All of the work on Diablo Road this year traces back to one land-use decision. In March 2020, Danville voters passed Measure Y. It permanently protected 381 acres of the Magee Preserve property as open space and allowed homes on 29 acres. The new signal at Blackhawk Road came out of that deal, and so did the new hillside trails south of the road. The Town of Danville is now building the last connecting piece, the paved trail behind the flaggers between Fairway Drive and Alameda Diablo.
Once that piece is done, Diablo's entrance becomes the meeting point of a continuous paved path and more than five miles of preserve trails. Separately, EBMUD has a pipeline replacement on its schedule for the streets inside Diablo itself.
Piece of work | Who is building or paying | Where it stands in November 2026 |
|---|---|---|
Diablo Road Multi-Use Trail, 0.9 miles | Town of Danville, built by Goodfellow Bros. | Paving, guardrails and handrails underway; completion expected December 2026 |
Signal at Mt. Diablo Scenic Blvd and Diablo/Blackhawk Rd | Davidon Homes, the Town and the County | Running since August 11, 2026 |
Magee Preserve trails | East Bay Regional Park District and Save Mount Diablo | More than 3.5 miles open since June 2025, plus two trails opened August 2026 |
Ranchitos del Sol Phase 2 pipeline | EBMUD | EBMUD's schedule calls for an October 2026 start and about 11 months of work |
The trail Danville first drew in 1989
The Town calls its segment the Diablo Road Pedestrian Trail and Drainage Improvements Project, CIP No. C-055. It first appeared in Danville's 1989 Townwide Trails Master Plan. The 2.1-mile route was meant to run on the south shoulder of Diablo Road between Green Valley Road and Blackhawk Road, and for decades the middle of it was never built. At the groundbreaking on October 30, 2025, Mayor Renee Morgan described how long it had taken, as quoted in the Town's groundbreaking announcement:
"Over 36 years ago, we were standing here, envisioning this trail."
The Town's segment links two pieces that already exist. On the west it runs from Fairway Drive and connects to the 0.5-mile Diablo Road Trail, also known as the Barbara Hale Trail. On the east it ends at a tank-access road about 1,200 feet west of the Mt. Diablo Scenic and Blackhawk intersection, where it meets a new 0.7-mile Class I path built as part of the Magee Preserve development. Danville's alignment summary places the eastern seam at the EBMUD access gate. From there the developer's segment runs about 3,750 feet east to Jillian Way. When it's finished, the whole route will be one 8-foot-wide paved multi-use trail. The Town describes it as expanding access to Mount Diablo State Park.
The budget is $5.2 million. Of that, $4.7 million comes from the Contra Costa Transportation Authority's Measure J transportation sales tax. In August 2025, the Town awarded the construction contract to Goodfellow Bros. California, LLC for $4,699,736.
Why it took most of 2026
Construction resumed on March 2, 2026, after a winter break. Tree removal came first, between Clydesdale Drive and Avenida Nueva. By June, the Town reported delays from two causes: compliance measures to protect nesting birds, and conflicts with existing utilities. A permit extension from the California Department of Fish and Wildlife let crews finish the remaining tree removal by June 1.
Over the summer, crews built the soldier pile retaining walls along Green Valley Creek. The Town called that phase the largest and most disruptive part of the project, and it required daytime traffic control between Fairway Drive and Alameda Diablo. The Town's October 15 update reported the walls and the creek work complete. Crews had moved to the strip between the creek and the road.
Here is what the remaining work means for anyone driving Diablo Road this month:
- Crews are installing drainage, preparing the trail foundation and paving the path.
- Guardrails along the roadway and handrails along the trail are still to go in.
- Lane closures are expected to continue "likely through November," weather permitting, in the same location.
- Closure hours are 8:30 a.m. to 5:00 p.m., with one alternating lane through the work zone.
- On some days no closure may be needed. Much of the remaining work involves large trucks and heavy equipment beside the road.
During the wall phase, the Town warned that traffic from Calle Arroyo would also be held as part of the flagging, and that school drop-off and pick-up times would see the longest waits. The Town's target for finishing the whole project remains December 2026.
