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Arnold roundabout set for bid

The proposed – and sometimes reviled – Arnold Drive roundabout at Agua Caliente Road is on schedule and could go out for bids around the first of the year.

  Last Tuesday, Sept. 11, the Sonoma County Board of Supervisors adopted a resolution for a mitigated negative declaration approving environmental documents and the $2.1 million project.

  Tom O’Kane, the county’s deputy director of Transportation and Public Works, said he expects to put the project out to bid around the first of the year, and that bids are usually advertised for about 90 days. That would mean, depending on weather, construction could start on the project in April or May of 2013.

  This project is being funded from a combination of Proposition 1B, Measure M and Sonoma Valley Traffic Mitigation funds. Proposition 1B was a transportation bond approved by voters statewide in 2006, while Measure M was a quarter-cent sales tax approved by county voters in 2004.

  The roundabout would replace a four-way stop.

  The property on the west side of the proposed roundabout belongs to Hanna Boys Center, which will realign its driveway to Agua Caliente Road as part of its $15 million capital improvement project.

  According to the resolution, the roundabout is designed to accommodate truck-turning movements by including rounded, or “traversable” curbs on the edge of the center island and truck apron. Native vegetation would be included in the center island, roadside trees would be retained where feasible and trees to be removed will be replaced with native oak trees and shrubs within the public right-of-way where space allows.

  The existing road shoulder of Arnold Drive and Agua Caliente Road will connect to the roundabout with a new 10-foot-wide, paved bike/pedestrian pathway. The new bike/pedestrian pathway is separated from the vehicular travel lanes that form the roundabout with 6-inch high curbs.

  The area between the curb and path will be surfaced with cobblestone or stamped concrete, offering a visual, textural separation for bikes or pedestrians. These rough surface textures are purposely designed to alert pedestrians and cyclists of adjacent vehicular travel lanes.

  Within the project limits, but beyond the shared sidewalk and bike path, Class II bike lanes will be constructed consistent with the Bikeways Plan. Splitter islands (separators) proposed in the middle of each vehicle travel lane would also be textured and include 6-inch-high curbs. These areas will not only separate the travel direction of vehicles, but also offer “refuges” for pedestrians crossing the roads, so that they only have to cross one direction of travel at a time.

  When the matter was being considered by the Sonoma Valley Citizens Advisory Commission in July 2011, a number of audience members opposed the project citing possible safety issues, concerns about truck traffic and the spoiling of a rural road with what was termed an “urban solution.” But the project also had its supporters including one who wanted another roundabout “down at Bonneau’s.”