Traffic "Flushing" and Metering Planned for I-80 Freeway

Commute time on Interstate 80 through Contra Costa and Alameda counties – from the Carquinez Bridge to the Bay Bridge – is anyone’s guess. But that could be about to change, according to the local cities and agencies who have teamed up to tackle congestion on one of Northern California's busiest freeways.

The I-80 Integrated Corridor Mobility (ICM) Project plans to spend $93 million on freeway ramp metering and various incident management techniques to improve traffic flow and cut emergency response times along I-80 from the San Francisco-Oakland Bay Bridge Toll Plaza in Alameda County to the Carquinez Bridge in Contra Costa County. A full system roll-out is expected by the end of 2014.

The Continuing Problem of Congestion on Interstate 80

At an in Richmond, Hishami Noeimi of the Contra Costa Transportation Authority explained that there are an average of 2,200 accidents on the 19.5-mile Eastshore corridor of I-80 every year, around half of which are caused by congestion. The cycle of congestion, collisions and more congestion causes slower emergency response times, increased pollution and more delays. 

Three sections of I-80 were among the top 40 most congested freeway corridors in California, including the Bay Bridge and two stretches of the Eastshore Freeway. Combined, these most congested sections of the freeway caused 1.65 million hours of delay per mile to road users in 2010.

The freeway carries around 290,000 cars per day, with 22 cross streets providing freeway access along the corridor, and a total of 135 traffic signals. The busiest section of the freeway is in Berkeley, between Gilman and Powell Streets.

Facts About Eastshore Interstate 80

Past attempts to improve traffic flow along the I-80 corridor and San Pablo Avenue have included signal timing coordination and rapid bus service. The ICM project would update and enhance traffic signal responsiveness with "adaptive ramp metering" and install informational message signs to alert drivers to traffic problems. An expanded information network would also connect all the cities along the corridor, including Oakland, Emeryville, Berkeley, Albany, El Cerrito, Richmond, San Pablo, Pinole and Hercules.

How Adaptive Ramp Metering Works

Ramp metering has been in effect since the '60s, controlling the flow of traffic onto the nation's freeways at peak times to minimize the congestion and collisions caused by traditonal merging. "In every ramp metering deployment that I've seen, there has been a significant reduction in collisions," said Christina Atienza of the West Contra Costa Transportation Advisory Committee (WCCTAC).

But metering has not been without its problems. One of the biggest concerns from city officials about installing meters on I-80 ramps is the potential for queueing traffic to end up clogging surrounding streets. 

The ICM project tackles this problem with "adaptive" metering, Atienza explained.

"The metering rates will actually go faster if the queues extend beyond a certain point defined by your local traffic engineers," she said. "Once a queue hits a detector that is placed in that location, metering rates speed up so that it allows more cars to go through and prevents back-ups."

Ramps will still get overloaded sometimes — "it just happens," added Atienza — but the adaptive metering will help push through traffic until the ramp gains more capacity.

Metering is already in effect on I-580 in the Pleasanton/Dublin/Livermore area and on I-101 in San Mateo.

"Flushing" Traffic Along San Pablo Avenue

One of the focal points of the ICM Project is San Pablo Avenue, which runs parallel along the entire length of I-80 and is therefore used as an alternative route when the freeway is congested. The result is a surge of traffic onto city roads.

"As traffic diverts along San Pablo Avenue, the traffic signals along the local streets are not equipped to handle sudden increases in traffic," said Noeimi. "That results in gridlock."

Signal synchronization and responsive timing will help to "flush" this traffic through San Pablo Avenue quicker, according to the project developers, by extending and coordinating green lights during peak traffic times.

What do you think of the plan to "flush" traffic along San Pablo Avenue? Take the poll at the bottom of this page.

The project also plans to direct drivers back to the freeway as quickly as possible. Traffic that diverts to San Pablo tends to stay on there, according to Noeimi, since drivers are unsure when they have passed the knot of traffic on the freeway. The ICM project will install informational "trailblazer" signs along the length of the street to inform drivers when to get back on I-80.

Community members expressed concern that "flushing" traffic along San Pablo Avenue will cause problems for drivers trying to cross San Pablo. The project leaders confirmed that, yes, there will be additional delay for the cross streets to accommodate heavier traffic on San Pablo. However, local agencies will help to ensure a balance on cross streets with a high demand.

"The intent of the project is to benefit everyone, not to make some segment of the population bear an undue burden," said Atienza.

Who's Paying and Who's Taking Responsibility for the Project?

The 93-million project will be funded by federal, state and local tax revenues, with the bulk, $53 million, from California's Corridor Mobility Improvement Account. Almost $5 million will come from Contra Costa County's Measure J. 

El Cerrito City Councilwoman Janet Abelson, who is also vice chair of the WCCTAC board, made clear to attendees of Monday's open house that the project will not result in any financial burden for the collaborating cities.

"Our cities will not be responsible for operation or maintainance," said Abelson. "We do not have the money."

The full I-80 ICM Project proposal is available online on the California Department of Transportation website for District 4.

Among the various agencies involved in the project, Caltrans is taking the lead on environmental compliance, the Federal Highway Administration is in charge of project oversight, and the Alameda County Transportation Commission is implementing the project. Partners include the Metropolitan Transportation Commission, the Contra Costa Transportation Authority and WCCTAC, as well as the nine cities impacted by I-80. 

Interested in updates on the I-80 ICM Project? Click "Keep me posted" below. 

You can prepare for your commute by checking live traffic conditions on the El Cerrito Patch traffic map.