Replacement of the Highway 12 bridge spanning the Laguna de Santa Rosa at Sebastopol's eastern gateway is likely to present motorists with additional delays at an already tight bottleneck as construction gets underway this summer, officials said.
A Caltrans spokesman said every effort would be made to keep traffic moving smoothly when work begins June 15 on a new span for the busy east-west corridor.
But there will be times when only one lane of traffic is open — hopefully only at night, to reduce the impact on motorists, spokesman Allyn Amsk said.
Caltrans officials are hosting a public meeting on the two-year project in Sebastopol on Monday night.
City officials and some business owners said additional congestion is unavoidable during construction, given the traffic backups that already occur in the area.
The stretch of road carries an average of 23,200 vehicles daily, Caltrans officials said, citing 2012 data.
"It's just a daily traffic jam," said Juan Moya, who manages a Chevron service station on Highway 12 east of the bridge and often sees cars backed up in his direction.
The 220-foot span, first built in 1921, is being replaced because of structural deficiencies, including underwater scouring and erosion in the foundation, first discovered during a 2002 inspection, Caltrans said.
The $9 million replacement work will result in a wider bridge, with 8-foot shoulders and sidewalks at least 5 feet wide in each direction, improving pedestrian and bicycle access and safety along the roadway.
"I think it's going to be better for everybody overall, in the long run," said Darius Azarvand, whose family owns Sebastopol Liquor and Deli on Highway 12. "But it's going to hurt some of the smaller businesses in the short term, of course."