PHOENIX (3 TV / CBS 5) Valley drivers will encounter a new kind of traffic interchange in the next few months. Two new diverging diamond interchanges will be opening along the new South Mountain portion of the Loop 202.
“As a driver, I know it’s going to be a little bit concerning,” said ADOT spokesman Tom Herrmann.
That’s because these interchanges have you driving on the left.
As drivers approach the interchange, they go through a controlled intersection with a light. One direction of traffic moves at a time, shifting traffic over to the left side for vehicles entering the Loop 202, and shifting traffic back over the right side for vehicles exiting the Loop 202.
The interchange makes the shape of a diamond, hence the name.
“Because you’re never turning left across traffic there’s no need for a left turn arrow. So traffic moves a little more smoothly with a diverging diamond,” Herrmann said.
The two diverging diamond interchanges will go in at Desert Foothills Parkway and 17th Avenue. They’ll be a first for the state.
Technically, both will be half diverging diamond interchanges because local traffic is unable to go south onto the Gila River Indian Reservation.
There are two others planned elsewhere in Arizona.
One will go in at I-17 and Happy Valley road sometime next year, and another is planned in the Tucson area in the next few years.
And if these interchanges perform well, ADOT could be installing more.
“There’s no reason to believe these won’t go well,” Herrmann said.
[SPECIAL SECTION: Phoenix Traffic]