But Justices of the Peace Ken Graham and Mark Sinclair found no evidence Mrs Greenough was in danger of being run into from behind, before being seen by a police officer in the middle of the Ti Rakau Drive-Pakuranga Rd intersection when the lights turned red.
Constable Andrew Coleman said he was watching the intersection from a median strip in Pakuranga Rd during the evening travel peak last May as two cars entered the intersection on right turns from Ti Rakau Drive against yellow lights.
He told the court that Mrs Greenough was driving a third car, which he noticed "smack in the middle" of the intersection as lights mirroring those controlling the Ti Rakau entrance to the intersection switched to red. Mr Coleman acknowledged that he had no view of the lights facing her car, and did not know how far back she was from the intersection when they went from green to yellow, but estimated she was travelling 1.5 seconds to 2 seconds behind the second car.
But after he stopped her, he decided to ticket her for driving through yellow rather than red lights, as both offences carried the same penalty and he was keen to avoid a long road-side debate.
Mrs Greenough defended herself but called fellow engineer and transport planner Urie Bezuidenhout to testify to challenges facing drivers caught in a "dilemma zone" of having to decide if they have enough time to stop safely before lights turn red.
The witness, who is researching the behaviour of drivers at traffic lights for a doctorate at Auckland University, said a yellow light was simply an indication that a signal phase change was about to take place and may not be noticed immediately.
Even if drivers knew how long the yellow phase lasted, which an Auckland Transport official told the court was four seconds at the Ti Rakau-Pakuranga intersection, that raised potential difficulties for calculating how much time was left to stop safely.
But Mr Graham said there was no evidence of any other vehicle following too close behind Mrs Greenough.