Thursday, January 13th, 2011

Yes, We Do Need to Build More Roads

When I started this blog I promised to call them like I see them, and not adhere to any particular dogma or policy blindly. In this case, while I know many won’t agree, in my latest piece over at New Geography I argue that Yes, We Do Need to Build More Roads.

The root of this is demographic, as the following chart shows, comparing city population (a proxy for transit friendly areas) versus just the population growth in the US in the last 10 years, a notably slow decade of growth at that.

And there’s 90 million more where that came from projected in the next 40 years. The numbers just don’t add up. I’m all in favor of more dense urban neighborhoods, more transit investments, and even “road diets” where it makes sense. But the reality is that even if we expand roads at a slower rate than population growth, we’ve still got to build.

By the way, that doesn’t apply in slow or negative growth regions like Detroit. The last thing they need is more infrastructure they can’t maintain. But that’s a story for another day.

Topics: Transportation

8 Responses to “Yes, We Do Need to Build More Roads”

  1. 3rdDegreeBurns says:

    Interesting topic. I think it is easy to get caught up in the negative aspects of auto-mobility and forget that much of our nation’s relative prosperity is utterly dependent on our roadway infrastructure.

    However, your thinking needs more development. Are you suggesting that freeway widening projects (such as the ones you cite in Indiana) are needed? If so, what transportation problems do you think they will improve? Do you think we will need entirely new freeways, or just to widen existing ones? What about new or widened arterial roads? The implications of each of these policies are very different and so are the costs.

    You mention the subject of congestion in your post, implying that impending population growth will swamp roads with new levels of congestion that we will be unable to deal with. However, congestion is an unavoidable aspect of roads in our society. In fact, as Anthony Downs of the Brookings Institution has suggested, it may be the only mechanism by which free roads are “priced.” Ironically, congestion’s contribution to overall travel times is part of what enables a city to exist in the first place: if there were no restrictions on the time it took to access destinations, there would be less values in agglomeration.

    I agree with you that we will need to build more roads. However, what form these roads take and where they are built are matters of extreme importance. However, if we want to encourage more compact development we will need to become more comfortable with roadway congestion. In areas that we want to densify, I don’t think we should be widening freeways, instead I would argue to redirect our efforts to providing more diverse transportation options. However, if you are referring to intermetropolitain travel through low-density environments, roadway capacity expansion could be exactly what we need to maintain high speeds.

  2. BrianTH says:

    This is not yet a convincing argument for the need for net road-building.

    One potential problem is that some roads may currently be overbuilt. Some of them could have too much capacity, and maybe the very existence of some roads is not, or will no longer be, justifiable (e.g., in rural areas where depopulation is an ongoing trend). It isn’t too hard to imagine that even if we need to build some new roads/capacity in some cases, other increases in road demand can be met with existing capacity, and the new roads/capacity may be subject to offset by eliminating some old roads/capacity. And in fact there could be lots and lots of miles in the latter category–selecting for roads where things like maintenance and patrolling costs exceed the anticipated benefits actually selects for longer roads.

    Another problem is we don’t really know that road demand per capita will remain fixed. That could be true just from shifting population trends, but it could also be true for technological reasons (e.g., automated cars could potentially greatly reduce road demand per capita with no reduction of automobile passenger-miles per capita). Even a moderately-declining road demand per capita function applied across the entire population base could easily outweigh the increase in road demand associated with increasing population, at least for some long period of time.

    None of this is intended as a complete argument. But the bottomline is that modeling the need for net road-building in the future isn’t really going to be as simple as looking at population projections.

  3. DBR96A says:

    I-376 in Pittsburgh is still underbuilt in spite of the regional population loss. The problem is, a pair of tunnels have to be widened, and right of way will need to be purchased at nearly all interchanges, and those two things will make a widening very expensive, which means the U.S. Government won’t fund it, which means the problem goes unresolved. *sigh*

    Maybe I-76 in Philadelphia can be rightfully expanded now that the city is growing again.

  4. Chris Barnett says:

    Brian, the devil is in the details. The population growth in the US was NOT in places with adequate road infrastructure.

    For example, an “underutilized” 4-lane arterial in Center Township, Indianapolis-Marion County can’t provide additional capacity for a choked “overcapacity” 2-lane arterial in suburban Fishers or Noblesville.

    The decision (and town or county funding) to add capacity in Fishers or Noblesville is independent of the decision to subtract capacity in Indianapolis (whether or not both are in the same MPO).

    DBR, the Schuylkill Expressway (I-76) in Philadelphia has the same kind of constraints as I-376 in Pgh: river, riverbluff, RR tracks. Ain’t gonna happen unless they double-deck it.

    And why would anyone drive it, anyway? SEPTA has lots and lots of suburban commuter trains that go to Delaware, Chester, and Montgomery Counties (where the expressway runs). Park it, and ride.

  5. Everett says:

    Yes, we probably need to build some more roads, but I think to a lesser extent than would be conventionally thought. We really need to do more to encourage denser development. Building more roads just punts when we need a touchdown.

  6. flavius says:

    That is an interesting chart. I would be curious to see how population growth compares to new miles of roadway during the same period.

  7. Alon Levy says:

    In the 1890s, you’d have thought the wealth of the US was utterly dependent on trains, and of course the US should keep subsidizing railroads and give them ever-expanding land grants. Well, it turns out that railroads raised US GDP by 1%. If there had been no railroads, the US would’ve built canals and turnpikes instead, which would have been almost as efficient.

    The same is true for roads today. A city that can’t build more roads, like New York or Portland, will soon turn to other means – transit, walking, flex-time, reduced VMT. Overall economic performance is not going to be any worse: Portland has crap job growth and negative economic growth, just like Atlanta, but at least it has clean air and not too much congestion.

    Large cities get nearly all of their congestion from peak travel to a few CBDs and edge cities. It’s precisely this sort of travel where mass transit can have a very high mode share. Even in Los Angeles, whose metro area has a 6% transit share, the transit share jumps to 40% for people who work in downtown LA. On top of this, in high land value situations roads are too space-inefficient; the original freeways were built in an environment where redlining made it really cheap to demolish urban blocks to make room for roads.

  8. VR says:

    The larges unused road capacity in the country is our cars empty back seats.

    Get more people to use fewer vehicles and bang: instant road expansion.

    But instead of building more roads, how about we make it so you can get around without a car?

The Urban State of Mind: Meditations on the City is the first Urbanophile e-book, featuring provocative essays on the key issues facing our cities, including innovation, talent attraction and brain drain, global soft power, sustainability, economic development, and localism. Included are 28 carefully curated essays out of nearly 1,200 posts in the first seven years of the Urbanophile, plus 9 original pieces. It's great for anyone who cares about our cities.

About the Urbanophile


Aaron M. Renn is an opinion-leading urban analyst, consultant, speaker, and writer on a mission to help America’s cities thrive and find sustainable success in the 21st century.

Full Bio


Please email before connecting with me on LinkedIn if we don't already know each other.



Copyright © 2006-2014 Urbanophile, LLC, All Rights Reserved - Click here for copyright information and disclosures