The state Transportation Commission this week agreed to spend nearly $17.6 million this summer to repave about 33 miles of Highways 29 and 175 in Lake and Mendocino counties, most of which will go to fix last summer’s problem-plagued chip-seal work that cost $2.1 million.

In Mendocino County, Highway 175 will be repaved at a cost of $4.273 million from Highway 101 in Hopland to just east of the Mendocino-Lake County line.

In Lake County, Highway 175 will be repaved from 4.9 miles east of the Mendocino-Lake line to Highway 29 and from near Kelseyville to Middletown. Highway 29 will be repaved from south of Middletown to Hidden Valley Lake. Those stretches will cost $13.321 million to repave.

The Kelseyville-to-Middletown and Middletown-to-Hidden Valley Lake segments will smooth out stretches left rough by the last summer’s chip sealing. The chip sealing triggered an uproar in south Lake County, with more than 1,000 residents signing petitions demanding Caltrans fix the highways and local politicians joining the outcry as well.

The problem occurred when Caltrans, in a departure from its usual practice, used half-inch rock rather than the typical three-eighths-inch rock for the chip seal.

Caltrans won’t say outright that it made a mistake. But spokesman Phil Frisbie Jr. acknowledges that “it didn’t work out as we expected.”

He says there is a positive side to the chip-seal work despite its problems: The chip seal will provide better support for the new pavement, thus extending the life of the road.

Frisbie said he expects the paving projects to be completed by end of summer.