In late September, a scathing staff report from the California Coastal Commission, which regulates development along the state's shoreline, disagreed with the TCA's contention that there are no feasible alternatives to the Foothill South.
The report cited Smart Mobility's work and recommended against supporting the toll road.
The transportation planning and engineering firm has done several reports for tollway opponents over the past two years.
The latest and most complete was released in September. Tollway opponents say the work has cost more than $100,000.
Smart Mobility researchers said the TCA's rejection of the I-5 option was based on conventional highway designs, such as partial cloverleafs, that can require large numbers of condemnations.
State-of-the-art improvements -- including streamlined interchanges -- would minimize condemnations, the report concluded.
In addition to the 7 miles of carpool lanes in San Clemente, the report overlooked two northbound lanes along the I-5 around Ortega Highway in San Juan Capistrano and a southbound auxiliary lane at Avenida Pico in San Clemente.
TCA officials said they were further concerned that Smart Mobility's highway layout would eliminate parking areas and lanes from major frontage roads, such as Rancho Viejo Road, Camino Capistrano, El Camino Real and Avenida de la Carlotta.
At Avenida de la Carlotta, two of the street's four lanes would be eliminated.
They also were concerned that the bridge and roadway at busy Crown Valley Parkway and I-5 would have to be raised substantially so a redesigned off-ramp could pass beneath.
"Their study is not worth the paper it's printed on," said Peter Herzog, a TCA board member. "The sad part is the Coastal Commission staff is taking it as gospel and putting it in their report."
Lucinda Gibson, a principal at Smart Mobility, said only 28 more condemnations resulted because the I-5 corridor is wide enough to handle the lanes the original study overlooked.
Gibson said that it is possible to raise Crown Valley Parkway, and that the traffic volume along the frontage roads, which she considers overbuilt, were low enough to justify using some of their right-of-way to widen the I-5.
Despite the study's errors, tollway opponents say the TCA could not escape the conclusion that it failed to consider highway designs for I-5 that can eliminate about $1 billion worth of property condemnations.
They cited a 2006 preliminary study by the city of San Clemente of proposed interchange improvements at Avenida Pico and I-5, which recommended three designs that minimized condemnations.
Toll road foes also point to TCA studies done in 2003 showing that improving I-5 would accommodate traffic growth as well as or better than the Foothill South.
Tollway officials ruled out the option during the review process because of high costs, the lack of state funds, and the large number of property condemnations.
"We expected the TCA to attack the study, but we feel the conclusions will hold," said James Birkelund, an attorney with the Natural Resources Defense Council, which has sued to stop the tollway.
"The TCA has failed to fully evaluate the alternatives like expanding I-5. There are clearly state-of-the art traffic designs that they didn't consider."
dan.weikel@latimes.com
