Caltrans Weighs $12.35 Million Highway 99 Intersection Improvements Near Biggs
Public Input Requested
October 15, 2026 | Gridley Media Group
Reporter: Alison H. Rankin
A proposed $12.35 million highway safety improvement project could bring significant changes to the intersection of State Route 99 and Rio Bonito Road near Biggs, where the California Department of Transportation (Caltrans) is considering installing either a roundabout or a traditional traffic signal.
Caltrans District 3 is evaluating both alternatives in response to a documented history of traffic collisions at the intersection, with potential impacts on local residents, commuters, commercial truck drivers, agricultural operators, and emergency vehicles traveling through the area.
Caltrans presented the proposal to the Biggs City Council on Tuesday, October 13, 2026, as part of the project's ongoing planning and environmental review process. Neither a roundabout nor a traffic signal has been selected as the final design, and Caltrans is requesting public feedback while the project remains under consideration. The project is identified as Caltrans Project Number 03-0N010 and State Highway Operation and Protection Program (SHOPP) ID 24125.
Collision History and Proposed Safety Improvements
According to Caltrans, the intersection experienced 15 reported traffic collisions between April 1, 2019, and March 31, 2024, resulting in eight injuries. The agency reports that all 15 collisions were broadside crashes associated with drivers failing to yield the right-of-way.
Information presented to the Butte County Association of Governments (BCAG) in October 2025 also indicated that the intersection's collision average was more than three times the statewide average. Broadside collisions, commonly referred to as T-bone crashes, occur when the front of one vehicle strikes the side of another and can be particularly dangerous because the sides of passenger vehicles generally provide less space to absorb an impact than the front or rear.
Caltrans is studying two alternatives intended to reduce the number and severity of future collisions. The first involves constructing a roundabout, requiring approaching motorists to reduce their speed and yield to vehicles already circulating through the intersection, while the second involves installing a conventional traffic signal to regulate vehicle movements using red, yellow, and green lights.
Preliminary roundabout concepts described in BCAG's October 2025 meeting materials included a single-lane design with a 20-foot circulating lane, a 16-foot truck apron, raised splitter islands, traffic signs, and advance warning beacons. A truck apron is a specially designed portion of a roundabout that provides additional maneuvering space for larger vehicles. The traffic signal alternative described in those materials included intersection lighting and possible utility pole relocation. Both alternatives remain subject to further engineering analysis, environmental review, and design development.
Community Concerns and Potential Traffic Impacts
The possibility of constructing a roundabout has prompted concern from at least one community member who contacted Gridley Media Group requesting coverage of the proposal. The individual expressed opposition to installing a roundabout and encouraged greater public awareness of the project, although the extent of broader community support or opposition has not yet been established.
State Route 99 is an important transportation corridor connecting rural communities throughout the Sacramento Valley with larger population centers. According to Caltrans, the highway serves residential, commercial, agricultural, and recreational traffic. For communities such as Biggs and Gridley, the ability of larger vehicles to safely navigate the intersection is an important consideration, particularly for agricultural equipment, commercial trucks, emergency vehicles, and everyday commuter traffic.
Although preliminary roundabout plans include a truck apron intended to accommodate larger vehicles, the final dimensions and operational requirements have not yet been established. Other considerations include potential traffic delays, turning movements, vehicle speeds, and access to surrounding roads and agricultural properties. The project website provides general information about both alternatives, but detailed comparative traffic modeling results are not included in the publicly available project overview. Additional engineering analysis will help determine how the proposed designs could affect traffic flow and intersection operations.
Project Funding, Local Government Involvement, and Construction Timeline
Caltrans currently estimates the total cost of the Highway 99 and Rio Bonito Road safety improvement project at $12,350,000. The California Transportation Commission approved the project to begin development on June 26, 2026, with funding provided through the State Highway Operation and Protection Program, which supports improvements to California's existing state highway system.
Earlier regional transportation planning materials identified a traffic signal as a proposed improvement for the intersection, while the current project is evaluating both a roundabout and a traffic signal. The publicly available Caltrans project overview does not provide separate cost estimates for each alternative, meaning the $12.35 million figure represents the estimated cost of the overall project rather than the confirmed construction price of either design.
The proposal has been discussed with regional and local government agencies throughout its early development. According to Caltrans, representatives met with local agencies on October 2, 2025, before presenting an overview to the BCAG Board of Directors on October 23, 2025. Caltrans finalized its Project Initiation Report on May 1, 2026, and following approval by the California Transportation Commission in June, the project entered its Project Approval and Environmental Document phase in July 2026.
Most recently, Caltrans presented the proposal at the Biggs City Council meeting on October 13, 2026. As of October 15, approved minutes from that meeting were not yet available through the city's published meeting records reviewed for this report. Statements made by individual council members, public comments presented during the meeting, and any positions expressed regarding the alternatives have therefore not yet been independently confirmed. Caltrans identifies BCAG, Butte County Public Works, and the City of Biggs as agencies involved in local coordination.
According to Caltrans, the anticipated project schedule includes the release of a Draft Environmental Document in summer 2027, followed by a 30-day formal public comment period and public open house, with dates and location to be announced. Completion of the Project Approval and Environmental Document phase is targeted for fall 2027, with final engineering and design plans expected between fall 2027 and fall 2028. Advertisement and award of the construction contract are anticipated between fall 2028 and spring 2029, with construction tentatively scheduled from spring through fall 2029.
During environmental review, Caltrans will conduct technical studies, evaluate potential environmental impacts, identify mitigation measures where necessary, and work toward selecting a final design concept. Additional coordination may be required for right-of-way arrangements, utility adjustments, and environmental permits. The schedule remains preliminary and may change as the project advances.
Public Input Requested — How Residents Can Participate
Caltrans is encouraging residents, commuters, agricultural operators, commercial drivers, and others familiar with the Highway 99 and Rio Bonito Road intersection to participate in its public engagement process. The agency has established an online project page where community members can review information about the proposed improvements, learn about roundabouts and traffic signals, access project documents, and complete a survey to share their experiences, concerns, and opinions.
Official Caltrans Public Survey: https://engage.dot.ca.gov/03-0n010#tab-83230
Full Project Information: https://engage.dot.ca.gov/03-0n010
If the direct survey link does not open the questionnaire, residents can select the Survey tab on the project page. A separate formal public comment period is anticipated for summer 2027 following the release of the Draft Environmental Document. The online survey provides an opportunity for public feedback and does not constitute a binding vote on the final intersection design.
What Happens Next?
The proposed improvements could represent a significant transportation change for motorists traveling through southern Butte County. While Caltrans has documented a history of collisions at the intersection and identified a need for safety improvements, questions remain regarding which alternative would best address the safety concerns, how each design would accommodate agricultural and commercial traffic, what the individual alternatives would cost, and how construction could affect local travel.
These considerations will be evaluated as the project advances through technical studies, environmental review, and design development. With the final intersection design still under consideration, residents have an opportunity to review the proposal and provide feedback before the project moves into later development stages.
Gridley Media Group will continue following the Highway 99 and Rio Bonito Road Safety Improvement Project, including future Caltrans announcements, Biggs City Council discussions, project developments, and opportunities for public participation.
Residents are encouraged to review the official project information and share their perspectives directly with Caltrans.
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