One of the major components of the Sedona in Motion transportation plan has been scrapped by the Arizona Department of Transportation and the city of Sedona agrees.
In 2018 the city of Sedona entered into an agreement with ADOT to split the costs associated with installing slip lanes at the intersection of State Routes 89A and 179, but that has now changed.
“It was determined that the cost of the improvements is not supported by the benefit,” City Engineer Andy Dickey said.
Had the slip lanes been installed, it would have allowed right-turning drivers to bypass the roundabout. The right turns would have been made more efficient because the slip lanes only require drivers to merge at the end of the lane rather than fully yielding to enter the roundabout, and the slip lanes would have removed those vehicles from the capacity of the roundabout. In addition, the modification was expected to significantly benefit eastbound traffic that backs up on Cooks Hill.
“I and other city staff have been a part of the project team, so we made the decision together,” Dickey said.
In terms of the benefits of slip lanes, Dickey said they would have reduced congestion, measured in level of service and delay, provided by improving the efficiency of the intersection and adding capacity with the slip lane.
In a memo to the city, ADOT’s Mackenzie Kirby wrote, “After a thorough analysis of the data, the ADOT project team and city of Sedona did not see enough of a benefit from the dedicated right-turn lane test, which began in May and ended in early July, and the slip lane modeling, to continue moving forward with the project as previously scoped.
“As a result, the proposal to put a slip lane from State Route 89A from West Sedona to southbound State Route 179 through the ADOT property will not be pursued, no lanes will be added or changed, and there will be no encroachment on private property.”
Despite the state not taking part, Dickey said the city intends to implement minor improvements including signing, striping and minor pavement rehabilitation.
“We also plan to shift focus onto improvements that can be made at other locations in the area, like northbound 89A into and through Uptown,” he said. “We will look at new ways to improve traffic flow in this area, however, a new project will take longer to pursue and therefore end up lower on the priority list.”