The trails across the road opened first
The trail along Diablo Road was planned as the link between existing paths. The open space it borders opened in stages over the past year and a half.
On June 24, 2025, the East Bay Regional Park District held a ribbon-cutting that formalized public access to more than 3.5 miles of trails on the 381-acre Magee Preserve property. Those trails connect to the northern ridge of Sycamore Valley Open Space Regional Preserve. The Park District holds a recreational trail easement over the new trails. The Wiedemann Ranch Geologic Hazard Abatement District owns and maintains the land. Including the Magee Preserve connection, Sycamore Valley Open Space Regional Preserve now covers 695 acres across two ridges in Danville.
In late August 2026, Save Mount Diablo added more than two miles of trail with two named routes, as reported by Contra Costa News:
- The Art Bonwell Trail honors a Save Mount Diablo co-founder who was a cyclist. It runs parallel to the new Diablo Road bike trail and ties into it.
- The Do'-yum'-bel'-le Vista Trail carries the Bay Miwok name for Mount Diablo. Save Mount Diablo chose the name after talking with local tribes, and the trail has wide views of the mountain.
Davidon Homes donated the trail easement to Save Mount Diablo. Dave Hammond and the Trail Dogs volunteer crew worked on the build alongside the land trust's staff. Explaining the first name, Save Mount Diablo's Land Programs Director Sean Burke told Contra Costa News that a trail that "parallels and ties into the new Diablo Road bike trail" was "a no-brainer" for a cyclist co-founder.
Taken together, the open space came first and the paved spine is arriving last. When the Town's segment is finished, someone on the Barbara Hale Trail will be able to stay on paved path past the Diablo entrance and reach the Art Bonwell Trail's connection on the hillside.
The signal the new neighborhood paid for
The third piece has been working since summer. On Tuesday, August 11, 2026, Contra Costa County Public Works switched on a traffic signal at Mt. Diablo Scenic Boulevard and Diablo Road/Blackhawk Road, replacing the three-way stop. The project also added a dedicated right-turn lane for southbound Mt. Diablo Scenic Boulevard traffic turning onto westbound Diablo Road.
According to the County's announcement, Davidon Homes paid part of the cost as mitigation for its Magee Preserve development. The Town contributed traffic mitigation funds, and the County used gas-tax Local Road Funds. DeSilva Gates and MCH did the installation. That development is the one Measure Y allowed, 69 homes on 29 acres south of Blackhawk Road, planned "complete with bike paths and trails." The signal, the developer's 0.7 miles of path and the donated trail easement all came out of the same 2020 approval.
Inside the gates, the pipes are next
A separate project covers Diablo's own streets. EBMUD's project page gives October 2026 as the start of its Ranchitos del Sol Phase 2 Pipeline Replacement and puts the overall job at about 11 months. Final paving follows on each street. These are the streets on EBMUD's list:
- Avenida Nueva, El Centro and La Cadena
- Calle Los Callados, from Avenida Nueva to the dead end
- Ranchitos Del Sol
- El Nido, between Alameda Diablo and Casa Nuestra
- Club House Road and Calle Arroyo
EBMUD lists work hours of 7 a.m. to 4:30 p.m., Monday through Friday. Drivers entering or leaving a work area may wait up to 10 minutes. "NO PARKING" signs go up 48 to 72 hours before work starts on a street. Cars can stay on the street after hours and over weekends but must be moved before the next workday begins. Planned water shutoffs are announced with a door hanger. After a shutoff, EBMUD's guidance is to close toilet supply valves and run the front hose bib, bathtub or cold-water faucets for one to three minutes to clear air and loosened particles. Emergency vehicle access is maintained throughout. EBMUD held a virtual community meeting on September 29, 2026, and the recording is on the project page.
Calle Arroyo shows up in both projects. The Town's flaggers have been holding its traffic at Diablo Road, and EBMUD's pipeline list includes the street itself. On Calle Arroyo, the trail work and the pipe work may overlap this winter.
If you're thinking about what the finished trail, the new signal and next year's paving mean for a home near Diablo Road, The Mary Bonham Team follows these changes block by block from our Alamo office and is happy to talk through what they mean for your street. Let's Connect.
