The officer and others at the checkpoint gave evidence, but Richards did not, counsel Scott Jefferson yesterday arguing in his closing address that the Crown had not established beyond reasonable doubt that Richards was the driver, or had he been that he deliberately drove at Constable Blummont to cause the injuries.
Mr Jefferson questioned the evidence of car passenger Alana Mumby, the only person to say they had seen Richards driving - one of three accounts she gave, which included telling police she was the driver.
He said the Crown had "cherry-picked" from the versions available.
But Crown prosecutor Rebecca Guthrie said there was "layer upon layer" of evidence pointing to Richards, and what he did to the officer, who had set-up beside a lamp-post, in uniform with fluorescent jacket, beside his unmarked patrol car with the engine running was "very deliberate and callous".
In his evidence, Mr Blummont recalled the incident, saying he thought: "This is it, I'm dying."
At the start of the trial, Richards had pleaded guilty to a charge of wilful damage, for throwing stones at a woman's car when she refused to let him into her home after he yelled: "Hurry up and open the door. I've just run over a pig."
One of Richards' first appearances in a Hawke's Bay court was as a 17-year-old being sentenced to 10 months' jail in 2003 for offences including robbing a 91-year-old woman of a handbag as she pushed a supermarket trolley in the Taradale shopping centre.
The judge sentencing him at that time said it was "mean, cowardly offending".
Over the years he had become a member of Black Power and had the insignia tattooed on his cheek.