It is not built for speed. It burns through gas. And it is too big to park on any street.

But none of that matters when it is a 1952 Chrysler Imperial Parade Phaeton.

The open-air car in glossy black with red leather seats is New York City’s official parade car and the grande dame of the 30,000 vehicles in the nation’s largest municipal fleet. It stretches 20 feet from front to back to seat up to eight passengers, and it comes with its very own red-carpet floor. It has only one job: ushering V.I.P.s through blizzards of ticker tape on Broadway.

For more than six decades, its back seat has been filled with a who’s who of world leaders and celebrities. It gave rides to the Apollo 11 astronauts, the American hostages freed from Iran and the Yankees fresh off a World Series win — and another and another. It introduced the city to Van Cliburn, escorted John Glenn twice and ferried the kings and queens of Greece, Denmark, Thailand and Nepal through the streets.

“It’s really a piece of city history,” said Lisette Camilo, the commissioner of the Citywide Administrative Services Department, the official caretaker of the parade car. “It’s a touchpoint. It puts New York City at the heart of world events.”