In 1956, Elvis Presley was hip-shimmying his way into American hearts, the minimum wage went up to $1 per hour, and a trip back and forth across the newly built Lake Pontchartrain Causeway cost $2.

Nearly six decades later, Miley Cyrus has made twerking part of the nation’s lexicon and minimum wage is up to $7.25 per hour. But a trip back and forth across the nearly 24-mile-long Causeway is still just $2 with a toll tag. A cash trip costs a dollar more, the result of the Causeway’s lone toll increase, some 19 years ago.

But now, the bridge’s managers are floating the idea of raising the toll, this time to pay for safety improvements aimed at preventing “overboards,” or accidents in which a vehicle goes off the bridge into the waters of Lake Pontchartrain. Those accidents nearly always result in fatalities and long delays, both when the accident occurs and again when the submerged vehicle is recovered.

In the latest incident, a GMC Sierra pickup went over the rail on the southbound span as if it were “a ‘Dukes of Hazzard’ ramp,” driver Andy Pate said. Luckily, a passing motorist saw what happened and jumped into the lake to help a dazed Pate, who had managed to get out of his truck.

Others haven’t been so lucky. Last fall, the body of 19-year-old Miguel Rodriguez was found a day after his Ford F-250 pickup went over the side. Rodriguez initially surfaced and said he was fine but then slipped back beneath the waves.

Causeway officials worry that these accidents are becoming more frequent. There have been four in the past two years and 12 since 1994, all of them on the bridge’s older, southbound side. Nine of the 12 have resulted in fatalities, according to numbers provided by Carlton Dufrechou, general manager of the Greater New Orleans Expressway Commission, the body that operates the Causeway and the Huey P. Long Bridge.

The Causeway remains the engineering marvel it was when it opened in the 1950s as the longest bridge in the world, but it has struggled to keep up with the changes around it, Dufrechou said. The structure is solid, but cars have evolved since the 1950s. Half of the Causeway traffic is by pickups and SUVs, vehicles with high clearance and a high center of gravity, Dufrechou said.

The southbound span has a concrete rail that is just 25 inches high and not very difficult for large vehicles to hurdle. The steel rail mounted on top of the concrete was intended as a handrail for motorists who had been forced out of their cars; it does nothing to stop cars from going over, Dufrechou said. On the northbound side, where no cars have gone into the lake in the past several years, the concrete rail is 31 inches high.

To address the problem, the Causeway Commission paid for an analysis from the traffic study group at Texas A&M University.

The group presented three options for reinforced rails, and last month, it tested prototypes of each option on an unused turnaround at the 9-mile mark. Each of the three is a metal rail that could be mounted on top of the existing concrete and that, according to test results, would be able to withstand the impact of a large panel truck, like a big U-Haul.

The three options are to be crash-tested at an airfield near Texas A&M before a final recommendation is made near the end of the year.

Putting the enhanced rails on both sides of the bridge would cost an estimated $50 million, Dufrechou said.

Another proposed safety feature — 12 safety bays, placed at intermittent spots along the bridge’s two spans — would cost another $60 million. Though the bays — 672-foot-long stopping areas placed on the right side of the two spans like a short shoulder — wouldn’t necessarily stop cars from going over the edge, they would provide some extra room for the handful of breakdowns that happen on the Causeway every day. Along with the enhanced rails, the bays are on Causeway officials’ wish list of safety improvements.

More ambitious projects, like adding a third lane to the bridge, would be cost-prohibitive, Dufrechou said.

The Causeway has two major sources of income: tolls and money from a state highway fund. The latter provides about $4.5 million per year to service the Causeway’s $46 million indebtedness. The approximately $16 million from tolls covers the commission’s operating expenses. Any excess goes back into bridge upkeep and maintenance projects, Dufrechou said.

So the commission must find some new funds if it wants to add the proposed safety features. Federal and state grants are a possibility, but competition for those dollars is fierce. Raising tolls would be a guaranteed income source for a bridge that gets 12 million trips a year.

“To save lives, we must upgrade,” Dufrechou said.

It will be up to the commission to decide whether to raise the tolls, but Dufrechou said the body will not consider a hike without collecting public input first. If a recent public meeting in Mandeville is any indication, the idea could be controversial.

“I am totally against a raise in tolls,” Mandeville resident Mitchell Christen said. He said officials should concentrate on enforcing traffic laws on the bridge, writing tickets to enhance safety and generate cash.

“There’s no tailgating enforcement, and social media is putting people’s lives in danger,” he said, referring to reports that some accidents have been caused by drivers checking their phones.

Christen also cited speeding as a problem, a concern that Dale Provenzano, of Mandeville, seconded.

“Every day on that bridge, I fear for my life,” he said. Raising the rails to keep out-of-control cars on the bridge — as the proposed railings are designed to do — would only make wrecks worse, he added.

“Instead of a one-car accident, you are going to have an eight-car accident,” he said.

Another commuter, Jason Cottone, asked whether fines collected from tickets issued by the Causeway Police — which go to Jefferson and St. Tammany parishes — could instead be diverted to pay for improvements to the bridge.

But feedback on the proposal wasn’t all negative.

Dean Duplantier said he has been a commuter across the bridge since 1981, and he accepts the idea that he might have to pay more to use it.

“I think it’s inevitable that the tolls are adjusted,” he said.

Don Shea, St. Tammany Parish’s director of economic development, noted there has been only one toll increase since the Eisenhower administration. Shea, who said he was speaking as a private citizen and not in his official capacity, said he believes now is the time for a second increase.

Causeway officials were adamant at that meeting and in interviews that there is no specific plan to raise the tolls. They are waiting to hear a recommendation from the Texas A&M team before looking closely at how much new rails would cost and how much money a toll increase would raise.

Such a plan could be formed in the early part of 2015, commission Chairman Michael Lorino said.

“At the end of the year, we will know, approximately, if it works or not. We are going to know approximately how much it’s going to cost,” he said of the improved rails. “Then we will be able to sit down and evaluate whether to raise the tolls.”

Lorino said he sometimes pays almost $1 per mile on other toll bridges. The Causeway, on the other hand, costs $2 or $3 for 24 miles, and it’s free going north, he said.

He also said the commission would study several options, such as higher tolls for pickups and SUVs only.

Any deliberations over the tolls will be open to the public.

Lorino said he would likely support a toll increase.

In Dufrechou’s view, the bridge just needs to keep up with the times.

“The problem is that we have two 20th-century bridges that are now operating in a 21st-century environment,” he said.

Follow Faimon A. Roberts III on Twitter, @faimon.