Painstaking technical detail about intersection limit lines, visibility and speeds has been discussed at the Wellington District Court, as a fire fighter defends a charge of careless driving.

John Klaphake was charged after colliding with an SUV when he drove through a red light on the way to a house fire in Newtown last year.

John Klaphake is defending the charge at a judge alone trial.

He said he had assurance from his officer in charge the way was clear and he was going slowly.

He said he's very careful when he drives and doesn't take risks, and he was aware he was going through a red light.

In cross examining the police officer in charge, his lawyer Chris Tennet, said there’s no evidence that shows which vehicle entered the intersection first.

Constable Vaughan Simpson has also described the conditions that day, saying the weather was fine and the road was dry.

The trial continues.