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ATRI study addresses impact of congestion on fuel consumption

Atlanta’s ‘Spaghetti Junction’ used to illustrate effect of traffic on usage

Posted March 12, 2019

An American Transportation Research Institute (ATRI) case study of the “Spaghetti Junction” interchange in Atlanta, Georgia, illustrates the effect congestion has on fuel consumption in the trucking industry.

In its analysis, ATRI estimated the fuel consumption and emissions impact of congestion at the interchange of I-285 and I-85 in Atlanta, considered one of the worst bottleneck traffic locations in the country.

The study found that increasing average vehicle speeds to 55 mph during the weekday evening commute would save 4.5 million gallons of fuel annually. Current averages are as low as 14 mph during the same time frame. Emissions reductions were estimated to be 17 percent for fine particulate matter, 5.5 percent for smog-forming NOx emissions and 8 percent for carbon dioxide emissions.

ATRI studied vehicle speeds by time of day, daily trip counts collected by the Georgia Department of Transportation, and emissions factors derived from the U.S. Environmental Protection Agency’s state-of-the-science emissions model and data from ATRI’s truck GPS database.

Nationally, congestion is estimated to have raised the industry’s fuel consumption by 6.87 billion gallons in 2016, equating to an additional $15.74 billion in costs.

The study is the second in ATRI’s “Fixing the 12%” research initiative. The organization previously found that 89 percent of the trucking industry’s costs are generated from just 12 percent of interstate highway miles.

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