A new kind of freeway interchange is coming to California — possibly to Berkeley, in time — and it’s likely to make drivers scratch their heads in confusion.
It’s called a diverging diamond. To enter the freeway, the cutting-edge interchange requires drivers to veer at a 45-degree angle across the center divide, switching sides with opposing traffic and briefly motoring across as if they are in England.
By being on the left side, they can then glide left onto the highway without a dangerous 90-degree turn across oncoming cars.
Transportation officials broke ground on the state’s first diverging diamond interchange late last month where Union Road crosses Highway 120 in Manteca (San Joaquin County). The interchange is not scheduled to open until fall 2020, but the design’s popularity is spreading.
At least two more diverging diamonds are planned in the Central Valley, and engineers are considering the design for the reconstruction of the Ashby Avenue interchange over busy Interstate 80 in Berkeley.
Some traffic planners are smitten with the concept and how, in the name of efficiency and safety, it forces opposing traffic to negotiate an X-shaped, signalized crossover before a bridge or underpass. As freeway-bound drivers drift to the left to an on-ramp, those heading through the interchange to the other side of the freeway follow the road back to the right at another crossover.
Source: July 19, 2019, Michael Cabanatuan, San Francisco Chronicle
“Prepare to be perplexed: New diverging diamond interchanges coming to California”
https://www.sfchronicle.com/bayarea/article/Prepare-to-be-perplexed-New-diverging-14106699.php
