Study: Truck-only lanes won't relieve Atlanta traffic

A Georgia Department of Transportation study has thrown water on a proposal to ease traffic congestion on metro Atlanta's interstate highways by restricting some lanes to trucks.

But David Doss of Rome, Ga., the State Transportation Board member who has been the chief advocate of truck-only lanes, said he's not ready to give up on the idea.

"I'm not convinced truck-only is a dead issue," Doss said Wednesday during a meeting of the board's Public/Private Initiatives Committee, which he chairs.

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The study examined how designating truck-only lanes throughout the metro region's interstate network or on portions of the system would affect the volume and flow of traffic, particularly during peak hours.

The answer? Not enough to justify the $13.2 billion cost of setting aside truck-only lanes throughout the system.

Matthew Fowler, the DOT engineer who presented the study, introduced board members to the concept of "latent demand."

He said that steering trucks into designated lanes would create additional traffic capacity in an interstate highway's general-purpose lanes. However, he said that extra space soon would be eaten up by "new travelers" drawn to free-flowing highways from the parallel surface streets that drivers now use to get around congested interstates.

As a result, designating truck-only lanes throughout the system by 2035 would reduce traffic volume by only 4 percent, from 166,000 vehicles per day to 160,000, according to the study.

Fowler said targeting truck traffic would be ineffective especially during the morning and evening peak periods because truckers already avoid Atlanta-area highways during those hours.

He said heavy trucks account for only 6 percent of the region's interstate traffic during peak periods.

"At the time we need the most capacity -- we're focusing on the smallest slice of the market," he told committee members.

Fowler said the numbers were even more discouraging when the study examined the possibility of charging truckers a toll to use the designated lanes.

He said tolls would only generate an estimated $3.3 billion over 30 years, leaving the project with a huge funding gap. At the same time, tolls would discourage truckers from using the truck-only lanes, resulting in even less congestion relief on general-purpose lanes.

But Doss said truck-only lanes still are worth considering. He said the DOT study failed to take into account improved safety that would result from separating cars and trucks on interstate highways.

He also argued that something will have to be done to accommodate a huge increase in truck traffic in the Atlanta region anticipated during the next seven years due to expansion of the Port of Savannah.

"It may cost $13 billion to build this system," Doss said. "(But) there is a real economic value to having competitive and reliable freight movement in this state."