A $40 million, two-year project to rebuild the traffic interchange at Interstate 19 and Ajo Way (State Route 86) is nearing completion in southwest Tucson, Arizona, and it features a new configuration designed for efficiency and safety.
A second project for the busy interchange will be let out for contractors’ bids in Spring 2018.
The new interchange will feature a widened Ajo Way bridge over I-19 and a single set of traffic signals controlling traffic entering and exiting the interstate, rather than signals at multiple locations.
“We have an opportunity at Ajo Way and I-19 to use a design that allows traffic to move more efficiently through the intersection more quickly because drivers only have to move through one set of lights instead of two,” says James Gomes, regional traffic engineer for ADOT’s South Central District.
Created in 1974 in Clearwater, Florida, the design is called a single-point urban interchange. With this configuration, left-turn drivers from opposite directions can move through the intersection at the same time.
The design accommodates larger vehicles, including trucks and recreational vehicles, better than traditional diamond interchanges can, ADOT says. And while the rate of collisions is about the same with this as with diamond interchanges, the single-point urban interchange has a lower rate of injuries and fatalities, the department says.
