Freeway planning in California is shifting gears. If the past was adding lanes to reduce congestion, the future is about creating multimodal mobility corridors. At least that is the thinking as the Contra Costa Transportation Authority (CCTA) seeks to improve mobility in their I-680 Corridor, which includes closing a key gap in the region’s express lane network.
The SB 743 Effect
A big reason for the shift is Senate Bill 743, which requires cities, counties, and other lead agencies to rethink the way they plan and deliver projects. Lead agencies can no longer simply rely on road expansion (like an expanded express lane network) to solve traffic congestion. Instead, they must measure vehicle miles traveled (VMT) rather than level of service (LOS) to assess a transportation project’s impact under the California Environmental Quality Act (CEQA).
The new VMT impact assessment aligns with California’s many climate, health, and equity initiatives to encourage active transportation, diversify land use around transit, deliver cleaner air, and drastically reduce the levels of climate-warming pollutants. It will also prompt agencies to invest in cleaner modes of transportation and require the implementation of VMT mitigation strategies when a project is expected to increase miles traveled.
Completing an Express Lane Network
CCTA is delivering one of the first major projects to be affected by the new policy. CCTA’s I-680 Express Lane Completion project will address the northbound express lane gap along an eight-mile stretch of freeway between the cities of Alamo and Concord.
The project area includes a junction with the east-west State Route 24 which connects major junctions in Oakland with inland cities. The north end of the corridor also connects to State Route 242 (SR-242), where the existing northbound High-Occupancy Vehicle (HOV) lane would be converted to an express lane.
The cost of the project is $310 million. But closing the gap will play a major role in increasing travel speeds for carpools and other qualified vehicles and improving operations on this critical span of I-680. The plans fall under CCTA’s INNOVATE 680 program, which aims to minimize corridor-wide congestion and improve mobility and access to transit using integrated technology and greener, more efficient transportation strategies.
CCTA is working with Caltrans to finalize its environmental study of design alternatives for this express lane. Strategies for closing or reducing the gap include lane realignment, lane addition, HOV lane conversion, and general purpose (GP) lane conversion. Another less familiar strategy is a braided ramps system that will untangle a complex set of existing on- and off-ramps that cause conflict as cars exit and enter the highway within a short span. While lane realignment, HOV lane conversions, GP lane conversions, and braided ramps do not impact VMT, lane additions do. Because lane additions are featured in three of the four build alternatives under consideration, mitigation efforts are required. In fact, any increase in VMT is considered significant and must be fully mitigated.
Mitigating the Impact
CCTA teamed up with Caltrans to quantify the amount of induced VMT and identify potential mitigation measures. More than a dozen mitigation options were evaluated. They ranged from a two-way cycle track to land use mitigation (a 97-unit affordable housing development already proposed less than half a mile from a BART station and near regional trails). Through extensive research and analysis, Caltrans and CCTA found that the following options could be effective in mitigating the project’s induced VMT:
- I-680 Shared Mobility Hubs – enhancing three transit stops or stations to improve access to express bus stops along the corridor
- I-680 Express Bus Service – implementing express service connecting multiple transit stations to address a gap in the rail network and improve bus service efficiency
- Expansion of 511 Contra Costa – expanding CCTA’s Transportation Demand Management (TDM) program, which includes incentives such as free transit passes, carpool rewards, and e-bike rebates
Is This Costly Freeway?
While the results of these evaluations are promising, studying the possible VMT increases and implementing the subsequent VMT mitigation strategies come at a cost. In addition to the significant capital construction costs of the alternatives being evaluated, VMT mitigation could cost the agency another $136 to $143 million–which is almost half of what the base project costs.
The gap closure project has been split into two phases, and 36% of construction funding for Phase 1 will be covered by local, state, and federal funding. The remaining funding has yet to be secured. The following table summarizes the proposedExpress Lane Completion alternatives, their potential increase in VMT, and estimated mitigation and capital costs.
Or Well-Priced Corridor Solution?
Although $140 million in mitigation sounds like a lot, it’s worth taking a closer look at the proposed mitigation. The key elements were projects within the same corridor that were also a part of CCTA’s long-term plan—just more difficult to fund. As a result, the project is probably better described as a comprehensive corridor mobility project that includes multiple modes to get people where they want to travel.
If planning agencies adopt this new mindset and begin to think more holistically about the corridor when developing new projects, this may very well be the future of freeway planning in California: making road improvements that are in sync with other mobility options, tying in options that benefit both the community and the environment.
The Road Ahead
CCTA is confident the long-term gains of the Express Lane Completion project (congestion relief, system continuity, and operational improvements) far outweigh short-term headaches like increased project costs and an expanded delivery schedule, and they are already viewing projects with a “future of freeways” mentality. “For years CCTA has been championing fast, reliable, and accessible alternatives to driving within the corridor,” says Executive Director, Timothy Haile. “With SB 743, we now have greater opportunities to fast-track some of our most innovative and environmentally friendly projects—we’re eager to move these three VMT-mitigating projects forward.”
In addition to finding ways to reduce VMT for the I-680 Express Lane Completion project, CCTA is also lending its expertise to the State’s SB 743 Implementation Working Group to provide thought leadership on VMT mitigation. The agency is excited to lead the way and help to improve the future of freeways, by providing healthy, sustainable, and connected transit options for residents of Contra Costa County and beyond.