WASHINGTON — When Evan Wilder went flying onto the pavement during his bicycle commute one morning here, he didn’t have time to notice the license plate of the pickup truck that had sideswiped him after its driver hurled a curse at him. Nor did a witness driving another car.

But the video camera Mr. Wilder had strapped to his head caught the whole episode. After watching a recording of the incident later, Mr. Wilder gave the license plate number to the police and a suspect was eventually charged with leaving the scene of an accident.

“Without the video, we wouldn’t know who did it,” said Mr. Wilder, 33, who was bruised and scraped in the crash.