Acknowledging that highway investments drive up car use and traffic, transportation professionals and advocates have grown more interested in accounting for induced demand in transportation investments. But the laws of induced demand are not limited to highways. As several cities have shown, investing in bicycle infrastructure can increase bike use by 100% or more.
induced demand
USDOT could advance travel modeling and help planners account for induced demand
A provision of the Bipartisan Infrastructure Law (Sec. 11205) requires USDOT to review existing travel demand models and, among other things, consider the potential implications of induced travel. Federal officials, committed to that mandate, were at the TRB annual meeting last week to learn from modeling experts and practitioners. This blog post offers one perspective on the issues and lays out several opportunities gleaned through discussions at TRB.
Adding road capacity is fruitless, another study finds
As cities grow and traffic increases, road capacity investments offer diminishing returns and even make traffic worse, according to a recent international study. Looking at 24 cities across the globe, researchers found that for every one-percent increase in road capacity, average traffic speeds drop 0.014 percent. Public transportation doesn’t suffer the same consequences.
Transportation agencies are facing the consequences of induced demand
Induced demand. It’s a concept that used to be popular only among the wonkiest transportation experts, and now gets covered by outlets ranging from the Washington Post to the Wall Street Journal. Governing calls it “the almost universally accepted concept” that almost no one understands, while Strong Towns calls ignorance of the concept “professional malpractice.” With new tools and a better understanding emerging, some transportation agencies are now beginning to wrestle with the implications.