a new argument for the road lobby

MLewyn's picture

One argument I've seen a lot of in the media runs as follows: "Even though we've increased road space again and again in city after city, we still haven't done enough because road space has not kept up with vehicle miles traveled." What doesn't smell right about this argument?


Induced Demand Means Never Having Enough Highway Miles

I'll take a quick stab at this one: Every time states and regions expand highways -- and use them to serve areas governed by standard, single-use sprawl zoning that requires an auto trip to reach any destination -- the number and length of trips rises, meaning highway miles will never keep pace with vehicle miles travelled.

Who was it who first said, "Widening highways to address congestion is like loosening your belt to cure obesity?"

I believe the quote came

I believe the quote came from Walter Kulash with the Glatting-Jackson firm.

As we pursue this discussion, we should take care not to cast all road construction as anti-urban or counter-productive, remembering that streets are the preeminent public realm. One of the problems with conventional development is not enough of the right kinds of streets and too much dependence on the wrong kinds of streets (highways and freeways). Up until the 1950s or 60s, cities and towns organically expanded their street grids proportional to their geographic expansion. During that time, per household vehicle miles of travel compared to population remained relatively flat. Over the past four or five decades, cities stopped expanding the street grid and started emphasizing the radial/circumferential pattern of higher capacity roads and highways. As a result, growth in household VMTs far outstripped population growth. When those wide, distantly spaced roads and highways intersect, you get massive intersections that are hostile to any living form not confined to a motor vehicle. It seems more sensible to build more streets of the appropriate scale and to return to a mindset that development's responsibility is to expand the grid as it expands the city. I realize this is simplistic, but it conveys the idea that I believe is embedded in New Urbanist principles.

Danny Pleasant, AICP
Charlotte, NC

Excess capacity?

Maybe the over-engineered road network had excess capacity before that's just now being absorbed by the demand induced by it.

MLewyn's picture

Very interesting

Also, it seems to me that this argument leads to absurd results. Even in the places with lots of highway expansions and minimal transit, highway miles haven't kept up with VMT. Does this mean that places like Jacksonville and Tulsa aren't auto-centric ENOUGH?


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