2 blocks of Gilman closed for roundabout work through June

This round of work is expected to last for about two months, Caltrans said. The whole project is slated to be done next year, "weather permitting."

2 blocks of Gilman closed for roundabout work through June
Caltrans is building two roundabouts on Gilman Street in West Berkeley to ease traffic woes. Caltrans

Caltrans has announced the closure of Gilman Street between Second and Fourth streets in West Berkeley for work related to two large roundabouts designed to ease traffic woes around the infamous intersections, which straddle I-80.

This round of work, which was set to begin Tuesday morning, is expected to last through late June, Caltrans said in a recent statement.

Access to businesses will be maintained and detours will be provided, Caltrans said.

Traffic will still flow in both directions on Second and Fourth streets, according to the statement.

The Gilman Street intersections where the roundabouts will be built have eight entry points on either side of the freeway, creating stress for motorists, cyclists and pedestrians alike.

Work has already been well underway on a new overcrossing south of Gilman Street to help cyclists and pedestrians cross the freeway.

That piece of the project began in May 2021 and is expected to be done this year.

The second phase of the project involves the actual construction of double roundabouts, one on each side of I-80.

Caltrans hopes to finish the roundabouts in 2024, "weather permitting."

The total project is estimated to cost more than $85 million, according to the latest projections from the Alameda County Transportation Commission (CTC).

More than half of that is slated to come from the state and another $30 million from Alameda County's Measure BB.

In 2018, project costs were estimated at $48 million.

The Alameda CTC opted for double roundabouts on Gilman Street because they are "proven to reduce serious accidents while providing increased capacity and improved traffic operations, as compared to a traffic signal with the same number of lanes," the agency said.

Traffic lights were considered in a series of studies that spanned nearly 16 years but were ultimately rejected: "All concluded that given the volume of traffic at the interchange and the number of intersecting roadways, an acceptable level of service could not be achieved with traffic signals."

Project work has been a collaboration involving Caltrans, the Alameda CTC, the cities of Berkeley and Albany, the East Bay Regional Park District, East Bay Municipal Utility District and various bicycle groups, according to the project page.

Watch: Gilman roundabouts video simulation

Curious about what it might be like to use the new roundabouts on Gilman Street in Berkeley? Caltrans created a video simulation.

Read more about the work on the Gilman interchange project page, which includes a list of answers to frequently asked questions. See Gilman Street detour information via Caltrans and the latest project factsheet.