While the debate over extending the 710 Freeway is six decades old, a new angle involving doing it by tunnel is grabbing most of the air time, even though four options are being examined by Caltrans.

For many, just picturing the longest freeway tunnel in California can be a difficult scenario. Extending the freeway 6.3 miles from the terminus at Valley Boulevard in Alhambra to the 210 Freeway in Pasadena, with at least 4.2 miles of the freeway completely underground with no exits, is definitely a new concept that politicians are trying to wrap their arms around.

During a spirited discussion at a forum Monday night at Cal State Los Angeles regarding the 710, panelists from four Southland cities answered questions from a political scientist about whether a 4-to-6 mile freeway tunnel under Alhambra, El Sereno, South Pasadena and Pasadena would be safe, practical and cost-effective.

“Tunnels have been around for hundreds of years in Europe,” answered Alhambra City Councilwoman Barbara Messina, who prefers the tunnel. “We went from downtown Paris to the Palace of Versailles in a tunnel. No problem.”

Those opposed to the extension left the audience of more than 200 people with scenarios of fire and death.

“I think it is very dangerous to be in a tunnel. I would instruct my family never to enter a five-mile tunnel, especially one being used for trucks. Imagine if you are in that. Imagine the smoke, the fumes, the fire,” said Glendale City Councilman Ara Najarian, who opposes the 710 extension.

“You can get killed crossing the street,” Messina shot back. “To say a tunnel is dangerous is really very, very lame.”

Michael Cacciotti, the council member from South Pasadena, which has successfully fought the surface route extension of the 710 for decades, said a tunnel is a risky, highly costly venture. A highway tunnel project in Boston, nicknamed the Big Dig, started out at $2.8 billion but finished at $15 billion, he said, while a tunnel freeway project in Seattle resulted in ground seepage and the tunneling machine getting stuck underground for years.

On March 6, a 26,625-page Draft Environmental Impact Report/Environmental Impact Statement on the 710 concluded that constructing a 6.3-mile freeway tunnel “would have the largest increase in freeway and arterial performance” of any alternative, but carries the highest price tag. At a price of $3.1 billion to $5.65 billion, the tunnel would cost more than a proposed light-rail line, estimated at $2.4 billion. Some argue the real cost will end up closer to $10 billion.

Four years ago, Caltrans and the Los Angeles Metropolitan Transportation Authority (Metro) began studying the environmental impacts of continuing the freeway underground instead of on the surface.

Besides the tunnel, the EIR examined four other options: traffic management solutions, a dedicated bus line, a light-rail train or no-build.

Najarian, also on the Metro board, opposes the tunnel. “The best choice involves a light rail. I don’t believe a tunnel will solve our problems,” he said.

A “single bore” double-decker tunnel, which would consist of two northbound lanes on top of two southbound lanes in a single tunnel, would have minor impacts to land, air, noise and aesthetics compared to the impacts from building a 7.5-mile light-rail train from East Los Angeles through Alhambra and Pasadena.

The study leaves it up to Caltrans and Metro to decide what to build. Also, if they choose the tunnel, the question remains whether it would take trucks and cars or prohibit truck traffic.

In a nuanced stand, Duarte City Councilman John Fasana, one of the panelists and a Metro board member, said trucks should be prohibited from the tunnel. He would prefer to divert truck traffic up the 5 Freeway or along the 60 Freeway east. He and others said the 710 tunnel would not be suitable for trucks, in part because they would have to travel up-grade going northbound.

Najarian agreed, but said the trucking lobby and port shipping businesses will want access to the new portion of the freeway to move goods from south to north. “It is Metro’s intention that this be a truck-freight corridor,” he said.

Since the tunnel is expensive, Metro and Caltrans will need to bring in private companies to build it. That means the tunnel will be a toll road. Najarian said estimates of the toll could be as high as $14 one way, a fee shipping companies can absorb into the cost of doing business.

“Truckers will be willing to pay it. Your average soccer mom isn’t going to pay that,” he said.

Messina said Caltrans and the Southern California Association of Governments have already heard from private road builders who would put up capital. Fasana said a public-private partnership is much harder to do for rail lines.

He also said tunnels already exist beneath Hollywood and downtown Los Angeles, but for subways not vehicle traffic. So far, they haven’t been a problem.

“Where that gap is, the tunnel is the option we should look at seriously,” Fasana said. “But we will need to see whether the public-private partnerships materialize.”

Comments on the EIR/EIS are being accepted by Caltrans and Metro through July 6. Send written comments to: Garrett Damrath, chief environmental planner, Division of Environmental Planning, California Department of Transportation, District 7, 100 S. Main St, MS-16A, Los Angeles, CA 90012. Submit comments online at: http://www.dot.ca.gov/dist07/resources/envdocs/docs/710study/draft_eir-eis/comments.php.