A worker who fell 11 stories from a San Francisco building onto a moving car, crushing its roof and sending shattered glass flying into the street survived but was in critical condition.

The man fell screaming from the roof of a downtown building Friday, but was conscious when paramedics reached the area, police said.

He remained in critical condition at a San Francisco Hospital Friday night, officials said.

The car's driver, Mohammad Alcozai, was not injured. He told KGO-TV that he's happy to be alive especially after his car's roof almost completely collapsed in the accident. He said he is praying that the worker survives.

"I'm very happy that I didn't get hurt," Alcozai told the news channel shortly after the accident. "Hopefully he can make it. I pray for him that he can make it."

Alcozai said he saw something hit his car shortly after making a left turn.

Witnesses described seeing a blue streak and the man's shadow as he fell and then hearing shattering glass as he hit the car and then rolled onto the ground. The roof of the car, a green Toyota Camry, was smashed in, and the rear windshield shattered.

Bianca Bahman, who was on the corner where the man fell, said she looked up to see his shadow and ran for cover.

"As he was coming down, he was definitely screaming," Bahman, 31, a pre-medical student at San Francisco State University who was on her way to the gym, said. "It all happened so quickly. It was so instantaneous."

The man, identified by police only as window washer, was moving equipment on the roof of a bank building in the heart of San Francisco's financial district and not on a window-washing platform when he fell, San Francisco police Sgt. Danielle Newman said. The platform was on the ground at the side of the building, and cables were hanging from its sides. It was not clear whether the man was setting the platform up, but he was working with a partner, police said.

Bahman and about 20 other people ran to the man, who was on his back. The man was lucid, though he was bleeding.

The bystanders, who included a nurse, put clothing on the man as they waited for the ambulance.

The man worked for Concord, California-based Century Window Cleaning, said Peter Melton, a spokesman for the California state division of occupational safety and health.

The company was cited for one serious violation and three other violations in 2008, one of them related to instructing window-cleaning employees in the proper use of all equipment provided to them, and supervising the use of the equipment and safety devices to insure that safe working practices are observed, according to federal records. The company was fined more than $6,500, though the fine was eventually reduced to a little more than $2,700.

Recent incidents involving window washers show the dangers of the job.

Last week, the collapse of a World Trade Center scaffold left two window washers dangling from the nation's tallest skyscraper. The workers were trapped 68 stories above the street when a cable suddenly developed slack on Nov. 12.

The workers held on to the teetering platform for two agonizing hours. One called his wife during the ordeal, fearful that it might be his last opportunity to speak to her. Firefighters used diamond cutters to saw through a double-layered window and pulled the men to safety. They were not injured.