By Dom Nozzi
November 29, 2007
We all hate it.
But it is extremely important to know that congestion occurs even when there are only a tiny number of cars on the road. Have a look at the images I’ve attached below. One shows 40 people walking and in bicycles. One shows 40 people in chairs. One shows 40 people on a bus. And the other shows 40 in cars.
As you can see, the 40 in cars looks like gridlock.
When a road carries, say, 15,000 car trips per day, which is very common for a larger street in American communities, there are going to be a great many times when well over 40 cars will want to be on a given road at the same time. As an aside, in the year 2000, there were 217,955 people in the county I lived in while in Florida, and 239,621 motor vehicles registered.
The only possible way for nearly all county residents to travel ANYWHERE was to travel by car. So we had 220,000 residents owning 240,000 cars in the year 2000 in the county. On average, people make about 11 car trips per day. Even if the county I lived in saw an enormous number of motorists decide to drive less due to expensive gas, we would still have had an enormous number of motorists who would have continued to want to drive the local roads. It is hard for me to imagine that the drop could have been so substantial that we’ll rarely or never see 40 cars (or a similarly modest number of cars) on a major road at the same time.
Don’t forget induced demand. This theory, in part, tells us that a number of motorists are dissuaded from driving at rush hour, or on a congested road, or decide not to travel by car, when there is congestion. When we widen a road or, in this case where my county was proposing to synchronize traffic signals, congestion briefly declines. That motivates many of these dissuaded motorists to return to car travel on that road (the motorist has been “induced”). This is precisely why we cannot build (or time our traffic signals) out of congestion.
Anything that (temporarily) frees up traffic bottlenecks quickly gets filled up again by motorists who were previously dissuaded by the congestion.
For these reasons, I am thoroughly convinced that it is nearly impossible for us to escape congestion in a community that has more than a tiny number of motorists (as Anthony Downs has so clearly pointed out in Stuck in Traffic). As an economist would quickly note, any time you have an unpriced good or service that is in high demand, the inevitable result is over-consumption (or in this case, congestion). The only durable way to avoid congestion is to price roads properly with congestion fees. Widening roads, the economist will tell us, quickly results in congestion when those roads are underpriced (or in nearly all cases in America, “free”).
Similarly, we should not build a bigger coal power plant when we have electrical demand that exceeds supply – PARTICULARY if the electricity is unpriced or free (as is the case with roads and most parking). Instead, the only durable way to ensure that supply is adequate for demand is to induce more conservation via proper prices for electricity.
As a result of all this, an important part of my message in my books and speeches is that it is a tactical blunder to posit that better bicycle, transit, or pedestrian facilities will result in a meaningful reduction in congestion. When each of these “progressive” tactics or influences for congestion reduction fail to reduce congestion, as my observations above suggest is nearly certain, the pro sprawl lobby will quickly point out that all this effort to improve transit, bicycling, or pedestrian services or facilities were a complete waste of time and money. The pro sprawl folks are likely to scream, “Let’s get serious and realistic here! Let’s widen roads to reduce congestion!! Your soft-headed tactics have failed!”
The best tactic to address the pro-car, pro-sprawl folks is NOT to claim that bicycling, transit, and pedestrian services and facilities will reduce congestion. I don’t believe even in our wildest dreams will that happen. I firmly believe that instead, the winning tactic is to strongly urge that instead of trying to reduce congestion, we strive to establish ALTERNATIVES to the congestion, so that people who are unwilling to tolerate it can do something else: Use transit, ride a bike, live closer to work, travel at non-rush-hour times, etc. Transportation and lifestyle choice, not congestion reduction is, in my opinion, the best strategy.
The pro-car lobby will always win if we argue for congestion reduction (in other words, we will end up adopting the failed policies of widening, timing signal lights, etc.).
Two things are essential:
- I am thoroughly convinced that we cannot escape or meaningfully reduce congestion (at least in our lifetimes, and for the reasons I point out above).
- In cities, traffic congestion is our friend. Any city worth its salt has a congestion “problem.” Congestion is a sign of success. (As Yogi Berri once said, the place got so crowded that no one went there anymore.) We need to leverage congestion to effectively help us to reduce sprawl, encourage infill and more compact housing, reduce low-value car trips, reduce high-speed driving, promote mixed-use development, reduce noise pollution, reduce the number of severe car crashes, reduce gas consumption and air emissions, improve the health of local retail, promote non-car travel, and improve facilities and services for transit, bicycling and walking.
I know of nothing that more effectively achieves the items in #2 more than congested roads in cities. It is no coincidence that some of cities have been known to openly state they are going to “let it be” when it comes to congestion, and will not use conventional strategies to try to (hopelessly) reduce it.
With regard to the idea of “solving” congestion by synchronizing traffic signals: Even if we assume that, somehow, the community in question can violate the Iron Laws of Physics by being the only community in the known universe to be able to escape Induced Car Travel Demand, and even if we therefore assume that traffic signal timing will forever result in motorists saving 12 seconds in their car trip, does this really justify our spending, in the case of the Florida county I lived in, $20 million in tax revenues? Since when does saving a few commuter seconds become the answer to my county achieving a gloriously high quality of life? Of course, in reality, what we are really doing is spending $20 million for a few years of saving a few seconds. After that brief time, induced demand will result in a return of the congestion we naively thought we could eliminate.
Given this, the decision of my county at that time to spend $20 million for traffic signal timing borders on being criminal, given what we now know.