Berkeley preview sheds new light on Gilman roundabouts

Members of the public got a look Wednesday night at plans to build two roundabouts at Gilman and Interstate 80. Photo: Emilie Raguso
Members of the public got a look Wednesday night at plans to build two roundabouts at Gilman and Interstate 80. A bike and pedestrian bridge — the U-shaped yellow line — is proposed south of Gilman. Photo: Emilie Raguso

Early plans to build two large roundabouts at Interstate 80 and Gilman Street in Berkeley were on display for the public Wednesday night at the North Berkeley Senior Center.

The project — with an estimated $24 million construction cost — is slated to be complete in 2022, a representative told the dozens of attendees who perused information stations set up around the room.

“This is an area that has a lot of concerns with it,” David Early, principal at Berkeley-based community planning firm Placeworks, told the crowd. “It’s quite a ‘wild west’ kind of scene.”

Scroll down to see a simulation of the proposed circulation.


By the numbers, the problem is stark. Crash data presented Wednesday, from 2011-13, showed significantly higher than average numbers of injury or fatal collisions, particularly on the north side of Gilman. On the west side off-ramp, those numbers were 80% higher than the state average. On the east side on-ramp, they were a whopping 177% above the state average.

South of the freeway, they were about 30% above the state average at both the on- and off-ramps.

The project involves the two roundabouts on either side of I-80, new sidewalks under the freeway, and a pedestrian and bike bridge similar to the one at Aquatic Park. Perhaps the most controversial elements of the project — in addition to the roundabouts themselves — are the location of the bike bridge, which makes a fairly large detour south before bringing users back up to Gilman, as well as plans to cut off access from Gilman to the frontage road on the east side of the freeway. 

Early told attendees that cutting off access to and from Eastshore Highway is necessary to make the roundabouts work and limit the number of vehicles that use them. There are plans to improve Second Street as an alternative route for motorists in the area, who will be able to use it to get to shopping destinations such as Target in Albany.

Early pointed to traffic studies that have shown the number of injury accidents around the freeway to be “somewhat higher than the statewide average,” adding, “We really do have an issue here with accidents.”

See some of the draft project materials.

He said there have been a number of past studies, going back to 1998, that all support what is essentially the same conclusion.


“All of them pointed at the fact that this is two sets of six-legged intersections that are very hard to take care of with traffic signals,” he said. The proposed solution? The roundabouts, which work by reducing “conflict points” among motorists and have been shown to reduce collisions, too, according to federal data on display Wednesday night.

Roundabouts work by reducing "conflict points" between motorists. Source: ACTC
Roundabouts work by reducing “conflict points” between motorists. Source: ACTC

Early said roundabouts work well because all motorists need to do is “look left for traffic.” They also shorten pedestrian crossings, slow down traffic and allow for more landscaping. He pointed to the Marin Circle as one example in Berkeley.

He described the new bike-pedestrian bridge as “another landmark crossing” across the freeway, which will eventually link up to the Bay Trail. As to its location, he said it needs to extend south because there are an extra 10-12 feet on either side of the freeway that will allow its construction without squeezing the bridge or losing capacity on the highway.

(Update, April 29: The location of the bike bridge, according to the project team, is also dictated by slope requirements from the Americans with Disabilities Act and the need to cross over an elevated section of I-80.)

“In addition to improving mobility through the Gilman street corridor, the project aims to close the gap in local and regional bicycle facilities through the I-80/Gilman Street interchange and provide access for bicycles and pedestrians traveling between the Bay Trail and North Berkeley,” according to information from the Alameda County Transportation Commission.

Caltrans, the Alameda County Transportation Commission and the city of Berkeley are working together on the project, with Caltrans designated as the lead.


David Early, of Placeworks, is helping run the community process related to the Gilman interchange project. Photo: Emilie Raguso
David Early, of Placeworks, is helping run the community process related to the Gilman interchange project. Photo: Emilie Raguso

A comprehensive environmental review, taking into account both state and federal analyses, will need to be completed, he said. That environmental review — including a public comment period — is expected to last through much of 2017, followed by final design review in 2018 and two years of construction, from January 2020 through January 2022.

Early said construction is expected to cost about $24 million, which has been set aside through Alameda County’s Measure BB, a half-cent sales tax approved by votes in 2014. The roundabout plans have actually been around for years but the money to pay for them only recently became available.

“There is funding already in place,” Early told attendees. “Once it’s designed and ready to be constructed it should be possible for it to be built.”

According to a March 2016 project factsheet, the total project cost is expected to reach nearly $34 million, with about $8.4 million “TBD” and $300,000 coming from the city of Berkeley.

People who could not attend the meeting should be able to submit feedback online on the project website in the near future, Early said shortly after publication. The Alameda County Transportation Commission has posted the boards from the session online. (Editor’s Note: This paragraph was updated after publication to reflect new information from the project team.)

See the I-80 Gilman Interchange Improvement Project website and more documents related to the project.

Related:
‘Double-roundabouts’ approved at Berkeley’s Gilman interchange (10.27.14)
Homeless move to railroad tracks after Gilman ‘clean-up’ (07.30.14)
West Berkeley Philz Coffee: Now officially open (07.29.14)
West Berkeley Whole Foods to open Nov. 4 (07.22.14)
Rodents, trash prompt city clean-up of homeless camp on Gilman; residents ‘scattered’ (07.18.14)
City of Berkeley gives Gilman Street homeless a reprieve (07.10.14)
Caltrans fence forces homeless to find new camp (04.10.14)
What’s happening with the Gilman Street Interchange? (02.22.13)

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