"Recent publications argue that expanding urban highways is a cost effective and desirable way to reduce traffic congestion (TDA, 2003; AHUA, 2004; Cox and Pisarski, 2004; Hartgen and Fields, 2006). They claim that highway expansion provides congestion relief, a seductive term since traffic congestion is stressful and imposes economic costs. People understandably want relief. But this may be an example of a misguided solution that exacerbates the problem it was intended to solve and has undesirable unintended consequences.
As an analogy, consider the role laxatives should play relieving constipation. Laxatives are sometimes appropriate, but it is generally best to address constipation by changing diet (more fiber and liquids) and exercise (take a walk), because laxativesâ€™ effectiveness declines with frequent use, they can hide more severe diseases, and they can exacerbate other medical problems. A physician who prescribes laxatives without investigating why the patient is constipated or considering other solutions is guilty of malpractice.
Similarly, chronic traffic congestion is often a symptom of more fundamental community design problems, such as inadequate mobility options that force people to drive for every trip, and dispersed land use patterns that increase travel distances. Where this is true, expanding roads may reduce short term symptoms but exacerbate long term problems. "