Officials to replace Old Highway 30 bridge

Posted at 1:45 PM, Feb 23, 2016
and last updated 2016-02-23 15:45:02-05

Canyon Highway District No. 4 is looking to replace what has been known over the years as the Old Highway 30/West Plymouth Street Bridge, off Interstate 84, at Exit 26 in Caldwell.

The existing one-lane bridge crosses the Boise River, providing local access to the river and surrounding neighborhoods. It is also a link between Caldwell and the Middleton area. This route has been used as a bypass to Interstate 84.

The current steel truss bridge is a three-span, 388-foot long structure constructed in 1922 and currently carries 1,350 vehicles a day, including buses and trucks. The existing bridge needs to be replaced due to its narrow width and poor, aging condition, Highway District officials said.

The bridge is beyond its functional lifespan and needs to be replaced, they added. The existing structure is proposed to be converted into a pedestrian pathway as part of Caldwell’s Boise River Greenbelt.

The general work will bring about a new bridge, bridge-approach roadway, and pathway relocation.

The District plans to convert the existing bridge into a bicycle and pedestrian pathway. Proposed improvements include a new concrete deck and pedestrian railing. The approach will also allow separation of pedestrian/bicycle traffic from vehicular traffic providing for a safer pathway system, the District said.

They said improvements will provide a safe route for vehicles, bicycles and pedestrians.

The Old Highway 30 Bridge, designed by Caldwell City Engineer F. H. McConnel was built in 1922 by the American Bridge Company, which was a subsidiary of United States Steel, who also built famous structures like the Woolworth Building, the Chrysler Building, the Empire State Building, the Sears Tower and the San Francisco Bay Bridge.

At that time, the bridge was called the Boise River and Canal Bridge, and at construction was part of the Idaho Pacific Highway that later became U. S. Highway 30. It continued to be called U. S. Highway 30 until the early 1960s, when the nearby Interstate was constructed and the southeast portion of the roadway was renamed Plymouth Street, while the northwest side was renamed Old Highway 30. 

Canyon Highway District 4 and the City of Caldwell will use multiple communication tools to gather public input and assess concerns of the local community, including web and social media support, public open house meetings, and project update newsletters.

Two open house meetings will be scheduled sometime in the next several months to introduce the project to the public and gain input from the residents in the area.