Study: Tollway route violates state Coastal Act - Commission's staff urges rejection of proposed road through San Onofre State Beach.

The 236-page analysis conflicts with claims by the Transportation Corridor Agencies that the proposed route for the Foothill South tollway is the least harmful to the popular coastal park out of eight alternatives considered by the Irvine-based agency.

Estimated to cost $875 million, the 16-mile tollway is billed as the final link in Orange County's network of toll roads, allowing drivers to bypass clogged Interstate 5 in the southern part of the county. It would begin at Oso Parkway in Rancho Santa Margarita, pass through the state park north of the beach and connect with I-5 at Basilone Road south of San Clemente.

"It's difficult to imagine a more environmentally damaging alternative location," the commission's staff concluded. "No measures exist that would enable the proposed alignment to be found consistent with the California Coastal Act."

Passed by voters in 1972 and made permanent by the Legislature in 1976, the act is designed to regulate development along the state's 1,100-mile shoreline.

The report is a blow to proponents of the tollway project, which has mushroomed into a statewide conflict over where to draw the line between protecting the environment and building highways to ease traffic congestion.

The new findings set the stage for a major clash at the commission's Oct. 11 meeting. Hundreds of opponents and supporters of the proposal are expected to turn out at the public hearing in San Pedro.

The staff report recommends that commissioners deny certifying the Foothill South project as being consistent with the coastal act. Certification is required to secure state and federal development permits.

If commissioners accept the staff recommendation, the tollway agency can appeal to the U.S. Department of Commerce because the park sits on land leased at the Camp Pendleton Marine Corps base.

Tollway officials disagreed with the commission report, saying there were errors and inconsistencies with the assessment. They declined to elaborate.