Raj Mahay is launching a petition next month for a review into the death of his mother Kishni Mahay.
The 64-year-old was hit by a police car on Cannock Road, Wolverhampton, on March 14, 1989. The vehicle was responding to an emergency call.
The death was ruled accidental and an investigation by police said Mrs Mahay had run out into the road.
Mr Mahay, aged 54, claims key witnesses to the crash were never called. He also says a post mortem examination into his mother, which found cirrhosis of the liver caused by alcohol abuse, was wrong.
He says she never drank alcohol and the condition was caused by medication for tuberculosis and he claims evidence from the crash scene was tampered with.
This included his mother’s shoe, which he says was moved by a police officer.
The petition, which will be online, is hoped by Mr Mahay to attract 100,000 signatures.
This would mean the Government would have to consider the issue for debate.
Mr Mahay said: “I want justice for my mother. I’ve spent the last 29 years campaigning for this and will not give up. What I need is the support of people. Times have changed. Things went on before which would not happen now. All I want is the case to be looked at again.”
Mrs Mahay lived in Powell Street, Park Village. The driver of the police car was investigated at the time, but no action was taken.
At the inquest, the driver said he first spotted Mrs Mahay in the road when she was just a few feet in front of him.
He swerved violently to the right, but was unable to avoid the collision, he said.
He had been driving with the car’s siren and blue flashing lights on, at about 50mph, the inquest heard.
They were answering a call to an accident at the Park Lane junction with the Cannock Road.
The Police Complaints Authority oversaw the force’s investigation.
Detective Chief Superintendent Mark Payne, from the force’s professional standards department, said: “This is a tragic incident that occurred in 1989.
“In 2007/8, following representations from the Mahay family, a traffic collision investigator re-examined the case.
“They used techniques not available in 1989 to determine whether the original findings were correct.
“After applying these techniques, the investigator came to the view that the original findings were correct and therefore there was no rationale for any further investigation.”
He added: “At the time I had a meeting with Mr Mahay to explain the outcome, that there were no more investigative opportunities, and that the view of the assessor was that it was a tragic accident. I wish to reiterate my sincere condolences to Mrs Mahay’s family.”