Work is underway to create California’s first diverging diamond interchange. It’s a traffic design engineers say will reduce collisions and improve traffic flow along Highway 120 and Union Road in Manteca.
“It forces traffic to drive on the opposite of the road and that’s the point,” said Matt Brogan, Principal, Vice President at Mark Thomas in Sacramento.
At many traditional freeway interchanges, drivers must wait at a stoplight in order to turn left in front of oncoming traffic.
At a diverging diamond interchange, drivers use stoplights to transition from the right side of the road to cross over to the left side at the interchange and then back again after passing through the interchange.
“So in order to get onto the freeway you’re making a free left turn and to get off the freeway it’s a free left turn. So what you see is that the broadside left turn movements are eliminated,” Brogan said.
The number of conflict points are reduced from 26 at a traditional left-turn interchange to 14 at a DDI, Brogan said.
The project, which includes a separate path for pedestrians and bicyclists, is expected to be completed in 2020.
While new to California, DDIs are already in use in other states like Nevada, Utah and Missouri.
Source: July 10, 2019, Mike TeSelle, KCRA
“California’s first diverging diamond interchange coming to Manteca”
Link: https://www.sfchronicle.com/bayarea/article/Prepare-to-be-perplexed-New-diverging-14106699.php
