Battling Bottlenecks on I80
Caltrans plans congestion-busting measures between Dixon and Sacramento

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The I80 over the Yolo Basin.

March 31, 2020: No matter where you come from in the Greater Sacramento region, you know that sinking feeling as you approach the sea of brake lights on the causeway over the Yolo Bypass. As transportation reporter Tony Bizjak joked in the Sacramento Bee, “it’s become a major pain in the bumper.” 

The key reason the freeway between West Sacramento and Davis is so often jammed is high demand: more people want to drive that route than it can smoothly accommodate. The best solution is to give all those travelers more options to get where they want to go. This includes giving people better transit options, better bike and walking options, and making more efficient use of the space on the freeway. 

That is why Caltrans plans to increase the ”person throughput” of that stretch of I80 by creating additional capacity in each direction. This will be in the form of “managed” lanes, meaning they could be designated as bus/carpool lanes (High Occupancy Vehicle/HOV) or converted to toll lanes.  

The High Occupancy Toll (HOT) lanes could be priced dynamically so that solo drivers could buy their way into the lane, with the cost of access depending on the level of congestion. Preliminary modeling shows the addition of an HOV lane through the corridor would result in a 53 percent reduction in delay during the morning peak and a 38 percent reduction in the evening peak. 

“There is no question something needs to be done,” said Lucas Frerichs, a Davis city councilmember who chairs the SACOG board. “The issue with traffic backups every day in both directions results in valuable time loss for people going to work and school and a major impact on quality of life. It affects goods movement as well.”  

 Caltrans manager for the Yolo 80 Corridor Improvement Project Jess Avila explains that I-80 is the primary freeway for people and freight between Northern California and the east coast. Locally, it serves commute traffic, travel to and from the San Francisco Bay Area, recreational trips to and from Lake Tahoe, and is a primary corridor for freight going east from the Port of Oakland, as well as north and south on the I5 or SR99.  

At the evening commute peak, average travel times going east are twice those of free-flowing traffic, with less severe congestion in the morning westbound commute. But accidents and heavy Tahoe traffic mean the corridor can also be jammed at other times. 

Caltrans’ Yolo 80 Corridor Improvement Project outlines six options to increase the capacity of the freeway through Yolo County. Most options envision an additional lane in each direction but the cheapest alternative calls for just one reversible lane that can be switched from westbound in the morning to eastbound in the afternoon. 

The project’s study report highlights 10 choke points along the 21-mile stretch of the corridor and cites the need to improve HOV access for Yolo Bus, Solano Transit, and the Causeway Connection service of electric buses between the UC Davis campus and UC Davis Medical Center in Sacramento, which begins on April 6. It also highlights the need for better bike and walking options on the corridor. Access to the walk/bike bridge is challenging, meaning it is little used, and options include replacing or widening it. 

Avila said the project’s schedule is a moving target because it depends on funding, but current plans have it beginning construction in spring 2025 and open to traffic late 2027/early 2028. 

The six options range from $100 million to $600 million. The most expensive plan would add a “standard” 12-foot lane with 10-foot shoulders in each direction along with a couple of “big ticket items,” said Avila: a new 3.4-mile bike/ped bridge over the Yolo Bypass and a managed lane to managed lane connector, which would be “new construction threaded through the existing WB80 to EB 50 connector.” Cheaper alternatives use narrower lanes and fewer options, down to the one reversible lane at $100 million. 

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