SR-39 Reopening Project

Location and Limits

This project is located on State Route 39 (SR-39), from post mile (PM) 40.0 to 44.4; it is in the Angeles National Forest, near the City of Azusa, in Los Angeles County. Currently, this 4.4-mile segment of highway is closed to the general public but is accessible for emergency vehicles and maintenance crews.

The Project

State Route-39 (SR-39) is a two-lane highway connecting the San Gabriel Valley to the Angeles Crest Highway. Caltrans proposes to rehabilitate and reopen a 4.4-mile segment of SR-39 from post miles 40.0 to 44.4, within the Angeles National Forest, in Los Angeles County. The restored connection could be accessible to public highway traffic throughout the year, with seasonal closures during times of inclement weather. The proposed project would reconstruct the 4.4 mile stretch of roadway by installing roadway features to prevent future slides from damaging the roadway. There are currently six (6) proposed alternatives under consideration for this project:

Alternative 1 - No-Build

The ‘No-Build Alternative" proposes to maintain the existing conditions of the roadway without any improvements.

Alternative 2 - Evacuation Route (Minimum Build)

This alternative proposes limited roadway restoration. Access to the roadway would be strictly for emergency service responders and maintenance access. The roadway would continue to be closed to public highway traffic.

Alternative 3 - Active Transportation Access (Shuttle and bicycle path facilities)

This alternative proposes to restrict access to the roadway to recreational related activities (e.g., enjoying vista views, hiking, biking, picnicking, camping, fishing, etc.) and allow only onsite shuttle service to operate and ferry national forest visitors through the restricted roadway adhering to a maximum speed of 15 mph and exercising extreme caution at well-marked wildlife crossings. This alternative also proposes two sustainable public parking areas (at PM 40.0 & PM 44.4) to be constructed for visitors to park their vehicles and bikes. The main structural features include 1 major viaduct structure, two rock-sheds, and six soldier pile retaining walls.

Alternative 4-Full Opening

This alternative proposes to rehabilitate and reopen the closed segment of SR-39 to public traffic and provide unrestricted access and a through-traffic connection between Interstate-210 (Foothill Freeway) and State Route-2 (Angeles Crest Highway). A roundabout feature is also proposed at the SR-2/SR-39 intersection. No parking lots are proposed for this alternative. The main structural features include 1 major viaduct structure, two rock-sheds, four viaduct/wildlife crossing structures, and six soldier pile retaining walls.

Alternative 5 - Viaduct Construction

This alternative proposes to construct a 4.4-mile-long standard two-lane elevated viaduct structure adjacent to the existing roadway. The continuous elevated viaduct would bypass the slide area, connect SR-39 to SR-2, and allow wildlife, slide debris, and water runoff to pass underneath the highway. The proposed bridge section would consist of a 10-foot-wide outside shoulder and a 12-foot-wide lane in each direction. This alternative would restore public highway traffic connecting SR-39 to SR-2.

Alternative 6 – Single Travel Lane

This alternative proposes to construct a single travel lane having a total roadway width of 20 feet (12-foot travel lane with a 4-foot-wide shoulder on each side of the travel lane).  The lane would be shared by all traffic with room to pull over and allow on-coming vehicles to pass safely.


This segment of SR-39 has been closed to public highway traffic since 1978 as the roadway is regularly damaged by landslides, flooding, falling rocks and forest fires. In February 2003, the closed highway was opened to emergency crews after a Caltrans study showed reopening it would not harm wetlands, air and water quality, natural vegetation or threatened plants and animals. Maintenance activities have included the cleaning of drainage culverts and the erection of a dirt berm. With these past improvements, the roadway is passable, but only open to emergency service vehicles, and it is constricted as it approaches its northerly terminus. The proposed project will reconstruct the 4.4 mile stretch of roadway by installing roadway features to prevent future slides from damaging the roadway.


4.4 miles


The purpose of this project is to restore access and provide a through-traffic connection between Interstate-210 (Foothill Freeway, or I-210) and State Route-2 (Angeles Crest Highway, or SR-2), in order to enhance access for fire suppression forces, search and rescue, and emergency response personnel, including the USFS and the Los Angeles Sheriff’s Department. It also aims to improve the safety and operation of the roadway, while preserving the integrity of the existing facility. Consistent with Caltrans’ Complete Streets policy (DD 64-R2), this project would also improve access for patrons of the numerous recreation areas within the Angeles National Forest and provide an economic benefit to the forest and local businesses. All of this would be done in a way that avoids impacting the endangered bighorn sheep that utilize the area.

The need for this project is based on the poor and degrading condition of the existing roadway on this segment of SR-39. The current conditions continue to degrade and may pose a safety hazard to maintenance crews and other users of the facility. Restoring and reopening the closed segment of SR-39 is also needed to bring this roadway into compliance with the California Streets and Highway Code, Section 91 and 100 which mandates that Caltrans shall improve and maintain state highways as provided in code, and that Caltrans shall monitor the cumulative impacts of fragmented gaps in the State Highway System (SHS) to identify safety and long-term maintenance issues. With the implementation of the proposed project, the safety concerns would be resolved via rehabilitation of the roadway and its appurtenant facilities. A regional traffic circulation connection would also be restored in the reopening of this segment of SR-39 to provide enhanced access for the Los Angeles County Sheriff’s Department and other emergency personnel during search and rescue activities and in reducing response times.

Scoping Meeting Information

Date: December 15, 2022

Time: 6:30 p.m. to 8:00 p.m.

Meeting Recording

Presentation Slides

Comment Period

December 15, 2022 to January 16, 2023

How to submit comments

Comments may be submitted and voiced at the Public Scoping Meeting on December 15, 2022. Public comments may also be submitted by email to or by mail to:

Karl Price, Senior Environmental Planner

Division of Environmental Planning

California Department of Transportation, District 7

100 South Main Street, MS 16A

Los Angeles, CA 90012


*All public comments must be received by January 16, 2023