induced traffic

Conventional practice fails to account for induced traffic, even when the public demands it

By Eric Sundquist The problem of induced traffic, aka induced demand, is well-documented in the literature. Yet it is too rarely accounted for in practice. A new paper by Jamey M.B. Volker (University of California-Davis) and co-authors examines the environmental documents from five major highway

Dueling congestion reports released

By Eric Sundquist Two reports issued within days provide contrasting takes on the enduring issue of highway traffic congestion. One report from traffic-data firm Inrix is an update of previous scorecards that rank world cities for highway delay, calculated by aggregating travel times slower than

More highways, more congestion

By Eric Sundquist In pursuit of congestion relief, the United States added 63 percent more urban freeway lane-miles between 1990 and 2017. That rate far outstripped the 46 percent growth in urban population. It didn’t work. As widely reported last month, the Texas Transportation Institute’s

Yet more evidence: “If you build it they will drive”

By Eric Sundquist There’s new evidence, from academia and a prominent real-world case, that ever-expanding highway capacity is a futile strategy for reducing congestion. First, the specific example: Eight years ago Southern Californians famously endured “Carmageddon,” a temporary closure on

A tool to estimate the added VMT from highway expansions

By Michael Brenneis and Eric Sundquist Since passage of S.B. 743 in 2013, California agencies have wrestled with questions around the added travel and emissions resulting from land use and transportation projects. On the land use side, see SSTI’s recent webinars about land-use review reforms in

Bridging the gap between research and practice: new study on the role of induced vehicle travel

By Mary Ebeling A newly released study sponsored by CalTrans offers a thorough review and analysis of research and practice related to the limitations of existing travel forecasting models. The authors focus on limitations in forecasting induced vehicle travel generated by adding lane miles

Highway capacity won’t relieve congestion or lower emissions, studies conclude

By Eric Sunquist A commonly cited strategy to achieve lower emissions and energy use is highway capacity expansion intended to reduce delay. Such a strategy, which has justified many a CMAQ project, is straightforward and appealing to motorists who dislike traffic. But, as a new brief from

Neither roads nor public transit will help?

In the October 2011 issue of the American Economic Review, authors Gilles Duranton and Matthew A. Turner review traffic data from the years 1983 to 2003. Their article, “The Fundamental Law of Road Congestion: Evidence from US Cities,” finds that, for the time period reviewed, congestion