The prospect of 16 miles of asphalt ending near Trestles, the "Yosemite of Surfing," has galvanized surfers and environmentalists.
They argue that the project would wipe out endangered species, ruin one of the state's most beloved parks and block the sediment deposits that create the world-class waves.
Proponents, including weary commuters, say the $875 million project will end crushing gridlock on Interstate 5 between Orange County and San Diego, where more than 125,000 cars pass each day.
Studies commissioned by the Transportation Corridor Agencies, which finances and builds Orange County's toll roads, estimate that by 2025, a 16-mile drive on the freeway will take an hour.
Last month, Gov. Arnold Schwarzenegger and state Treasurer Bill Lockyer weighed in, with the governor in favor of the road and Lockyer opposed.
Yet those on both sides see something more than a battle over a few lanes of pavement in the spiraling debate, which has attracted more than 500 video postings on YouTube and dozens of pro- and anti-toll road Web sites, protests, statehouse rallies and blogs.
"We in California are confronting a very important moment and that is, 'How do we solve our infrastructure needs?'" said Elizabeth Goldstein, president of the California State Parks Foundation. "Are we just going to elbow parks out of the way or are we going to treat them as the treasured resources they are?"
The California Coastal Commission votes today on whether the proposal meets Federal Coastal Management Act standards -- a requirement for it to move forward.
The commission is expecting so many people that it moved the meeting to a 3,000-seat fairgrounds in San Diego.
A staff report prepared for the commissioners last year said that "it would be difficult to imagine a more environmentally damaging ... location" for the road.
The Transportation Corridor Agencies, which finances and builds Orange County's toll roads, published a rebuttal report and offered a $100 million contribution to the state parks system as part of the deal.
"We have to base our decisions on sound science and the other side bases theirs on emotion," said Lance MacLean, chairman of the Foothill Eastern Transportation Corridor Agency. "They're not having to prove their point ... and it's kind of hard to fight that."
Environmentalists say the toll road will destroy habitat for nearly a half-dozen threatened or endangered species, including the Pacific pocket mouse and the arroyo toad.
They also say it will cut 161 camp sites and create a concrete eyesore in the middle of the 2,100-acre San Onofre State Beach, which stretches from the coastal bluffs to the dry interior canyons. San Onofre is the state's fifth-most popular park and attracts 21/2 million visitors a year.
Surfers worry the road will block sandy runoff from the San Mateo Creek watershed. They believe this sediment builds up underwater and creates the wave breaks that earn Trestles one of 12 coveted spots on the surfing World Championship Tour.
Transportation officials, however, counter that the road's alignment was tweaked to avoid sensitive habitat and will not affect Trestles.
The group hired independent scientists, who concluded that sediment deposits offshore would remain unchanged, said MacLean, who is also a Mission Viejo city councilman.
"We've done the science behind this," he said. "The last thing I want on my tombstone when I die is, 'This is the guy who built the project that destroyed Trestles.'"
MacLean said the alternative -- a widening of Interstate 5 -- would mean the destruction of more than 1,200 homes and businesses in a booming area set to add 14,000 new homes in the next 25 years.
"There's a human factor here that you have to take into account," MacLean said. "Who's protecting the residents and the businesses and the citizens, instead of the pocket mouse?"