Thoughts about the Federal Congestion Mitigation and Air Quality Improvement (CMAQ) Program

By Dom Nozzi

Early in 1999, the director of a county environmental protection office asked about a program known as

Congestion Mitigation and Air Quality Improvement (CMAQ). This is a federal program that was implemented to support surface transportation projects and other related efforts that contribute air quality improvements and provide congestion relief.

I passed along to him my thoughts about this program.

Based on what I have read over the past several years, there is a profound paradigm shift going on in transportation planning. The conventional thinking (that I reject quite vigorously) concludes that the way to effectively ease congestion, excessive energy consumption and air pollution problems is to:

  1. Increase road capacity by adding travel lanes and turn lanes and one-way streets;
  2. Enhance “free-flowing” conditions for cars with timed signal lights, wider streets, and other techniques that reduce “friction”;
  3. Provide abundant and free parking at all urban destinations so that people will not have to “hunt” for a place to park; and
  4. Build cleaner, more fuel efficient vehicles.

You will notice that none of these techniques do anything to modify unsustainable American behavior towards more sustainable behavior.

Engineers and politicians in this country have always believed it is “unAmerican” to do things to modify behavior so that it is more socially responsible and sustainable. Instead, the engineer does what he or she is trained to do, and that is to tinker with the technology to solve problems.

When all you have is a hammer, all problems look like nails.

Engineers don’t have any training in human behavior.  No need to manipulate mysterious, irrational human behavior! Only totalitarians would do that, after all. The solution to energy and water problems is to enhance supply…

The newly emerging paradigm in transportation and environmental management is that solving problems by “enhancing supply” is not sustainable. We must do things that modify behavior (demand) so that it is more sustainable.

One very effective way to do that is with pricing, and if the market cannot properly price scare or vulnerable ecological and other resources, we need government to step in.

When it comes to transportation, we need to use both pricing and scarcity to modify demand toward sustainability. What the engineers and elected officials did not know (or were happy to ignore) is that doing things like increasing road capacity (road widenings, turn lanes, etc.) or providing more free and abundant parking (and other forms of transportation subsidies) totally swamps any gains we might realize in terms of reducing “stop and go” traffic, or in terms of getting more “free-flowing” traffic.


Because increasing transportation facility supply makes it easier and cheaper to unsustainably drive a car everywhere, which modifies behavior in an unsustainable direction. We do nothing to discourage “low priority” motor vehicle trips, such as a drive across town to rent a video. With the heavy subsidies to enhance supply, we almost beg people to make such trips and live in remote, sprawlsville locations.

As a result, many recent studies are finding that increasing supply (primarily by widening roads with more travel lanes or turn lanes) eases congestion for only a tiny period of time, after which the congestion becomes worse than before we Carmageddon highwayspent millions to “correct” the problem. The most concise, profound explanation of this is by Anthony Downs, who calls it “The Triple Convergence” in his Stuck in Traffic book. We are inevitably affected by the Triple Convergence when we add capacity to our transportation system, so every time we add capacity by widening roads, we make things worse.

An important corollary here is that transportation drives land use. It is our transportation system that will determine if we have sprawl into our outlying, environmentally sensitive areas — not regulations, land use plans, or enlightened politicians.

Increasingly, therefore, honest and informed researchers and planners are referring to the problem of “induced demand,” in which we always get more vehicle trips after widening roads. Apparently, it is perfectly okay for defenders of the status quo to modify demand when it moves us toward unsustainable consumption…

These informed researchers and planners increasingly call for “planned congestion,” in which we passively apply none of the conventional “supply” methods (expanding road capacity, etc.) to address congestion. Instead, existing congestion is leveraged as a very effective way to get compact development, discourage sprawl, reduce air pollution, and reduce gasoline consumption.

Because congestion discourages motor vehicle trips (and encourages bicycle, bus, carpool and walking trips), research now shows that more congested areas (on an area-wide basis) produce less air pollution and gas consumption.

Because this seems so counter-intuitive and non-sensical, politicians, engineers, and real estate people (who benefit from unsustainable transportation and sprawl) can get away with claiming that road widenings, turn lanes, free and abundant parking, etc. will reduce air pollution and gas consumption.

But it is just not true.

Expanding road and parking capacity ignores the behavior-modifying effects of increasing the transportation facility supply, which totally overwhelms the minor benefits to individual cars of enhancing free-flowing traffic.

When we take into account the system-wide impacts and behavior modification that occur when we do things like widen roads, we find that the emperor is wearing no clothes.

Transportation is truly a zero-sum game. Nearly always, if not always, when we make it easier to drive a motor vehicle, we make it harder to travel another way, which profoundly modifies behavior. We should not be fooled into thinking it is inevitable that we are all doomed to live a life of extreme auto dependence, wherein we are forced to make every trip, no matter how trivial, by car.

So in conclusion, we need to be very, very careful when we hear claims that it is best to solve congestion, energy, and air pollution problems by making it easier and cheaper to drive a car. My opinion is that the millions we spend to do that only make things worse.

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Filed under Politics, Sprawl, Suburbia, Transportation

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