By DONNA BETH WEILENMAN
MARTINEZ, Calif. – After months of construction that led to the closure in April of the southbound exit ramp from Interstate-680 to Marina Vista and Waterfront Road, the new off ramp should be finished some time next month, Allyn Amsk, Caltrans District 4 public information officer said.
“As we get closer, we’ll have a better idea about the date,” he said. However, the district tentatively expects the new ramp to open about mid-October, Amsk said.
Construction on the $15 million I-680 Mococo Overhead Bridge Rehabilitation, as the project is called, began in the summer of 2014 after extensive planning and a presentation to the Martinez City Council in 2013, Amsk said.
During the planning stages, Caltrans learned that removing the old ramp and replacing it with a new one rather than retrofitting the old ramp would cost about the same. The agency also decided to combine this project with the Mococo Road retrofitting.
Amsk said the project is unrelated to a fatal accident that occurred there in 1976.
During the morning of May 21, 1976, a Yuba City High School a cappella choir, 52 passengers total, was traveling to Orinda to spend a friendship day with the choir of Miramonte High School.
The driver of the Yuba City choir’s bus misinterpreted a light that warned him the air brake pressure was low. When the brakes failed, the bus struck the bridge rail and fell more than 20 feet, landing upside down.
The bus’s roof was pushed to the bottom of the vehicle’s windows, killing 28 students and an adult accompanying the choir. Those who survived, including the driver, were injured, some seriously to critically.
The National Transportation Safety Board investigated, and determined the ramp’s design and lack of warning signs contributed to the accident. The board called the accident the worst highway disaster it had seen.
The project is described as a seismic retrofit of the southbound off ramp that curves over Marina Vista and Waterfront Road and adds a one-lane emergency access lane that connects southbound I-680 with northbound I-680 so that emergency vehicles will have an alternate route in case of disasters that block other ways.
Because I-680 is designated as a California Lifeline Route, the freeway and its bridges need to remain open after a natural disaster, such as an earthquake.
“We built the emergency connector lane because the northbound bridge of the Benicia Bridge is the newer bridge,” Amsk said. “If one event closed southbound I-680, now we’ll have a connector.”