As we have previously stated the DOT has planned an unprecedented number of highway widening projects within the Town of Brookhaven. Widening roadways is almost always an attempt to reduce traffic congestion. Unfortunately, as Andres Duany, Elizabeth Plater-Zyberk, and Jeff Speck state in their book, Suburban Nation, widening roadways does nothing to reduce traffic, and in fact in the long run will make it worse. This, of course is a difficult concept to swallow. Common sense would dictate that additional lanes would reduce traffic congestion. However, the phenomenon, known as generated traffic, has been well documented.
Duany et.al state that this paradox was noticed by Robert Moses as early as 1942, when he discovered that the roadways he had built around NYC in 1939 were creating greater traffic problems than had formerly existed.
In an area known for its sprawling development patters, the Southern California Association of Governments conducted a study which concluded that traffic mitigation measures such as adding lanes, or even double-decking the roadways, would have only a “cosmetic effect” on Los Angeles traffic problems. A second study coming out of the University of California at Berkeley which studied 30 California counties between 1973 and 1990 found that: “for every 10 % increase in roadway capacity, traffic increased by 9 % within four years time.
Studies conducted by the British government also show that increased capacity results in increased automobile usage. The British have concluded that half of any driving time saved by new or wider roads is lost in the short run, and that in the long run all savings are expected to be lost.
As Duany et al conclude: “The question is not how many lanes must be built to ease congestion, but how many lanes of congestion you want.”
This phenomenon of generated traffic can also be explained through a concept called latent demand. The factor which limits our driving trips is traffic. When traffic disappears, people are ready to drive more. Latent demand makes adding lanes pointless, since drivers are poised to fill them.
As Duany et al state: “...from Maine to Hawaii, city, county, and even state engineering departments continue to build more roadways in anticipation of increased traffic, and in so doing, create that traffic. The most irksome aspect of this situation is that these road-builders are never proved wrong: in fact they are always proved right: “you see”, they say, “I told you that traffic was coming.”
The highway widening projects which have been proposed for the Town of Brookhaven will have an enormous impact on the future of our communities. It is, therefore, time to convince our Federal, State, and County representatives to stop pouring billions of dollars into road widening projects which do nothing to resolve the problem which they target. If our traffic engineers insist on ignoring this difficult lesson we must begin to teach it to our elected representatives who vote to fund such projects. Congestion cannot be widened away. Indeed the billions of dollars which we have spent over the last twenty years has only increased the amount of time in which we spend behind the wheel. We now drive twice as many miles per day as we did 20 years ago.
Certainly, even the DOT can understand that in developing areas we can only temporarily have congestion free roads. In such areas more transportation capacity equals more development, and increased congestion. Not allowing a natural congestion price to occur simply generates congestion. Such is the case along many of the highways slated to be widened throughout Brookhaven. A particularly good example of such a increased capacity/increased development/increased capacity cycle is Rt. 347. Unfortunately, the DOT is again proposing to resolve current congestion problems by increasing capacity. One does not have to be a genus to figure out what will happen next.
Norman Bel Geddes, the designer of the U.S. Interstate system, declared in 1939, “Motorways must not be allowed to infringe upon the city.” The flip side of this rule is that the city can not grow along high speed highways. Where high-speed roads pass through the countryside, roadside development should not be permitted. The results of these rules are plain to see in much of western Europe: cities, have kept their pedestrian-friendly quality, and most highways provide views of uninterrupted countryside.
Where they do provide access to communities, highways should take on the low-speed geometries of avenues and boulevards. We must design our roadways which travel through our communities so that drivers are encouraged to drive at no more than 30 mph, and we must provide for the comfort, access, and safety of cyclists, and pedestrians.
We will not solve our transportation problems by investing in ever wider roadways. We will resolve them through intelligent design, and by enhancing the viability of a diversity of transportation options.
Who's Who? For information about this author and our consultant team click Here
Citations:
Duany, Andres, Plater-Zyberk, Elizabeth, & Speck, Jeff. Suburban Nation, 2000, North Point Press
