Six lanes or eight

In response to a request from the Asheville City Council last month, the state Department of Transportation has agreed to conduct one more traffic study — beginning immediately — to estimate future traffic volume along the I-26 Connector.

“We are in the process of working on that,” confirmed DOT Traffic Engineer Kevin Lacy. Calibration of the study has begun, Lacy told Xpress, and the test should be completed by early March. The new study once again reopens a 10-year-old controversy over whether the highway should be six lanes or eight.

In mid-November, Asheville Traffic Engineer Anthony Butzek suggested to Council that the city conduct its own test using CORSIM software — a computer-simulation program that he said provides more accurate numbers than the two tests already performed by the DOT.

Those tests returned widely varying results. A 2002 study predicted 143,000 vehicles per day along that stretch of road by 2025, while a later study projected 99,100 vehicles per day by 2030. The first set of numbers is well within the DOT’s range for an eight-lane project; the results of the second test fall right on the border between six lanes and eight.

The long-running issue has stirred up concern among residents of neighborhoods bordering the project, who fear the impact of an eight-lane highway.

Butzek himself asked the DOT to conduct the CORSIM analysis back in July, but he was rebuffed, in part because the local Metropolitan Planning Organization had previously passed a resolution supporting eight lanes. And when Butzek suggested that the city perform the test itself, Council decided instead to send a request to the DOT — noting that Asheville would do its own test if the agency refused.

Although Butzek initially recommended using a basic form of the analysis — which would be cheaper and take less time — the DOT has opted for a more advanced version requiring 120 staff hours over nearly four months. Lacy said the more extensive test was being used in order to assuage any doubt about its accuracy.

The DOT’s prior traffic analyses were based on the Highway Capacity Manual, which Lacy maintained is the industry standard nationwide. But a substantial discrepancy between those projections and the results of the CORSIM test would indicate the need for more analysis, he said.

“If it’s clearly way into the area of not needing eight lanes, then we will sit down and ask where are the differences in the models,” said Lacy. But he also noted that the CORSIM is considered a much more optimistic and forgiving model. (For example, he told Xpress, a CORSIM analysis of the Interstate 40/240 interchange indicated that traffic would never back up at the intersection.)

In addition, Lacy emphasized the complicated nature of any such test, saying that while CORSIM is a good tool, “It is not a litmus test. There is no black or white answer.”

Butzek, meanwhile, told Xpress, “I hope to have the opportunity to review the model once it is completed.” That request was included in the city’s letter to the DOT, he said.