Study Skeptical About Solving Transportation Woes Through High-Density Development
High-density, mixed-use development may not be a panacea for the nation’s snarled highways, according to transportation expert Genevieve Giuliano, who is a professor in the University of Southern California’s School of Policy, Planning and Development.

In the current issue of Urban Studies, Giuliano cites research based on the travel diary data of more than 100,000 individuals from the U.S. and Great Britain leading to the conclusion that there may be no causative link between the centralized metropolitan areas of Europe and its population’s lower use of automobiles.

“The leading idea is that high-density living makes you more likely to walk or to use public transportation,” she said. “But we just don’t have a lot of evidence for it.”

The most striking finding of the study, which was co-written by Dhiraj Narayan, a recent graduate of USC’s Master of Planning and Master of Real Estate programs, is that “how people travel in Britain has very little to do with low-, mid- or high-density living.”

The British take significantly fewer non-vacation trips and travel less per trip than Americans, whether they live in London or a remote village, she said. In the U.S., a person takes an average of 3.8 trips a day covering 28.7 miles, compared to 2.9 trips totaling 14 miles in Great Britain.

The major difference, Giuliano finds, is greater affluence in the U.S., with a median household income of $33,900 in 1999, compared to $21,800 in the UK.

The greater wealth is reflected in car ownership rates: almost one-quarter of British households don’t have cars, compared to 3% in the U.S. And only 3% of the British live in households that have more cars than drivers, compared to 16% in the U.S.

It is also significantly more expensive to operate cars in Great Britain.

A higher quality of public transit and greater mixed-use development also play a role.

“There’s more mixed use everywhere — even in low-density villages,” Giuliano said. “When people have to economize on travel, they have lots more opportunities. High transportation costs motivate people to live closer to work and to use nearby shops and services. In this country, there is no such incentive.”

“The whole idea that Americans will behave differently if only given the chance can’t be supported,” she said. “People do seem to like their cars and, on average, prefer single-family homes.”

As long as transportation is a bargain, people will use it to live, work and shop where they want, she said.

“Trying to build high-density, mixed-use can give you many other good things,” she said, “but it will not materially change the transportation problem.” [ return to top ]