The list of historic San Francisco infrastructure near-misses includes a freeway through the Panhandle, an airport on Treasure Island and a rotating restaurant atop what would become Sutro Tower.

But nothing would have changed the look of the city like the 1940s “twin Bay Bridge” plan, a proposal for a second identical span entering San Francisco. It was an oddity that the future would confirm made little sense; it would have added a new hellscape of cloverleafs and off-ramps into downtown San Francisco that would have accelerated surface-street gridlock.

And it was nearly built anyway — despite the vocal protest of The Chronicle, the mayor and more than 50 civic groups.

Talk of another bridge between San Francisco and the East Bay escalated quickly after the Nov. 12, 1936, completion of the Oakland-San Francisco Bay Bridge, which drew significantly more traffic than expected from the growing suburbs. The Bay Bridge’s chief engineer, Charles H. Purcell, had been appointed director of the California Department of Public Works, and saw efficiency in duplicating his own design.

The news dropped during a Feb. 16, 1947, surprise announcement by state officials, who left little room for input from San Francisco or other effected cities.

“Twin bridges are the State of California’s solution to the transbay traffic problem,” The Chronicle’s Floyd Healey reported, in a front page article. “At no point would the two bridges be more than 300 feet apart. That would be on Yerba Buena Island, where the new bridge would tunnel under the hill like the present one to leave naval installations undisturbed.”

A pingpong table-size model of the twin span showed a swarm of new off-ramps and raised roadways in San Francisco that only a fan of the Embarcadero Freeway could love. One double-decker roadway in the twin bridge plan appeared to go in a long and endless loop around Rincon Hill.

From the standpoint of publicity and as a tourist attraction, the “twin bridges would be one of the wonders of the world,” supporters argued in their presentation.

The Chronicle immediately protested the plan, supporting one of the more expensive southern crossings, including one between Hunters Point and Alameda proposed by military planners, that would have cars traveling in six lanes of underwater tubes. The newspaper published the rare front page editorial next to Healey’s more balanced story.

“Indeed, you might build, if the engineers are capable of it, a parallel bridge able to carry a million cars a day. But how would you get them onto and off the bridge?” The Chronicle argued. “We want another bay crossing, and fast — but we want it geared to the needs of tomorrow as well as today.”

From there San Francisco city leaders and The Chronicle waged a campaign against the “carbon copy” bridge, despite the fact that they had little power to stop it.

While the state gave the new bridge a “priority rating” in 1948 for quick construction, The Chronicle, argued, among other things, that plotting the bridges farther apart would make them less susceptible to annihilation from an atomic bomb attack.

San Francisco supervisors, including monorail advocate Marvin Lewis (Salesforce founder Marc Benioff’s grandfather), were aligned against the twin bridge and urged residents to write letters to state legislators. Then-San Francisco Mayor Elmer Robinson dedicated an entire 1949 fireside chat on KCBS to slamming the bridge.

“We would be better off without any additional crossing than to be confronted with a parallel or twin bridge,” Robinson told listeners.

In supporting the twin bridge plan, the state pointed to a study that said a southern crossing to Alameda would only divert between 5 and 20 % of Bay Bridge traffic. The state also already owned most of the land needed to build.

The Chronicle argued that future growth in San Mateo and Alameda counties would change traffic needs, and the future should involve moving traffic away from the center of San Francisco, not doubling down.

“This proposal is shortsighted, based on a false philosophy of growth and traffic of the bay region, disregards the once-burned-twice-shy experience, and … in 10 years (will) throw us all into the same traffic-choked tizzy we are in now,” the newspaper’s editorial board wrote.

State leaders seemed inflexible in those early years. The state’s chief engineer, Ralph A. Tudor, posed with a big smile in front of an expensive model of the twin bridge that was displayed at the Emporium department store, seemingly oblivious to the protests. But the state had obstacles of its own, including an inability to gain federal permission to build another tunnel on Yerba Buena.

The project continued to stall, state funds got tighter and the estimated costs rose. In 1951, the state unveiled a new refinancing plan for the original Bay Bridge that would include smaller projects (including the Webster Tube in Alameda) and an engineering study for a new southern crossing. That failed plan would have started where Broadway hit the Embarcadero shore, crisscrossed over Yerba Buena Island and ended in Alameda.

Ultimately none of these bridges were built. Energy in the 1950s and 1960s went into suburb-friendly projects, including an expansion of the freeway system and Marvin Lewis’ monorail proposal, which launched in 1972 as Bay Area Rapid Transit using some of the underwater tubes from the military’s plan.

As for another bridge? Proposals come up every few years for a southern crossing. But in 2019, the only place a parallel Bay Bridge belongs is in our nightmares. Presented as the future, it was just another close call, proposed by leaders who didn’t see where the Bay Area was going.

Peter Hartlaub is The San Francisco Chronicle’s pop culture critic. Email: phartlaub@sfchronicle.com Twitter: @PeterHartlaub