Hy-Vee’s top executive, Randy Edeker, walked into a Miami hotel five years ago and saw an innovation that he thought would work in the grocery chain — public restrooms for one.

With every large format store it has opened since 2012, including three in the Twin Cities in the past year, Hy-Vee built at least nine individual restrooms, ­joining the ­vanguard of a design movement that had momentum even before transgender bathrooms became a political controversy this year. Big, multi-stall bathrooms as we know them — often dirty and uncomfortable for many people — are on borrowed time.

“Pick a door, any door,” shopper Samantha Chavez said outside the bathrooms at the Oakdale Hy-Vee on a recent visit. “I can handle all my kids in the bathroom with me and it’s private.”

Single-user restrooms reduce waiting times, relieve social pressure that people with shy bladders feel in public restrooms, solve the problem faced by parents and opposite-sex caregivers waiting for their charges, and eliminate the controversy over where a transgender person should go.

Roxanne Anderson, co-owner of the Cafe SouthSide in Minneapolis and a transgender person, said single-user bathrooms please most people. “I’ve talked to a man who was in charge of his mom’s care after she broke her hip and moms with young sons who feel reluctant about sending them into the men’s bathroom,” she said. “Multi-user bathrooms can make it difficult for people of all kinds.”

Restaurants and hotels led the trend, sometimes in response to cost and space issues but also because of the competitive pressure to create distinctive services.

More businesses and public institutions are catching on. Two of Minnesota’s biggest operators of public restrooms, the University of Minnesota and Minneapolis-St. Paul International Airport, are remaking them to offer more comfort and privacy when nature calls.

The university is changing signs and adding locks on about 450 existing single-user restrooms, which were previously designated by sex, to make them available for anyone. “By the time we’re done, about 25 percent of the ­campus restrooms will be gender-neutral,” says Dave Hutton, a senior director in facilities management at the U. “The general trend is to include more single-user restrooms for future construction and major renovation, too.”

The airport, which started overhauling restrooms in 2012, plans to spend $12 million in the next three years on making them more appealing. In many of the existing restrooms, the large stall that is wheelchair-accessible will become a larger space with its own door, toilet and sink. The airport will also label its new “family” restrooms as simply “restroom,” designated by signs with the symbols of a woman, child, man, transgender person and a wheelchair.

Single-user bathrooms may eventually become a bigger part of the airport makeover. “As people get used to them in other places, they’ll start asking for them,” said Jens Rothausen-Vange, senior associate at Alliiance, a Minneapolis architecture firm, and co-author of a guidebook on airport restroom design.

“Restrooms are the biggest customer service issue that the airport gets complaints about,” he said.

Shoppers at Hy-Vee’s new supermarkets in New Hope, Oakdale and Lakeville can see the future in action. Women have four single-user restrooms, each with a private toilet, sink and locked door. Men get four of their own, too, with a toilet and separate urinal on an opposite wall to avoid the bugaboo most prefer not to think about — splashing from the urinal onto the nearby toilet seat. “From a privacy standpoint, they’re much more appealing than a cattle-call style of bathroom,” said Edeker, Hy-Vee’s CEO.

He said the transgender debate, which swept up Target Corp. after it declared this spring that people could use its public restrooms by the gender with which they identify, didn’t enter his mind when Hy-Vee built its first store with single-user bathrooms in Urbandale, Iowa, in 2012. Edeker said he thinks it solves the problem, though. Eighteen of its new stores have the new restroom design, and many remodeled stores incorporate them, too.

But costs and regulations stand in the way of the single-user bathroom push.

A 40-square-foot single-user toilet costs about $12,500 to build, while a single stall in a multiple-user bathroom costs about $4,300, said Mia Blanchett, a principal at HGA Architects and Engineers in Minneapolis. “It’s more cost-efficient to do stalls in a row, but everyone loves the single-users,” she said.

It’s possible, however, for single-user bathrooms to take up less space than multi-user bathrooms with an equal number of toilets. “With single-user stalls you can lose the corridors and the large wasted space in front of the stalls that has to be open area,” said Mary Coakley Munk, president of the American Restroom Association.

Building codes discouraged gender-neutral, ­single-user restrooms by not counting them toward the minimum number of toilets required in a public building, but that appears likely to change. In the 2018 edition of the International Building Code, which is likely to be adopted by the state of Minnesota, single-user, gender-neutral bathrooms will count toward the total number of required plumbing fixtures.

Blanchett said, “Building codes lag behind while society figures it out.”

Another problem may persist with single-user bathrooms: They take longer and cost more to clean.

Paco Underhill, an environmental psychologist and author of “Why We Buy: The Science of Shopping,” estimates that labor costs for cleaning could be as much as 30 percent higher.

“Cleaning eight single-user bathrooms is harder than cleaning two multiuse ones,” he said. Still, when a single-user bathroom needs to be cleaned or repaired, it’s a lot less of an inconvenience than closing a multi-stall restroom.

Despite the extra cost, Underhill said that change is happening, especially when women are in charge. “Virtually every woman has had to stand in line to use the restroom,” he said. Single-user bathrooms increase the chance that no one has to wait in line.

At the Cafe SouthSide in Minneapolis, Anderson said the bathroom doesn’t need a politically correct label. “It just says ‘Restroom,’ ” she said.