Myths and Facts about Impacts of Freeway Lane Expansions on Traffic Congestion and Adoption Rates of Electric Vehicles

By Alan Pryor

Executive Summary

Proponents of the proposed DISC project claim that the projected traffic congestion associated with the project will be solved soon in the future by the hoped-for I-80 freeway HOV lane expansion easing roadway congestion. The proposed freeway expansion project envisions the addition of one HOV lane on each side of the I-80 freeway freeway from from Hwy 113 on the west to the I-5/I-50 interchange in Scaramento and the I-80/Reed Ave interchange to the east.

Proponents also claim that the associated vehicular greenhouse gas (GHG) emission from the increased traffic to and from the DISC site will be substantially eliminated by the mass adoption of electric vehicles reducing tailpipe GHG emissions

Unfortunately, science shows us that the proposed addition of the two HOV lanes on the 20.8 mile stretch of the I-80 freeway expansion (one HOV lane on each side of the freeway) will actually induce further traffic and Vehicle Miles Traveled (VMT) on this stretch of the freeway. Methodology developed by the UC Davis National Institute of Sustainable Transportation (NIST) shows this phenomena is due to both short and long-term driver behavioral changes including taking longer and more frequent automobile trips, route shifts, and transportation mode shifts away from public transportation. The cumulative impacts will result in no relief from the current plague of I-80 freeway congestion.

Further, mass adoption of electric vehicles will take decades to substantially replace existing aging fossil fuel-powered vehicles resulting in no near term decreases of the additional GHG emissions resulting from new traffic associated with the DISC project. These emissions directly threaten the Davis goal of carbon neutrality by 2040 and Yolo County's goal of net negative carbon emissions by 2030.

Myth #1 – The Proposed I-80 Expansion will Greatly Reduce Freeway Congestion for DISC Commuters Leading to Decreased Congestion for Local Drivers on Mace and Covell Blvd.

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The following comments were shared with the Natural Resources Commission at its meeting last night and are reposted here with permission of the author.

This is Alan Pryor speaking as a former 12-year NRC Commissioner. I think it's telling to review a comment made by a Planning Commissioner at a hearing on this project last year.

"You want this to be the most sustainable, innovative tech campus in the United States. But you have come to us with a car-dominated, auto-centric proposal on the edge of town, far from the capitol corridor station, not linked to good transit, with huge parking lots and parking structures. Widening Mace to accommodate more traffic is not the answer. It's going to induce more traffic."

Nothing has functionally changed with this project since then except its size is been reduced by less than half but the applicant is now proposing transportation features that are even less conducive to non- automotive forms of transportation.

For instance the applicant is now refusing to construct the previously agreed upon off-grade crossing to allow arriving pedestrians and bicyclists to safely cross six lanes of Mace Boulevard during rush-hour traffic. How is that possibly welcoming to bicyclists and pedestrian employees arriving on the west side of the street or to school kids living at the project trying to get to school and back each day without a parent driving them.

Also, the original proposal was an environmental nightmare in that it projected over 83,000,000 lbs of CO2 equivalent emitted each year. The new estimate is about  45,000,000 lbs of CO2 equivalent per year – or about 4.5% of the City's current carbon footprint for this one project alone. All of these emissions would have to be later eliminated for the City to reach carbon neutrality by 2040 but the developer has not proposed how they will do this.

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