The 58-year-old driver had double-parked his black 2011 Ford Expedition on Madison Avenue near East 49th Street just after 11 a.m. and was opening the door for a passenger when he realized the car was in gear and rolling in reverse, police said.
He quickly opened the driver's door and got partway back into the car to step on the brake, but he accidentally hit the gas instead, police said.
As the SUV jumped backward, the driver was thrown from the car and pinned between it and a parked 2013 Ford Econoline van.
He went into cardiac arrest and was rushed to New York-Presbyterian hospital, where he was pronounced dead, police said.
The SUV continued to roll backwards, heading southbound against traffic on Madison Avenue, and veering across busy East 49th Street, witnesses said.
Mike Conlon, an engineering manager who works nearby, saw the unmanned car and rushed into the street, whistling to stop oncoming traffic — and then he hopped into the moving SUV to stop it, he and witnesses said.
“After a few whistles, I took it upon myself to jump into the vehicle to secure it,” said Conlon, 47, a Long Island resident who works at Tower 49 at 12 E. 49th St. "It seemed like the thing to do."
Passersby were stunned by Conlon's quick thinking.
"It was like Batman — it was amazing," said Phil DeVito, vice president of the Capital One bank on the corner of East 49th Street and Madison Avenue.
By the time Conlon stopped the van, it was within feet of crashing into a garbage truck, DeVito said.
Conlon said he barely had time to think before acting, but he's glad he got involved.
“I’m community-minded and that was really much of my motivation now when I think about it,” he said shortly afterward. “I didn’t want to see anybody else get injured in my community."