San Mateo County's paving plans draw concern from cyclists

“This is an example of policymakers failing to consider the safety of cyclists,” Sandhya Laddha, policy director of the Silicon Valley Bicycle Coalition, said in an email. “Thousands of cyclists use the roads identified for chip sealing in the proposed project, and are in several locations — the primary user.”

Chip seal is a thin coating of liquefied asphalt covered in a layer of small rocks. It’s the cheapest resurfacing method available, less than half the cost of alternatives, per Caltrain, and often a go-to for low-traffic roads.

But it also takes time for rocks that don’t adhere to the sticky base coating to be swept from the road. The county in the past has placed “bicycles not advised” signs on roads where chip seal had been laid. The signs sometime remain for up to a year, according to John Langbein, a cyclist who rides the roads in question.

“They don’t provide an alternative route that is safe and pleasant to use,” he said, pointing to State Route 92 and 84, as well as Highway 1, heavily trafficked roads with no bike lanes and often nonexistent shoulders, the only other access to the coast.

Even upon fully curing, the rough surface is harsh for road cycling, sharp rocks can attach to tires and cause flats, and more damage is done in the event of a crash. Larger “chips” can also cause cracked windshields if flung from tires, Laddha added.

Among the roads to receive the treatment is Tunitas Creek Road, one of the most popular roads for cycling on the Peninsula. Old La Honda, Alpine and Lobitos Creek roads are also in the mix. Work is expected to begin Aug. 29 and wrap up by late September.

Laddha said the coalition advocates for slurry seal, another method of repairing aging roads that produces a smooth surface. The cost is $83,512 per lane per mile, compared to $47,765 for chip seal, according to Caltrans. She said there are other options as well, like cape seal or microsurfacing, which can be applied atop chip seal to reduce loose rocks and lessen the chance of accidents.

Those options, however, would more than double the project cost and elongate road closures, according to Krzysztof Lisaj, principal civil engineer with the county. He said while a project specific cost benefit analysis was not performed, chip seal is “the most cost-effective treatment on a per mile basis.”

To elevate cyclists’ concerns, the chip seal roads are swept multiple times after the seal is laid, including immediately after and 90 days after, he said. The county has been using chip seal on coastal roads since 2007, and has typically completed 25 miles per year.

He said roads that have been chip sealed “the bicycling community has been enjoying.”

“The county is committed to completing this project for the benefit of the homeowners, the drivers and the bicyclists, and that we appreciate their patience,” he said.

The county maintains 316 miles of roads in unincorporated areas, funded by gas tax revenue from the state. The 50 mile project is projected to cost $1.2 million, according to the county.

corey@smdailyjournal.com

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