A window washer fell screaming 11 stories from a bank building Friday morning onto a moving car, crushing its roof and sending shattered glass flying into the street, police and witnesses said.

The window washer, who was not immediately identified, suffered critical injuries, but he was conscious, police said. He was taken to San Francisco General Hospital.

Witnesses described seeing a falling blue streak and the man's shadow as he fell down and then hearing a crashing sound as he hit the car and then rolled onto the ground.

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

The man 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.

Sam Hartwell, 56, of San Rafael, said he was walking to the Sterling Bank & Trust at California and Montgomery streets when the man fell. He and about 20 other people ran to the man, who was on his back.

"He was lucid. He understood we were with him," Hartwell said.

Hartwell said of his reaction, "It was utter, immediate shock. How do you react to something like that?"

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

No one else was injured, including the driver of the green Toyota Camry the man fell on. The driver did not want to comment, Newman said.

Blood, glass and one shoe were in the street as onlookers stood behind yellow police tape and watched officers work.

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.

Last month in Irvine, California, two window washers stuck for hours near the top of a 19-story high-rise were pulled to safety by members of a search-and-rescue team.

It was unclear how the workers became stuck on the side of the office building near the San Diego Freeway. Neither worker was injured, authorities said.

Also last month in downtown Oakland, California, two window washers were stranded outside the 19th floor of a high-rise for nearly two hours before employees inside realized they were in trouble and called for help. They also were not injured.