The convoy of black cars rumbled along Connecticut Avenue, American flags flapping in the February breeze as the motorcade rolled past embassies and the homes of Washington's most powerful.

Drivers yielded for the SUVs flanking a long black sedan, not an uncommon sight in the nation's capital, as the vehicles zipped through intersections. But those gawking at the procession didn't have any idea it was just for a disc jockey who was running late.

"It was a surprise, but I like surprises," said Kimberly Venetz, who had a three-car convoy escort her to Bethesda on Monday as a part of a promotion from Uber, the car-for-hire service that randomly provided customers with "Ubercades" to mark the Presidents Day holiday. "It was fun. I've never done anything like this before. It was really cool," said Venetz.

But not too long before, a casually dressed Venetz was standing outside her apartment building waiting for a single black sedan and wondering the identity of the power broker who had come to visit her Northwest Washington complex.

"I was like, 'Man, who ordered this?' " she said. "And then when I realized it was for me. It was a shock."

Alex Priest, Uber's D.C. community manager, said the company had three Ubercades operating in the District on Monday and others in cities nationwide.

Monday marked the second consecutive Presidents Day that Uber surprised customers with motorcades.

Two young Uber employees conjured up the promotion about a year ago.

"It was just us talking about something cool we could do for Presidents Day," Priest recalled as he sat in the convoy's lead Chevrolet Suburban as it snaked through congested streets. "And then we said, 'Wouldn't it be fun to have a motorcade on Uber?' It was one of those shockingly simple ideas."

Priest bought a few American flags and, to complete the experience, coiled earpieces for the drivers.

Although the concept has its limitations -- the Metropolitan Police Department didn't perform its usual role of blocking traffic, and the Secret Service didn't chip in a counterassault team -- Venetz's Ubercade still drew plenty of gawkers, some of whom waved.

And nearby motorists took notice, too, allowing the convoy to stick together as it raced through traffic.

"With the Suburbans, people just seem to get out of your way," Priest said. "There's sort of a natural deference to the flags."