Leonis Adobe Imperiled, Suit Says : Preservation: An environmental impact report is being demanded for a proposed freeway interchange in Calabasas.

Attorneys for a cultural preservation association Monday filed a lawsuit against Caltrans and federal transportation agencies, charging that they illegally failed to prepare environmental impact reports for a planned $40-million Ventura Freeway interchange that could affect the historic Leonis Adobe in Calabasas.

Attorney Jack Rubens, who represents the nonprofit Leonis Adobe Assn., said Caltrans violated federal and state environmental quality requirements when it approved the project without preparing a report or even an environmental impact statement, which is less detailed.

The project would replace the heavily used Valley Circle Boulevard bridge over the Ventura Freeway with an interchange.

Also named in the suit, which was filed in U.S. District Court, were the U.S. Department of Transportation and the Federal Highway Administration, both of which are involved in the project.

Spokesmen for the agencies could not be reached for comment.

The suit, which seeks to overturn the Caltrans approval, also alleges that the agency neglected to show why there would not be a significant environmental impact on the 145-year-old Leonis Adobe.

“Caltrans took a calculated risk,” Rubens said. “They decided not to prepare an environmental impact report for a project that obviously needed one. They were just trying to save time and money at the expense of the community.”

The project centers on an unusual freeway “flyover bridge” that the state wants to build as part of the new interchange. The bridge would connect two-lane Calabasas Road on the south side of the freeway with four-lane Ventura Boulevard on the north in Woodland Hills.

Association officials have charged that the connection would turn Calabasas Road into an extension of busy Ventura Boulevard and ruin the quaint ambience of Old Town Calabasas--a two-block collection of clapboard storefronts that sprang up around the adobe about 75 years ago.

Rubens said the increase in traffic would ruin the area and negatively impact the Leonis Adobe, which is a museum and Los Angeles’ official Historic Cultural Monument No. 1.

He said the project is opposed by business groups and homeowner associations in the community.