PLACERVILLE, Calif. — The long-awaited Mosquito Road Bridge has reached its ceremonial opening day in El Dorado County.
But if you were planning to be among the first drivers across the new span Friday, there is one important detail to remember:
The bridge is not open to public traffic until Saturday, Sept. 26.
El Dorado County is holding its official opening celebration Friday at 10 a.m. to mark completion of the massive replacement project. The ceremony represents the culmination of years of planning and construction on a critical connection between the Placerville area and the Mosquito and Swansboro communities.
For motorists, however, Saturday is the day that matters.
Ceremony Friday. Traffic Saturday.
The distinction is important because images and video from Friday’s celebration could easily give the impression that the bridge has already opened to regular traffic.
It has not.
According to the county’s Department of Transportation, the new bridge will be available for public use beginning Saturday, Sept. 26.
The new structure crosses the South Fork of the American River and replaces the historic one-lane suspension bridge that has served the area for decades.
The new crossing is approximately 1,200 feet long and carries two lanes of traffic. Its alignment also eliminates much of the steep, winding approach to the old bridge. County project documents indicate that the new alignment reduces the affected stretch of Mosquito Road from roughly 1.3 miles to about 0.3 miles.
For residents of Mosquito and Swansboro, that means more than a new piece of concrete and steel.
It changes the way they get home.
A bridge built for access — and emergencies
The old Mosquito Road crossing was narrow, winding and difficult for larger emergency vehicles to use.
County environmental documents identified the existing bridge as a single-lane timber suspension bridge only about 9 feet wide. Large emergency vehicles could not cross it and, when access was restricted, responders could face a detour of up to 20 miles using Rock Creek Road.
That made the replacement project particularly significant for a rural community where road access can become a matter of life and death during a fire, medical emergency or evacuation.
The new bridge provides a modern two-lane route designed to accommodate emergency vehicles while making the connection between the communities and the greater Placerville area considerably more direct.
El Dorado County’s Department of Transportation lists public safety and preservation of county infrastructure among its primary transportation priorities.
Replacing a piece of El Dorado County history
The crossing being replaced is not simply an old bridge.
It is part of the county’s transportation history.
The original Mosquito Road crossing dates to 1867. The existing suspension bridge was rebuilt in 1939 using the original foundations, according to project information.
For generations, residents have negotiated the narrow bridge and the twisting road leading to it.
The replacement project represents a fundamental change in that landscape.
County supervisors approved the project’s environmental review in 2017. In May 2022, the county awarded Shimmick Construction a $74.4 million construction contract. At the time, the county estimated the broader construction phase, including management, testing, design support and contingencies, at approximately $93 million.
The county maintains a dedicated project page with construction updates and project documents.
A final issue remains below the bridge
The opening comes as questions have also been raised about construction debris found along the South Fork of the American River beneath the new bridge.
Residents recently reported finding materials including rebar, metal pieces, plastic and other construction-related items in the canyon and river corridor. El Dorado County has acknowledged that some material fell below the bridge during construction and said the contractor is responsible for removing project-related debris.
El Dorado County Department of Transportation Director Rafael Martinez told the Board of Supervisors this week, “I have no doubt that, yes, some materials did fall down below.”
The county said it conducted an initial drone survey of the canyon and river corridor and was reviewing the footage. Officials also said a final inspection will be conducted before the project is formally accepted to determine whether additional project-related material remains.
That issue does not change the scheduled public opening, but it adds another chapter to a project that has already attracted considerable attention from residents who have lived with the old crossing for decades.
Saturday is the real opening
For those who have watched the Mosquito Road Bridge rise above the South Fork American River, Friday is the celebration.
For drivers, Saturday is the milestone.
Beginning Sept. 26, the new two-lane crossing is scheduled to carry public traffic and provide Mosquito and Swansboro residents with a modern connection to the rest of El Dorado County.
After years of planning, engineering, construction and detours, the ribbon-cutting is finally becoming a road.
And this time, residents won’t have to wait for the bridge to stop swinging before they cross it.
Sources: El Dorado County Department of Transportation; El Dorado County Mosquito Road Bridge project documents; Onsite Observer; KCRA 3.
