument has been mostly debunked. Yes, there is induced demand, but more accurate studies have found that it is much less that first thought, and much of the apprent effect is actually due to latent demand.

    Yes, you can build your way out of congestion, but the least expensive way to do it is to build someplace else.


  3. Larry Gross Avatar
    Larry Gross

    ….”As a result, urban areas are not paying their full locational costs”

    how do they do that .. if they have the jobs.. and the employees use the urban roads to out-commute to their external jurisdiction homes?

    Would you say it is the urban areas that are not paying… or the employees who take the jobs then commute to the outer jurisdictions?

    WHO is responsible for the infrastructure costs of the roads that folks use to commute from the outer jurisdictions to their urban jobs?

    and when you say the urban areas are not paying their locational costs – WHO do you mean?

    do you mean the folks who live and work in the urban areas?

    … be specific…

  4. Anonymous Avatar

    Let’s just pick one example. If someone is living in a townhouse or apartment that uses all of the available lot, and then parks their car on a public street for free, then they might not be paying their full locational cost. Same for a business that relies on street parking. Maybe they are paying enough in taxes to cover that street use, and it is a moot issue.

    My sense is that transportation should be public and parking should be private. On street parking is a nuisance and a congestion causing hazard. Better we should use the space for bike lanes.

    At some point in time, some official signed a permit for a business that caused the first inklings of congestion, as workers and customers converged on that business. That official made a mistake.

    Where the workers and customers come from or how far it is makes little difference. The business in question could be tours in an African Safari park. When too many people arrive, you have a problem, and it isn’t caused by where they left from.

    Now, repeat that mistake over and over. Eventually you have traffic backed up all the way to F’burg and beyond.

    If that official ws really looking out for those that are already present and conducting business without congestion, then what he should have done is say no.

    He should have bought the space and held it empty, and sent the bill to his constituents. Then, they would be paying their full locational costs. Or, if it was less expensive, he could build more transportation to support the new business, and bill it out the same way, gaining some tax base in addition.

    But he can’t send the bill to someone in another jurisdiction, or blame someone who wants to come the the attraction he created.

    He’s got the money the attraction creates, however. If his attraction is causing problems someplace else, problems which limit his ability to attract more workers and customers, then there is nothing to prevent him from sending money to another jurisdiction to help solve his transportation problem.

    Or else, the business refused would take the money for his land and go someplace else, presumably where there are customers and workers in an uncongested setting.

    Either way, the flow of money would be, from the center out, not the other way around. Since this is not what is happening (except for businesses that do move out, voluntarily) then it is the congested areas that are not paying their full locational costs.

    The suburban areas have already seen this in action, and learned from the urban areas mistake. So, what they do is just say no, you can’t come here. Or, they set the (new) initiation fee so high that no one wants to join the club. What they don’t do is buy up the vacant space they need to protect themselves. They just stick it to the landowner who joined the game under different rules. As a result, they are not paying their full locational costs, either. It is being paid by the guy sitting on vacant land, just as so often proclaimed.


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