The Palm Beach Gardens Police Department reviewed video surveillance footage of the intersection where Williams' SUV was struck by another vehicle.
The driver, Linda Barson, was injured and her husband, Jerome, died two weeks later.
A police report initially alleged the seven-time grand slam champion was at fault for the incident, though she was not issued with any citations or traffic violations. There was also no evidence she was under the influence of drugs or alcohol, or distracted by an electronic device.
However, fresh evidence cleared Williams, although the investigation is ongoing.
"Based on the evidence obtained in the ongoing investigation, it has been determined the vehicle driven by Venus Williams lawfully entered the intersection on a circular green traffic signal, and attempted to travel north through the intersection to Ballenisles Drive," the police statement said.
"As Williams was traveling through the intersection, a Nissan Altima entered the intersection traveling south, and made a left turn in front of Williams' vehicle, causing her to stop advancing through the intersection to avoid a collision.
"The traffic signal then cycled to green, at which time Barson continued westbound and entered the intersection. The front end of Barson's vehicle collided the right front of Williams' vehicle."
Williams is into the fourth round at Wimbledon, where she will face Croatian Ana Konjuh.