Metro and Caltrans' $444+ million dollar SR 57/60 Confluence Chokepoint Relief Project has been taking shape steadily since breaking ground in mid-2023.
The project is meant to reduce congestion and collisions along the two mile freeway stretch where the 57 and the 60 share the same trunk, in Diamond Bar and City of Industry. This reconfiguration has been in the works since 2011 and is anticipated to finish in 2028.
Metro/Caltrans 57/60 project construction is administered by the San Gabriel Valley Council of Governments (SGVCOG). The COG's project webpage terms the 57/60 confluence as the seventh worst trucking bottleneck in the country. An estimated 100 million vehicles pass through the confluence each year.
This stretch of roadway serves major job centers: City of Industry, Orange County, the Inland Empire. Bearing north toward the San Gabriel Mountains, warehouses continue along the 57.
As State Senator Bob Archuleta attests, when one drives into the confluence at the wrong time, "it takes about forty minutes to go two miles."
The reason for this long uncomfortable handshake of two freeways is the underlying terrain. The confluence is a narrow valley (and a waterway) slung between the San Jose Hills and Chino Hills.
Add into the mix an off-ramp for Grand Avenue right in the middle, where the weave zone to change freeways is, and things can get pretty hairy. The confluence sees an average 186 crashes yearly, according to this injury law firm.
The westbound (technically southwestbound) side was already retooled (adding a freeway lane, and new and wider ramps) about a decade ago. So now it’s the dreaded Eastbound 60/Northbound 57 side that’s getting worked on currently (phase III). Current improvements are largely being made completely off the trunk of the freeway.
Components in-progress
Eastbound Grand Avenue Bypass Off-Ramp
The southwest part of the project adds a new mile-long two-lane off-ramp, which allows eastbound 60 drivers to easily exit at Grand. The off-ramp will “fly over” the northbound 57.
Here, 60-foot foundation piles have been placed, as well as an abutment (#6). Retaining wall reconstruction is ongoing. See top photo for another perspective.
Grand Avenue Bridge/Interchange
The overpass bridge will be reconstructed for eight lanes with a new loop onramp for southbound Grand Avenue to the eastbound 60. The very beginning of the onramp’s concrete is taking shape here, alongside the golf course nets. Utility relocations are ongoing. A large retaining wall structure has been finished in the middle of the loop.
SR-60 Eastbound Bypass Connector
The other new large flyover structure will be a half-mile long elevated bypass for northbound drivers (on the 57 or entering at Grand) to access the eastbound 60 without having to weave left around the 57 north ramp. This area is completely excavated and shored, while utilities are still being relocated. Concrete flyover structures will begin rising next year.
Diamond Bar Boulevard Eastbound Onramp
The eastbound 60 Diamond Bar Blvd. onramp is being realigned to accommodate the eastbound 60 flyover connector. The ramp will be widened from two to three lanes. Excavation and utility relocation are ongoing here.
Otherwise, retaining and sound walls are under construction throughout the project area.
Ongoing closures and traffic pattern changes are scheduled along Golden Springs Drive in Diamond Bar as well as restriping on Grand Ave.
The SGVCOG's anticipates Grand Avenue Bridge demolition next year. The two flyover ramps are expected to be completed in 2027.
The current phase of the project is funded with $240 million from state Trade Corridors Enhancement Program and $205 million from Metro’s Measure M sales tax.
Altogether, the project is adding a little over eight miles of driving lanes, about 600 feet of bike lanes, and widened sidewalks (from five to eight feet) on the Grand Avenue Bridge .
This freeway expansion does not demolish any homes or businesses, but did impact the public golf course (shrinking it by five percent) and took small slivers of land from a few adjacent business sites.
The project will increase capacity for driving, including goods movement via truck traffic. It provides construction jobs. Drivers entering/exiting at Grand will likely feel the most benefit, while those taking the 60 east to the 57 north will still have to weave.
As with all freeway expansion, the increased highway capacity will induce more driving, bringing more congestion and emissions.
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