Chicago Area Has Worst Traffic Bottleneck, Study Finds
This story appears in the March 23 print edition of Transport Topics.
The worst U.S. traffic bottleneck is on the south edge of Chicago, according to a pioneering study that uses electronic data from trucks — a research method that could influence future transportation spending debates.
The American Transportation Research Institute study, released earlier this month, prioritized 30 of the nation’s well-known bottlenecks by analyzing the speed and time of day trucks traveled through them.
“As far as we know, we’re the only organization out there doing this with real-world truck data,” said Daniel Murray, vice president of research for ATRI.
The data collected from wireless onboard communications systems have made it possible to find average bottleneck speeds over 24-hour periods.
At the worst bottleneck, for example — where interstates 80 and 94 meet — the median truck speed in late afternoon is a little more than 35 mph, the study found.
Chicago is also home to the third-worst bottleneck — where Interstate 94 meets Interstate 90.
The study also found that at the second-worst bottleneck, median speed fell below 10 mph at 8 a.m. That choke point is in Fort Lee, N.J., where Interstate 95 meets State Route 4, just west of the George Washington Bridge into Manhattan.
In previous studies, California dominated the list of worst bottlenecks with as many as four in the top 10. In one of those federal studies, for example, Los Angeles had the nation’s top bottleneck — where Interstate 710 meets Interstate 105.
Using ATRI’s research method, however, the Los Angeles interchange fell to 14th, and the entire state of California had only two of the top 10 bottlenecks.
The onboard data make it possible to prioritize bottlenecks more accurately, which could be important for policy-makers trying make effective allocations of limited transportation dollars, Murray said.
Jeffrey Short, the senior ATRI research associate who oversaw the study, said, “We are not trying to direct these funds. We’re trying to give the public a tool by which to assess how bad certain infrastructure is.”
The study, however, is important to groups such as American Trucking Associations because it is a step toward a scientific system that could clarify debates on highway reauthorization, said Ted Scott, director of special projects for ATA’s department of federation relations and strategic planning.
“We want our money spent in ways that improve our freight flow at [these] bottlenecks,” Scott said.
ATA has called on Congress to raise the federal fuel tax as part of the reauthorization and to dedicate that revenue to improving freight mobility nationally.
The ATRI bottleneck study is linked to a federal effort that began in 2002 to improve freight mobility; ATRI said the starting point for its study was a list of 30 bottlenecks supplied by the Federal Highway Administration.
That list, however, never had been prioritized using onboard truck data. The federal government has been collecting such data under strict privacy agreements with telecommunication and trucking firms, according to the FHWA’s freight mobility project Web site.
In the past, bottlenecks have been ranked using data supplied largely by the states and collected by electronic highway counters. Onboard data, however, allow ATRI to better “calibrate and evaluate” existing bottleneck research, Murray said.
