Two Chicago-area interstate highways had the worst truck traffic congestion of any interstate exchange in the United States during 2009, according to a study released last week by the Federal Highway Administration (FHWA) and the American Transportation Research Institute (ATRI).
The study was designed to determine how severely traffic congestion affected motor freight movements during the year. The findings, based on GPS technology and methodology developed by ATRI, assigned what FHWA called a congestion index to 100 busy locations monitored on weekday periods.
The study found the heaviest truck traffic congestion in the country was at Interstates 290, 90, and 94 in Chicago. That was followed by the nearby interstate confluence of I-90 and I-94 north of Chicago heading for neighboring Wisconsin. Rounding out the top five were Interstate 95 and state road 4 in Fort Lee, N.J., adjacent to the George Washington Bridge linking New York and New Jersey; Interstate 35 in Austin, Texas; and Interstates 285 and 85 outside of Atlanta, an area known as Spaghetti Junction because of the twisting maze of roads and ramps that bedevil truckers and motorists alike.
The congestion index is based on a measure of average speeds at a given location that fall below what the study calls free flow speeds of 55 miles per hour. For example, the average truck speed at the Chicago-area intersection considered the most congested was only 30 mph. The average truck speed at that intersection during peak driving periods was 23 mph, with truck speeds of 33 mph during non-peak driving times.
FHWA said it hopes the findings will aid public and private sector interests in developing programs to increase mobility both in the bottlenecked areas and throughout the country's freight corridors. The survey will continue on an annual basis, FHWA said.