Shutterstock

Researchers in Denmark found that municipalities underestimate the economic and environmental impact of new roads.

Here's an all-too-common phenomenon - a city decides to build or expand a road to decrease traffic. The road is built. Traffic increases instead. This is called induced demand, whereby drivers avoiding the road because of congestion jump back onto it once the project is finished.

But municipalities often fail to properly account for this phenomenon, according to a new study of out Denmark.

The researchers found that "the traffic-generating effects of road capacity expansion are still often neglected in transport modelling." This can lead cities to make mistakes when assessing the environmental impact and economic vitality of proposed road projects.

As Streetsblog writes:

According to the study, completed by researchers at the Institute of Transport Economics and a Danish university, this leads to skewed cost-benefit analyses that call for new highways and road widenings of dubious benefit to the public.

Researchers reported that perceived time savings make up the largest portion — sometimes 85 percent — of the economic benefits assigned to prospective highway projects. But an unanticipated boost in traffic volume can turn many projects that would theoretically pass analytical muster into economic losers. Unless transportation agencies are carefully accounting for these effects, however, many of these projects get built anyway.

Photo credit: chaoss /Shutterstock

About the Author

Most Popular

  1. Times Square, 1970.
    Life

    The New York That Belonged to the City

    Hyper-gentrification turned renegade Manhattan into plasticine playground. Can the city find its soul again?

  2. "Gift Horse"—a skeletal sculpture of a horse by artist Hans Haacke—debuted on the Fourth Plinth in London's Trafalgar Square in 2015.
    Design

    What To Do With Baltimore's Empty Confederate Statue Plinths?

    Put them to work, Trafalgar Square style.

  3. President Donald Trump speaking at his press conference at Trump Tower.
    Infrastructure

    Trump's Infrastructure Plan Only Has One 'Side'

    Trump’s obsession with building big things fast doesn’t seem unrelated to his defense of white supremacists.

  4. New public notice signs from Atlanta's Department of City Planning.
    Design

    Atlanta's Planning Department Makeover

    A new seal, a new name, and most importantly, new signs that people will actually read.

  5. Maps

    This Guy's Never Met a Map He Didn't Want to Fix

    Just not always for the better: "I've deliberately designed maps that are deliberately horrible to look at, and succeeded."