September Construction Updates

Construction on the Diablo Road Multi-Use Trail throughout September will be focused on finishing activities along Green Valley Creek, including completion of the retaining walls that will provide the foundation for a portion of the new multi-use trail and help provide increased stability for the roadway. Upon completion of all the retaining walls in the creek area, grading work to prepare a solid subgrade for the trail’s pavement structural section will take place. Work in September will also include the addition of underground drainage systems and more retaining walls to provide increased stability in the hillside portion of the trail segment.

We’ll be updating this page weekly throughout September with the latest construction progress and a look at what’s coming next, so check back for updates.

The new multi-use trail is at the heart of this project, but its construction also brings important infrastructure improvements to Diablo Road. The new retaining walls will strengthen and stabilize the roadway along Green Valley Creek, significantly reducing the potential for erosion in this area and the need for future road closures.

We recognize traffic impacts have been a challenge during this work. Danville staff has been in close coordination with the construction team to adjust flagging operations and we have pushed back the start time from 7:00 a.m. to 8:30 a.m. (as of August 31) to help with the flow of traffic, especially during school drop off hours. The earlier start time from August 11 – August 28 allowed crews to get make major progress on installing piles and concrete work for the retaining walls.

Project update – Friday, September 4, 2026

As of Friday, September 4, crews have installed 70 of 72 piles. What are piles? They are the beams set vertically in concrete that hold the concrete panels of the retaining wall in place. They’re installed 30-40 feet into the ground to provide stability for the retaining wall and roadside.

Crews are also working on placing the concrete panels for the retaining walls. There are 3 sections of retaining wall that total 410 linear feet. As of Friday, September 4, approximately 245 feet of wall have been installed.

Coming up next week: During the week of September 7-11, crews will finish installation of the remaining piles and most of the remaining sections of concrete panels in the retaining walls. The goal is to have all wet concrete work on the retaining wall completed by September 15.

Project update – Friday, September 11, 2026

As of Friday, September 11, crews have installed all 72 piles for the retaining walls, and beam placement for all three wall sections is now complete.

Crews have also continued installing the concrete panels between the beams. Approximately 320 feet of the 410 feet of retaining wall is now in place.

Coming up next week: Crews will continue installing the remaining concrete panels and begin drainage and backfill work behind completed sections of the retaining walls. Concrete work will also begin between the retaining walls and the roadway to stabilize the ground where the new path will be constructed.