Henry Grabar is a staff writer for Slate’s Moneybox and a former fellow at CityLab. He lives in New York.
A new study suggests that traffic reduction should be targeted at particular communities.
Researchers from UC Berkeley and the Massachusetts Institute of Technology have found that when it comes to traffic, some drivers are making you later than others.
How much later? The central finding of the the paper, published today in Scientific Reports, is that while keeping one percent of all drivers off the road cuts traffic congestion by three percent, eliminating the same number of drivers from particular neighborhoods can reduce travel time for everyone else by a whopping 18 percent.
"This is a preliminary study that demonstrates that not all drivers are contributing uniformly to congestion," Alexandre Bayen, a Berkeley professor and coauthor, said in a statement. “Reaching out to everybody to change their time or mode of commute is thus not necessarily as efficient as reaching out to those in a particular geographic area who contribute most to bottlenecks.”
In the San Francisco area, if the drivers kept off the road came from Dublin, Hayward, San Jose, San Rafael and parts of San Ramon, remaining commuters would find their travel time down 14 percent.
The methodology may be as important as the findings. Rather than costly and labor-intensive travel surveys, researchers used a blend of cell tower and GPS data to chart times and speeds, which, combined with population density statistics and road maps, helped them draw their conclusions.
Lead researcher Marta Gonzalez, a professor of civil and environmental engineering at MIT, believes their work could be easily replicated by cities in the developing world to pinpoint the sources of congestion.
Top image: Flickr user Wonderlane.