The Independent Police Complaints Commission says that Ann Barnes may have been driving without the right insurance on a number of occasions before the accident in Dartford in September 2014.
The commissioner was driving her own car, a Mercedes CLK, on her way to a Dartford Borough meeting.
Checks revealed that the car was insured and registered in her husband’s name and whilst Mrs Barnes was a named driver, the insurance policy related to social, domestic and pleasure use of the car only.
In the report, details of the policy states that the use of personal cars require the driver to have appropriate business insurance cover - suggesting that Mrs Barnes may have been driving without the right insurance.
The Kent and Medway Crime Panel has attacked the IPCC for taking 13 months to publish its inconclusive findings.
Ann Barnes maintains she was adequately insured and says the insurance company paid out on the claim.
The Crown Prosecution Service had decided in February 2015 that it would not be in the public interest to prosecute Mrs Barnes.