Final cost estimates for the Devil's Slide tunnel and the Martini Creek Bypass will be released by "the end of this week," but are not expected to change much from figures released last week, according to a CalTrans official.
A complete copy of the tunnel study, which comprises 11 large volumes and is packed with dense technical data, will cost about $300, according to Dennis Bosler, project manager for the California Department of Transportation. Summaries of the two reports will be available to the public, but on Tuesday Bosler said complete data on the bypass cost estimate update may not be provided.
"How much it will incorporate (into the summary), I'm not sure," Bosler said.
Tunnel proponents said this week that they continue to fear that the bypass cost estimate is a low-ball figure that does not accurately represent its true construction costs.
"We have never anticipated that CalTrans would disclose complete and accurate information on the bypass," said tunnel advocate Kate Smit. "If we got complete information on the bypass, the bypass would be more than the tunnel."
One area of question is that CalTrans has only three sample soil borings along the bypass route. They date back to the mid-1960s. Bosler said at least 20 to 25 borings would be necessary for the bypass.
The borings determine the correlation between the desired stability of the bypass road and how steep hillside slopes, which the road will travel along, can remain. If poor rock quality is found, as was found in part of the proposed tunnel route, it could lead to increased costs for retaining walls, bolts or other stabilizing features.
Without precise information, as has been provided for the tunnel, Smit complained, "we're still not comparing apples to apples."
Bosler defended the cost estimate, saying that such possibilities were taken into consideration.
Meanwhile, CalTrans seems to have softened on the hard line previously taken that the current alignment of Highway 1 is unnaceptable for use as bicycle and pedestrian trail. He said CalTrans is not wed to a proposed $3.5 million repair of San Pedro Mountain Road for bikers and hikers, only that the agency does not want to be saddled with responsibility for the existing alignment if it is converted.
"If someone else wants to take over that road, that's fine," he said, adding that another possibility is to keep it on the current alignment, but move the portion of the road through the slide plane a little farther up the slope of the mountain so it is on more stable ground.
"If there's a better alternative (than San Pedro Mountain Road), we'd certainly be in favor of that," he added. "We just don't want the maintenance of the slide area."
There have been discussions of the roadway being taken over either by the county or Golden Gate National Recreation Area, but nothing has been proposed formally.