New York is the city that never moves.

Big Apple streets are clogged like never before amid a perfect storm of factors — including a building boom, record tourism, Donald Trump’s election and the holiday season.

Nelson Nuñez, 27, a driver for 1-800 Junk, had one word to describe the Manhattan gridlock: “Horrific.”

“The [Rockefeller Christmas] tree for one, our new president-elect, and it’s just not getting better,” he complained.

“Every day I plan my schedule differently. I have to take different routes, [it’s] just getting longer and worse. We are late right now, behind schedule, about two hours.”

“Gridlock” Sam Schwartz, a former NYC traffic commissioner, said traffic is already up 4 percent over last year — reaching levels the Big Apple hasn’t seen in at least a decade.

“This is the worst holiday season I’ve ever seen,” he declared.

Stiff security measures at Trump Tower have led to lane closures on Fifth Avenue, which not only affects traffic in one of the busiest areas of Manhattan, but other boroughs as well, Schwartz said.

“It serves the express-bus system, one of the major routes to Brooklyn, Queens, the Bronx and Staten Island,” he explained. “People will have to leave earlier to get to their various destinations on time.”

A veteran Manhattan firefighter said Manhattan traffic is so bad that members of the Bravest can’t respond to emergencies as quickly — and a delay of two or three minutes can be the difference between life and death.

“This is the worst I’ve ever seen it,” the firefighter said. “It’s causing a delay in response times, slowing us down and taking us longer to get to emergencies. Sometimes the fire engines are having a tough time even pulling out of quarters because of the congestion in front of the firehouse.”

“It’s not just Trump security, it’s everything from bike lanes to rush-hour traffic to new bus lanes,” he added.

Cops are complaining, too, saying they haven’t seen anything like it in ­decades on the job.

“I have a difficult time even finding an illegal spot to park my department car, so what chance does a person have of trying to find a legal spot?” a police source said.

“It’s the worst traffic I’ve seen in 25 years since I’ve worked in Manhattan. And traffic, with all these bikes and turning lanes and islands they put in between bus lanes, it’s an absolute nightmare.”

“When you get calls to go places, a burglary or grand larceny, or somebody gets hurt, by the time you get crosstown, it could take you a half-hour, 45 minutes,” he added. “It’s a logjam.”

A record 59.7 million visitors are expected to pour into the Big Apple by the end of 2016, and most of them will remain in Manhattan, despite efforts to lure tourists to the outer boroughs.

The Rockefeller Christmas tree, for example, is known for drawing extreme crowds:

New York’s building boom and massive projects like construction of the Second Avenue subway have led to traffic jams as well, experts say.

The city has also added pedestrian plazas and bikes lanes, and made left and right turns illegal at many intersections, all measures that tend to confuse drivers and gum up traffic, said AAA spokesman Robert Sinclair.

“The city is saturated with cars,” he griped. “Cab drivers, Uber drivers cut you off in the middle of traffic; they’re always trying to get a fare. People are always jockeying for a position.”

Manhattan’s traffic woes aren’t restricted to roads — sidewalk congestion is so bad that even pedestrians are moaning about it.

“It’s hard to walk around with my baby in Manhattan because the stroller is like a Suburban [SUV] on the sidewalk in a crowd,” said Shauna Cohen, 33, of Brooklyn.

Kathy Levine, 67, said she spends half the year in Jupiter, Fla., and the other half on the Upper East Side.

“I am actually leaving tomorrow,” she said. “I’d rather spend my holidays in peace rather than sitting in traffic or not being able to walk.”

Additional reporting by Kevin Fasick, Reuven Fenton and Elizabeth Rosner