Just before 7:45 a.m., on Broadway at West 155th Street in Washington Heights, the bus, which was not in service at the time, was traveling northbound on Broadway.
The bus jumped the curb and hurtled into a pizzeria, leaving several bystanders badly shaken and two badly hurt.
The bus driver told investigators he lost control after he was cut off by a minivan which then collided with his bus. Neither driver was seriously hurt.
Alex Sanchez, 25, was on his way to work and was thrown to the pavement while trying to protect his girlfriend.
"He tried to avoid his girlfriend from getting hurt. They were both laid down on the floor, holding hands. So far, he's alert but he has a cut across his head so we have to see," said Sanchez's sister Ana Mendez.
Kiera Pinero was working in the pizzeria when the bus crashed through the storefront.
"I'm still hearing myself scream!" she said. "I screamed and the next thing you know, there's a bus in the store. I was thinking to myself, oh my god, it's so surreal. I'm lucky I'm okay, the owner's okay, my co-workers are okay."
The crash is under investigation.