Newswise — A first-of-its-kind tool that highway planners can use to accurately forecast freight and truck traffic was unveiled this week by researchers from The University of Alabama in Huntsville.
Developed in UAHuntsville's Office of Freight, Logistics and Transportation (OFLT), the tool could augment passenger car-based traffic forecasting models that have under estimated both the volume and the growth of truck traffic by more than 100 percent.
"We're trying to figure out how to plan for freight transportation needs," said Greg Harris, the OFLT director. "We are studying infrastructure and freight, and how they work together to support economic growth."
The UAHuntsville forecasting team's first regional client is the Mobile Metropolitan Planning Organization. Harris and his team presented a summary of the project and a projection of Mobile-area freight growth through 2035.
"This is the first MPO that we are aware of to take the initiative to try to integrate comprehensive freight planning into its transportation plan," Harris said. "The best thing our work has done is raise the level of understanding of what the issues are. For instance, there are traffic flow issues in Mobile at the I-10 tunnel, but the analysis revealed more depth of constraint on freight traffic than had been previously known."
More accurate estimates of truck traffic volume -- frequently between eight and 25 percent of all vehicles on major highways -- might change everything from plans for future roads to highway maintenance schedules.
"Because of the lead time involved in these projects," said Harris, "you can't count vehicles today and say, 'I have a problem and I need to start building.'"
To create the forecasting model, the UAHuntsville team divided the state into 27 freight zones, and then studied population, businesses and specific industries in each zone to get a clear picture of how many trucks are moving in and out of each zone. The model also gives planners a better idea of zones where traffic might grow the fastest.
"Now that we know what industries are in Alabama and their locations, we can do a growth projection by industry type over the next several years," said Harris. "For instance, in 1990 how much freight would anyone have forecast for Alabama in the auto industry? With the right growth data we can query the models and ask where are the congestion issues we need to deal with to promote economic development?"
A combination of regional, statewide and local data gives the UAHuntsville team's forecasts unique flexibility.
"We have the ability to focus on how our actions might change volume on one specific stretch of road," said Dr. Michael Anderson, an associate professor of civil engineering and a member of the OFLT team. "We can calculate the number of vehicle miles traveled if one stretch of highway is built or improved versus spending that money on a different stretch of highway.
"That can help set project priorities. We can begin to answer the question, 'Which of these options is best?' That is especially important if the state has 15 priority projects on the books but only has funding for three."
Anderson also developed a technique for estimating the volume of "pass through" truck traffic that neither starts nor stops in Alabama.
"One of the surprising things we found was the volume of pass through traffic," he said. "Now we can add that to our forecasts as a base flow of traffic that is just passing through. We are finding the traffic flows that are going to have an impact on Alabama, but have no control over. Until now, there was no way to assess pass through traffic volume."
The team's data is already in use at the state level: The freight component of the Alabama Department of Transportation's five-year plan is UAHuntsville's projection
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