Two police officers have been given written warnings after a pursuit ended with a stolen car colliding with several vehicles in Somerset.
An inquiry overseen by the Independent Police Complaints Commission found officers ignored an order from their control room to stop the pursuit.
Police said another four officers had been given "words of advice".
The crash happened on the A38 at Langford Bypass, near Churchill, in 2008 but no-one was seriously hurt.
The investigation was carried out by Avon and Somerset Constabulary's professional standards department.
The 10-minute pursuit, which involved three marked and three unmarked police cars and the force helicopter, took place on 14 November 2008.
An Independent Police Complaints Commission (IPCC) spokesman said the Crown Prosecution Service (CPS) advised there was insufficient evidence to charge the officers.
The spokesman said that there was a suggestion from CCTV footage that an officer had assaulted one of the occupants of the stolen Volkswagen.
He said the CPS and the force had thought the use of force was appropriate and no complaint of excessive force had been made.
The driver of the vehicle, which was stolen in Bristol, was charged with burglary, dangerous driving and aggravated vehicle taking and sentenced to three years in jail after a trial.
Rebecca Marsh, the IPCC's commissioner, said: "Fortunately, nobody was seriously hurt as a result of this pursuit, but the reckless disregard of an order to abandon the pursuit could have had serious consequences.
"The force took this matter seriously and their response suggests that the public in Avon and Somerset can have confidence that any police pursuit will now be carried out strictly in line with force policy."
Anthony Bangham, Avon and Somerset Constabulary's assistant chief constable, said: "We co-operated completely with the IPCC investigation and were actively involved in it throughout.
"We acknowledge its findings, and we have worked hard to ensure that we have learned from this experience, and we continue to further improve our procedures around pursuit management.
"We always put public safety first in these circumstances, and it should be remembered that our officers are routinely called upon to make difficult operational decisions under very challenging circumstances."