It was designed to speed motorists from Long Beach to Pasadena through the heart of Los Angeles County.
But for decades, transportation officials struggled to find a politically acceptable way to fill a 4.5-mile break in the 710 Freeway without paving over every home and business in between.
FOR THE RECORD: A previous version of this article said that the public comment period for the draft environmental impact report would start July 6. It began March 6 and ends July 6.
In 2013, officials narrowed options to five rail and roadway plans, the most ambitious of which would bore a $5.6-billion tunnel between Alhambra and South Pasadena.
But on Thursday, a community group submitted yet another set of ideas intended to turn the conversation away from tunnels and highways.
Beyond the 710, a coalition of community organizations, environmental attorneys and five San Gabriel Valley cities, said its plan would reset the debate over closing the gap between Interstate 10 and the nexus of the 210 and 134 freeways.
The group contends that simply expanding bus service, improving surface streets, adding bicycle routes and developing more walkable communities would better address traffic congestion, air pollution and the transportation needs of the west San Gabriel Valley.
"We are hoping to move beyond the old, tired 710 Freeway debate, which is wasting lots of time, money and resources," said South Pasadena City Councilwoman Marina Khubesrian, vice chair of the Beyond the 710 coalition. "Some of these ideas are new, but they have great potential."
The group presented its ideas to the board of the Los Angeles County Metropolitan Transportation Authority, which is evaluating options for the 710.
Metro board members listened to the proposals but did not discuss them. After the meeting, several declined to comment on whether they were swayed.
Options for the 710 extension are now in the environmental review process, which includes a public comment period that ends July 6. Under review are a bus system, a light-rail line, the tunnel and some upgrades to street intersections. The Metro board is scheduled next year to select one or more approaches or leave the route as it is.
Other groups in or near the freeway's path, such as the 710 Coalition, say they prefer putting the extension underground.
On Thursday, they said tunnel opponents are only hoping to undermine the review now underway. They say more than 300 community and advisory meetings have been held over the past four years to help form the current environmental impact report.
"To disrupt this process is unconscionable and disrespectful to the hundreds of residents that have participated in the process throughout the years," said Alhambra Vice Mayor Barbara Messina, whose city is a member of the 710 Coalition, along with four other San Gabriel Valley cities.
Noting that Alhambra is inundated with traffic coming off the 710, Messina said the options proposed by opponents would not do enough to increase mobility and reduce air pollution and congestion.
"This is all politics. We can thank Congressman Adam Schiff for this," Messina said.
Schiff (D-Burbank), who opposes the tunnel project, declined to respond to Messina's charge, but said some people "will have difficulty leaving the struggles of the past behind and embracing a new solution to our air and congestion problems that benefits all of the communities involved. What may have made sense 50 years ago, doesn't make sense now."
Appearing at a news conference at Metro headquarters in downtown Los Angeles, Schiff called on board members to think outside the box. He said he was willing to consider a tunnel but then saw the price tag balloon.
Instead of constructing the extension, Beyond the 710 envisions building several local surface-street projects, including a four-lane thoroughfare called Golden Eagle Boulevard that would head 1.9 miles north from the southern stub of the 710 to Fremont Street in Alhambra.
Golden Eagle would intersect Valley Boulevard, Alhambra Avenue and East Mission Road, allowing traffic to be distributed to other surface streets while protecting residential neighborhoods.
The group contends that the improvements would reduce congestion, especially around Cal State L.A., where a large number of car trips are made.
A proposal for the northern stub of the 710 in Pasadena calls for it to be filled in — an idea that could provide 35 acres of open space or developable land for homes and commercial buildings.
Another key proposal is a north-south transit corridor that meanders along the 710 route and would connect to major destinations as well as Metrolink service, the El Monte busway and the MTA's Gold, Green and Blue light-rail lines.
Khubesrian said the coalition also opposes an elevated light-rail option that is undergoing environmental review. She said it would not connect to the Gold Line or go to many popular destinations.
Coalition planners say the work that can be done immediately, such as street improvements, bikeways, safe pedestrian crossings and expanded bus service, would cost an estimated $875 million.
With additional funding, the group says that improvements to Metrolink, extensions of the Gold Line, rapid-transit bus lines and bike networks throughout the San Gabriel Valley could be done at a cost of almost $3 billion.
Supporters of the tunnel claim, however, that the draft environmental report illustrates the benefits of putting the freeway underground. Opponents, they add, are desperate to combat growing support for the project.
"This group is beyond reasonable," said Ron Miller, executive secretary of Los Angeles/Orange Counties Buildings & Construction Trades Council. "They are not new. In fact, they are the same vocal minority that continues to oppose the increasingly popular tunnel alternative."