Wilson Signs Bill That May Block Linkup : Reseda Boulevard: Officials can impose restrictions if the road extension would harm Topanga State Park.

To the delight of environmentalists and state parks officials, Gov. Pete Wilson on Sunday signed into law a bill aimed at blocking construction of a four-lane extension of Reseda Boulevard through Topanga State Park.

“I’m delighted,” said Daniel Preece, who oversees the Santa Monica Mountains district for the state Department of Parks and Recreation. “We were very hopeful that he would sign it. . . . Certainly we think this bill will protect one of the finest state parks in California.”

The bill, introduced in July by Assemblyman Terry B. Friedman (D-Los Angeles), authorizes parks officials to impose restrictions on the planned 60-foot-wide thoroughfare if they determine that it will adversely affect Topanga State Park.

Parks officials have indicated that they will cut the width of the road to accommodate only emergency vehicles. They also intend to build a parking lot, restrooms and picnic areas where Reseda ends at the park, said Joseph T. Edmiston, executive director of the Santa Monica Mountains Conservancy.

The roadway was mandated by the city of Los Angeles more than a decade ago as part of an agreement allowing developers to build a luxury housing development near the park. The 178-house project, called Mulholland Park, was built in 1988 by Harlan Lee & Associates, but completion of the road was delayed by protests from homeowners and environmentalists.

Grading for the extension has already crossed a Santa Monica Mountains Conservancy tract next to the park but has stopped short of the park’s boundary. The rest of the extension would replace a narrow dirt fire trail, cut about 700 feet into the northern edge of the park and link up with Mulholland Drive.

Critics of the planned 8,500-foot extension said it was ordered at a time when officials envisioned more development for the mountains and is inappropriate now that much of the area has been set aside as parkland. Environmentalists and local homeowners also charged that a roadway would increase traffic, destabilize mountain slopes, create fire hazards, and promote housing and landfill development.

City fire and transportation officials advised completion of the Reseda-Mulholland linkup, saying it would afford easier egress in case of fire or other emergency and would alleviate traffic by siphoning off commuters headed for the San Diego Freeway.

But Edmiston said the issue “was not transportation, not fire access, but whether we’d put a major paved road through a wilderness state park. The governor came down four-square in favor of the state parks system, and that’s exactly where he should be from an environmental standpoint.”