A judge ruled the prosecution had not proved Sergeant Stephen Hulland was driving dangerously before the crash, on the A4 at Thatcham, in Berkshire, on 7 May last year, in which 27-year-old Lee Hawkins died.
Hulland was acquitted of causing death by dangerous driving and fined pounds 100 after he admitted careless driving.
The verdict, which means Hulland, 36, can continue his 19-year police career, angered Mr Hawkins' family. His father Ray, 52, said he was disgusted, claiming the decision gave police officers the right to 'kill at random'.
Reading Crown Court was told that Lee Hawkins died after he was hit by Hulland's car, on its way to intercept armed robbers. The call was later found to be a hoax. Mr Hawkins, of Newbury, Berkshire, drove through a green light and collided with Hulland's armed response vehicle.
Hulland, of Thames Valley Police Support Group, Reading, told detectives he believed he was driving in a controlled way and that the coast was clear for him to go through the red light.
Afterwards, Ray Hawkins said: 'I believe he was acquitted because he is a policeman. If you had reversed the situation and my son had done it, he would have been in prison a long time ago.'Reuse content