Geometric Design & Traffic

The Oakland Alameda Access Project area is located in a dense, heavily developed residential and commercial urban environment. Currently, during peak commuting periods, traffic is heavy, and mobility is poor.

Traveling between Alameda and Oakland often results in long lines within the Webster and Posey Tubes. Traffic backs up on surface streets waiting to enter or leave the tubes. Getting on and off the freeway also means driving in large loops along surface streets through local neighborhoods.

Major Project Features - Oakland

There is no perfect solution to the challenges presented by the area’s current conditions. But the Oakland Alameda Access Project includes many ways that traffic and circulation can be improved for vehicles traveling between Alameda, downtown Oakland, and Chinatown.

The Oakland Alameda Access Project will reduce street congestion from freeway on-and-off traffic and improve safety for residents in the neighborhoods adjacent to the freeway and for motorists on local streets traveling through the area.

Major Project Features - Oakland

LEGEND

Travel Time: Posey Tube to NB I-880 (am)

Existing and Future Traffic Conditions

Traffic analyses have been performed for the opening year (2025) and future (year 2045) timeframes, under two scenarios. The “Build” scenario describes the conditions when all proposed project features are in-place. The “No-Build” scenario describes the conditions if nothing is done to improve the project area.

The following are some highlights from the traffic analyses:

Travel time in the Posey Tube: If the project is not built (No-Build), by 2045, it would take six minutes to travel through the Posey Tube to I-880 during the morning commute. If the project is built (Build), it would take a little less than four minutes representing a savings of over two minutes.

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Travel Time: Posey Tube to NB I-880 (am)

NB I-880 to Webster Tube (pm)

Travel times to the Webster Tube: During the evening commute, if the project is not built (No-Build), traffic to the Webster Tube will back up even worse than current conditions. It will take up to eight minutes longer along various routes from northbound I-880 to get to the Webster Tube, compared to conditions if the project is built (Build).

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NB I-880 to Webster Tube (pm)

Northbound I-880 Average Speed

Average Speed on Northbound I-880: Average traffic speeds on northbound I-880 through the project limits are expected to decrease by less than 2 mph during the morning peak period in the worst case. The average speed for the No-Build and Build during peak period will be around 45 miles-per-hour (mph) in 2025 and reduce to around 30 mph by 2045.

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Northbound I-880 Average Speed

Northbound I-880 Vehicle-Hours-Traveled

Vehicle Hours Traveled: Vehicle hours traveled along I-880 will increase if the project is built due to removal of the northbound I-880 off-ramp to Broadway and the improved connection to the Jackson on-ramp under the Build scenario. These changes will result in higher demands for the segment of freeway between the Jackson Street on-ramp and the I-980 off-ramp. This segment is expected to operate at capacity for the No-Build and Build alternatives. Higher demands under the Build alternative lead to additional congestion and queuing.

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Northbound I-880 Vehicle-Hours-Traveled