Radio Freethinker

Vancouver's Number 1 Skeptical Podcast and Radio Show

Combating Sprawl

Posted by Daniel Gipps on November 5, 2010

On episode 86 of Radio Freethinker we discussed the efficacy of building bigger highways to combat congestion. That debate is fairly straightforward and the evidence quite conclusively demonstrates that over the long term (over 10 years or more) expanding highways does nothing to lower congestion or speed up commuting times, and it comes at great monetary, and arguably social, costs. For more information on that debate, look at the references in the show notes or listen to the episode.

This blog post will focus on the secondary debate of the causes of urban sprawl which lead naturally to some conclusions on how to combat sprawl. I realized after I presented my argument in episode 86 that I did not do enough research into the causes of urban sprawl. Now that I have done my research I will present a non-exhaustive list of natural, and political causes of sprawl.


– Growth of income

– Reduction of transportation costs due to technological improvement

– Rising city populations


– Property taxes ( by incentivizing owner-occupier over owner-renter, and by incentivizing low density )

– Roads and other expenses to allow for cars

– Public transit

– Infrastructure

– Zoning laws, building codes, subdivision regulations

The natural causes are the causes that are not direct effects of government policy. I would argue that any sprawl created by just these forces is not something that needs to be combatted because it represents the natural expansion caused by human motivation, although others could still argue against it on environmental or social grounds.

The political causes are those created directly from laws passed by government. If the goal is to combat urban sprawl, it seems pretty clear that the best method would be to change the political laws. Ultimately, any method that could be successful would either have to involve reducing the political incentives to urban sprawl or by creating incentives for high-density or mixed residential/commercial communities.

While doing research for this topic I came across some interesting information comparing transportation subsidies in the U.S. and Europe. In the U.S. only 25% of Public Transit operating and capital costs are covered by fares. This compares to 60% of road costs covered by gas taxes and user fees. Compare this to Europe where fares cover 50% of public transit costs and gas taxes and other user fees more than cover spending on roads and other driving services. It’s pretty easy to see why European cities are generally denser and why public transportation is utilized more heavily.

Another  city that is often cited as a great example of smart urban growth rather than haphazard sprawl is Portland, Oregon. To limit sprawl, Portland literally has a border where zoning laws change to very low density, and services like sewage, water, telecommunications, police, fire, and schools are greatly limited. Because of this and other policies like a transportation system built around public transportation, Portland is considered one of the greenest cities in the U.S.

Ultimately any policies implemented to combat sprawl or to improve transit need to be based on sound economics and evidence in order to avoid unintended consequences like those we now face from years of constantly building bigger highways.



2 Responses to “Combating Sprawl”

  1. Ian said

    Nice write-up Daniel. Although Vancouver doesn’t really face sprawl (some of its suburb communities do), would you care to write up a bit of policy related to this for Reason Vancouver? Go ahead and fill something out at

  2. Mclean Edwards said

    I remember seeing a few math talks on modeling road flow many years ago. If I recall correctly, building new roads or highways does next to nothing to increase or speed up traffic flow, even in the short term. This is due to the additional intersections that will have to be created to accommodate another road. The only thing that can help in the short term is widening the road, and this benefit is reduced due to lane changing.

    Mathematically, one of the best ways to increase flow (speed and throughput) is to have drivers drive safer and cooperatively (leave space, reduce number of lane changes, proper signaling). As it is, aggressive drivers are like the ‘rats’ in the prisoner’s dilemma, and slowly force everyone else to drive aggressively.

    Enforced or strongly suggested compliance to cooperative driving standards may be a political and scientific possibility in the near future, with centralized in-car GPS monitoring and feedback, automated/assisted driving, ECUs, and Vehicle RFID, but will take great political will to create.

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