Diamond Bar Freeway Interchange Project Gets $30 Million Grant

DIAMOND BAR, CA — A project to overhaul the interchange linking state Routes 57 and 60 in Diamond Bar took a major step forward Monday after it received a $30 million grant from the U.S. Department of Transportation.

The project has been fully funded since November, but Diamond Bar officials said the grant will kick-start the latest phase of construction, which is set to begin by August 2022 — two years ahead of schedule.

“Improvements in this phase will be concentrated along the 2.5-miles-long segment where the two highways merge creating major bottleneck conditions that contribute to severe congestion and forced lane changes that often result in fatal collisions,” officials said.

Improvements in this project include the following.

• Construction of a new eastbound travel lane.
• Construction of a new eastbound 60 off-ramp bypass lane to Grand Avenue meant to eliminate weaving in and out of traffic for exiting the 60 to Grand Avenue.
• Reconstruction of the Grand Avenue eastbound on- and off-ramps, including an exclusive on-ramp bridge for Grand Avenue traffic to Route 60 that cuts down on weaving movements in the eastbound direction east of Grand Avenue.
• Widening of Grand Avenue and reconstruction of a new wider bridge over Route 60.
• Construction of an eastbound Route 60 on-ramp bypass from the northbound Route 57 split.
• Reconstruction of the eastbound Route 60 Diamond Bar Boulevard on-ramp.

The interchange is considered the sixth most-congested freeway segment in the country and the third worst in the state, according to the Los Angeles County Metropolitan Transportation Authority. Around 100 million drivers travel through the interchange each year.

The segment is also considered the second-highest location for truck accidents in the Southland because of lane mergers and motorists who weave dangerously in and out of traffic, according to the California Highway Patrol. Truck-related accidents occur at a 50 percent higher rate in the interchange than the state average.

U.S. Reps. Grace Napolitano (D-El Monte) and Judy Chu (D-Monterey Park) lauded the funding, saying the project will also have the added benefit of helping the environment.

“Fixing the congestion at this confluence will not only improve safety, it will help ease Southern Californians’ commutes, helping to reduce the amount of pollution in the air from idling cars,” Chu said in a statement.

—City News Service contributed to this report