San Francisco: 130,000 Trip Hazards Repaired Under StreetTreeSF

• Client: San Francisco Public Works, Bureau of Urban Forestry

• Program: StreetTreeSF

• Scope: Survey and repair of tree-related and other sidewalk trip hazards by horizontal cutting, in the same field visit

• Years: 2016 to present, 10+ years; current five-year contract runs through June 2028

• Hazards repaired: 130,000+

• Sidewalk surveyed and repaired: 200+ miles, about 20 miles a year on average

• Repairs per year: 25,000 to 30,000

• Detection threshold: 1/4 inch and up

The challenge

San Francisco's street trees lift sidewalk panels, and the city's hills mean many of those panels sit on steep grades. A conventional fix, removing the panel and often cutting roots to repour it, costs the city a tree it has spent decades growing and closes the walkway for the cure period. The Bureau of Urban Forestry needed a way to keep the trees, keep the sidewalks open, catch hazards early before they got worse, and hold a record that supports the city's accessibility obligations.

What PCC did

• Survey and repair in the same visit. Hazards at 1/4 inch and up are identified, measured, photographed and GPS-located, then cut in the same field visit, so they are corrected immediately rather than queued.

• Cut from the top. Root-heaved panels are corrected in place by cutting the raised edge to a 1:12 slope, the same slope standard the ADA sets for ramps. No excavation, no root severing, no panel removal. The mature street tree is preserved.

• Any grade. The equipment works on all street grades. Cross-slope is restored to PROWAG spec on every repair, which preserves the established drainage flow down the hill.

• Priority where it matters. Repairs are prioritized near schools, hospitals, senior centers and transit stops.

• Data the city budgets from. All work is GPS-tracked and photo-documented for the city's ADA compliance record, and city managers use the data to build their overall sidewalk management budgets.

Results

• 130,000+ trip hazards repaired since 2016.

• 200+ miles of sidewalk surveyed and repaired, about 20 miles a year.

• 25,000 to 30,000 repairs completed each year.

• A five-year contract re-awarded under competitive procurement, currently running through June 2028.

• Street trees kept in place on every root-related hazard within cutting range.

What it means for other cities

San Francisco is the proof that cutting scales: tens of thousands of hazards a year, on the steepest terrain in any PCC program, without removing trees or panels. For a city with a street tree program or a backlog of root-heaved sidewalks, three points carry over:

1. The tree and the sidewalk are not a trade-off. Cutting from the top removes the hazard and leaves the roots alone. Only panels beyond cutting range go on the replacement list.

2. Same-visit repair closes the gap between finding and fixing. A hazard cut the day it is surveyed is not sitting in a claims window for a season.

3. The data is the budget tool. Because every repair is GPS-located and photographed, the city can see where hazards recur and what next year's work should be.

See Seattle for a grid-based program on a flatter network, or how a municipal program works year to year.

Frequently asked questions

Who repairs sidewalk trip hazards for San Francisco Public Works?

Precision Concrete Cutting has worked for San Francisco Public Works, Bureau of Urban Forestry, since 2016 as part of the StreetTreeSF program. More than 130,000 trip hazards have been repaired across more than 200 miles of sidewalk. The current five-year contract runs through June 2028.

How does PCC fix a sidewalk lifted by a street tree without removing the tree?

The raised panel is cut from the top to a 1:12 slope. No excavation, no root severing, no panel removal, so the tree, the panel and the walkway all stay.

How many repairs does San Francisco complete each year?

Between 25,000 and 30,000 a year, about 20 miles of sidewalk a year on average, at a detection threshold of 1/4 inch and up.

Does the cutting method work on San Francisco's hills?

Yes. The equipment works on all street grades, and cross-slope is restored to PROWAG spec on every repair, which preserves the established drainage flow.