Transform is committed to stopping highway expansion. In a time of extreme climate crisis, we can’t afford to build infrastructure that bakes in decades of further warming and undercuts our public and active transportation investments. Unfortunately, Caltrans District 4 and the Contra Costa Transportation Authority are planning to do just that on Interstate 680.
Transform dug into the Draft Environmental Impact Report (DEIR) and found major flaws in both the transportation analysis and the proposed environmental mitigation.
No Viable Express Lane Conversion Proposed
The proposed project runs northbound I-680 near Walnut Creek, with stated goals of reducing congestion, preventing bottlenecks on the corridor, and fixing the 7.5-mile gap in the existing northbound I-680 managed lane system between Livorna Road and SR-242. Transform supports the goal of a complete regional express lane network to better manage traffic congestion in the Bay Area, but there is no technical reason why this cannot be accomplished by converting existing lanes rather than through highway expansion. Yet, three of the four build alternatives purport to “close the gap” in the regional express lane network, despite actually increasing highway capacity. The only proposal that did not include a lane expansion does not complete the express lane network and seems to be designed to fail.
Express lane expansions induce demand
Induced demand is the concept that building more road capacity doesn’t decrease congestion and may increase traffic jams. It’s the “build it and they will come” of highway engineering, a well-documented phenomenon that has been widely known for decades. While express lanes can reduce congestion and better manage traffic, according to Caltrans HQ, building a new express lane creates the same increase in vehicle miles traveled as a new general-purpose lane. Additionally, studies of other express lane projects in the Bay Area have shown that high-occupancy and express lanes create the same amount of added vehicle miles traveled (VMT) as a general travel lane.
Despite the fact that Caltrans is framing this project as something that will “reduce bottlenecks,” the reality is that it will add lanes and increase car travel at a time when we should be reducing them.
Transform strongly objects to any alternative that expands the highway. In addition to the environmental impact and lack of efficacy to achieve the project’s goals, building new highways is expensive, with a price tag of up to $463 million. At a time when active transportation is severely underfunded and our transit systems face the fiscal cliff, there are much better uses of that money.
Faulty VMT Mitigation
Following the passage of SB 743 (Steinberg, 2013), VMT increases from highway capacity expansion should be analyzed, avoided, and/or mitigated. When done well, VMT mitigation measures, which range from transit service and biking improvements to affordable housing construction and road pricing, can be an effective means of alleviating the environmental harm of highway capacity projects. However, not only did Caltrans use faulty methodology that underestimated the increase in VMT, but its mitigation methods are unlikely to actually address the problem.
The NCST Induced Travel Calculator is the gold standard for VMT mitigation. But instead of simply using the model Caltrans HQ itself recommends, the DEIR uses a county-scale
travel demand model that ignores other trips in the region that travel behavior theory suggests, and evidence has shown, would increase due to expanded highway capacity.
Furthermore, the proposed VMT mitigations — a new express bus service with six buses in the fleet, shared mobility hubs at three locations, and an expanded countywide transportation demand management (TDM) program — only offset the full added VMT in two of the build alternatives, and even then fail to account for a backfilling effect where express bus service reduces cars on the road, encouraging additional trips due to the temporarily reduced congestion. Finally, full funding and implementation of these three mitigation
measures is “currently uncertain,” and it is “uncertain whether these programs would extend
beyond the Project’s Design Year (2047).” But after 2047, the highway expansion will still be there, continuing to increase VMT and emissions without any mitigation.
Transform supports congestion reduction, but it’s time for Caltrans to stop hiding behind junk science and develop true solutions to the Bay Area’s traffic problems.
Read Tranform’s full comment letter.