The Hardest Stretch of Danville's Diablo Road Trail Comes Last, and Paving Is Up Next

Why are the trails at the far end of the Diablo Road route already open while the middle stretch is still behind traffic cones? Green Valley Creek runs along that middle stretch, and building a trail beside it has taken the longest.

If you've sat in the alternating one-way traffic on Diablo Road this fall, you've been waiting on the toughest 0.9 miles in a route the Town first sketched in its 1989 Trails Master Plan. Crews have been building retaining walls into the steep slope between Green Valley Creek and the roadway. The Town's latest update says the walls and the in-creek work are finished, and the job has moved on to drainage, the trail foundation and paving. Danville San Ramon reported on October 20 that paving was planned for November and that the project was set to finish in December.

Most of the trails on the eastern end are already open. This last link is what joins them to the trail Danville has had for years.

The Town's Share Was the Hard Share

The full route is a 2.1-mile, 8-foot-wide paved Class I path. It links the Green Valley Road corridor with the Blackhawk Road corridor. The work was split by who builds what. The eastern portion falls to the developer of Magee Preserve, and the Town takes the western portion. The Town's project page describes the eastern ground as relatively flat. The western ground has creek crossings, steep slopes, and the question of where trail users should cross Diablo Road.

That crossing matters because of a basic layout fact. The existing Barbara Hale Trail runs along the north side of Diablo Road, west to Green Valley Road. The new segment runs along the south side. The two sides meet at Fairway Drive, where the project adds a pedestrian-activated HAWK signal. It stops cars when someone on foot or on a bike needs to cross. The Town awarded the signal contract in July, and design submittals were underway as of the September construction update. Without that signal, the new trail and the old one would sit on opposite sides of a busy road.

Money took time as well. When Magee Preserve was approved, the Town had roughly half the funding it needed. By summer 2021 it had secured the rest. The Town's October 2025 groundbreaking notice set the budget at $5.2 million, and $4.7 million of that comes from Contra Costa Transportation Authority Measure J sales-tax funds. That means roughly nine of every ten dollars in the budget come from the countywide transportation measure.

What Went Into the Creek Bank

The trail surface is the simplest part of this job. Most of the time and cost went into what holds it up. As of the Town's September update, three soldier-pile walls and a mechanically stabilized earth block wall were substantially complete beside Green Valley Creek. Some of the steel piles go about 28 feet into the ground. They support the trail above the creek and help protect Diablo Road from erosion.

Wildlife-agency deadlines set the pace for the creek work. According to Open Governance, concrete work in the creek had to be done before a September 15 wildlife-agency deadline, and the contractor was racing an October 15 cutoff for permitted creek work. The Town's October 15 update says the major walls and the creek work are complete. So the riskiest deadline on the job has passed. What's left happens on dry ground between the creek and the road.

The project also covers drainage improvements, grading, tree replacement, and fencing to keep out both wildlife and cattle. The Town Council awarded the construction contract on August 12, 2025, for $4,699,736 plus a $469,974 contingency.

Three Segments, One Route

When the Town's piece opens, the route will have three parts built by three different parties over very different stretches of time.

The new segment ends near the Mt. Diablo Scenic Boulevard and Blackhawk Road junction. That puts it at the gateway to the state park's south approach, which runs from Diablo Road up Mt. Diablo Scenic Boulevard. The trail ends at that gateway area and doesn't run up into the park. Open Governance described the long-term goal as a connection that brings the Mount Diablo foothills much closer to being an everyday walking and biking route from downtown neighborhoods.

The Eastern End Opened First

This is why the order of construction matters. The far end of the route already has trails you can walk.

Danville voters approved Measure Y in 2020. It protected 93 percent of the 410-acre Magee property. The preserve now includes 381 acres of publicly accessible open space, and 69 homes were planned on 29 acres south of Blackhawk Road. More than 3.5 miles of East Bay Regional Park District trails there have been open since June 2025. Those trails connect to Sycamore Valley Open Space Regional Preserve.

In August 2026, Save Mount Diablo announced two more trails, which together add over two miles. The Do'-yum'-bel'-le Vista Trail takes its name from the Bay Miwok name for Mount Diablo and was chosen after talks with local tribes. The Art Bonwell Trail honors one of the land trust's co-founders. Volunteers built them alongside Save Mount Diablo staff, including Dave Hammond and the Trail Dogs and students from Athenian High School.

The Art Bonwell Trail is the one that ties the preserve to Diablo Road. Sean Burke, Save Mount Diablo's Land Programs Director, told the land trust that naming it for Bonwell, a cyclist, was "a no-brainer" because the trail "parallels and ties into the new Diablo Road bike trail."

Until the Town's 0.9 miles and the Fairway Drive crossing are both finished, the Barbara Hale Trail and the Magee Preserve trails remain separate networks.

Between Now and Opening Day

The Town and its development services staff have listed what's left. In rough order:

1. Finish the trail base and paving between the creek and Diablo Road. Drainage repairs wrapped up earlier in October.
2. Install handrails at each of the large retaining wall systems.
3. Place a steel-backed timber guardrail along the roadway next to the creek.
4. Add stormwater landscaping and signs.
5. Bring the HAWK signal at Fairway Drive online. No activation date has been published.

The Town's August advisory expected the project to be fully complete by December 2026. The October 15 update says the work is on schedule. Open Governance noted that the schedule will depend on construction conditions and weather. Treat December as a target until the Town announces an opening.

For drivers, the Town expects lane closures on Diablo Road to continue likely through November, weather permitting. They'll stay in the same location and keep the same 8:30 a.m. to 5 p.m. hours. The closures run as alternating one-way traffic between Fairway Drive and Alameda Diablo, with traffic control at Calle Arroyo as well. The 8:30 start time is a change. The Town moved it from 8 a.m. and shortened the affected section to ease morning congestion. Some days won't need a closure. Much of the remaining work involves large trucks and heavy equipment on the roadway, though, so the Town is asking for patience through the final weeks.

The same corridor is getting more upgrades. The Contra Costa Transportation Authority's Smart Signals Program, which the authority expected to award in November, includes new traffic-signal detection cameras at intersections on Diablo Road, Danville Boulevard and San Ramon Valley Boulevard.

A new trail at the end of your street can change how buyers picture life on your block. If you live along Diablo Road or near Magee Preserve and are wondering how this connection affects your home's value, The Duarte Team can go over it with you, using recent local sales. Request a Free Home Valuation, and we'll put together a clear, neighborly picture of where your home stands.