The Cambrian

What went wrong on Highway 1? Caltrans explains what happened and what's next

How did some 20 miles of Highway 1 north of Cambria get so rough?

Caltrans was trying to extend the pavement’s life by giving it a fresh top coat. According to Steve Price, deputy director of maintenance and operations for Caltrans District 5, the $2.1 million chip-seal coating applied last fall was designed to prevent future damage.

“We want to preserve the pavement we have,” he told San Luis Obispo Council of Governments members April 3, just as “you’ll want to paint your house before the siding rots.”

In last fall’s chip-sealing, the Caltrans contractor used larger aggregate rocks than had been applied previously on that roadway. They were selected for durability, he said. Since the “chips” degrade over time, larger ones could last longer.

Use of chip-sealing there also “was an economic decision,” Price explained, because full repaving would cost $7 million to $8 million.

As soon as the chip-sealing was complete, however, bicyclists and others began to complain that the surface was rough. Rocks kicked up by vehicles pelted cyclists and chipped vehicle paint and windshields.

Caltrans has swept loose rocks from the surface, rolled the pavement in a test area between Cambria and San Simeon and hired the U.C. Davis Pavement Research Center to come up with the best way to fix the problem. Results are due in May.

The agency expects the aggregate to smooth out over time as the rocks settle and wear down. Some say the pavement already is marginally less rough in the traffic lanes, because some rocks have been steadily re-pressed into the surface by the weight of passing delivery trucks, buses, motor homes, construction vehicles and daily vehicle traffic.

But self-smoothing takes time, and apparently no one knows how long it will take, especially in bike lane-road shoulder areas.

A bicycle and rider simply don’t weigh enough to force the aggregate further down into the emulsion. 

Despite pressure from the cyclists and SLOCOG to improve or resurface the road surface before the busy, economically vital tourist season begins — bringing with it many cyclists, motorists and ride events — Price said Caltrans won’t have recommendations from Davis until fall. And the agency won’t try permanent fixes until it knows the likely outcome of each recommendation, he said.

Of each suggestion, the agency has to ask, “Will it work? Will that be enough? Will it make it worse?” Price said. “My fear is spending a couple of million dollars out there and making it worse, or making no difference.”

Eventual results likely will alter chip-sealing policies statewide, he said.

Fixing the highway’s surface is “a statewide priority,” Price pledged. The agency is committed to doing that “if we can find a cost-effective strategy.”

He can’t authorize spending money for the redo, he said, because those decisions are made in the highest echelons of the department and state government. “But I’ve been reasonably assured that it will happen.”

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