Eugene Gunderman, 28, from Old Windsor in Berkshire, admitted stealing the Audi which knocked over PC David Oram in Chorleywood last July.
At St Albans Crown Court he was jailed for four years and ten months.
Damon Denham, 27, from Old Windsor, admitted car theft and was jailed for nine months.
Gunderman, of Queens Close, who also pleaded guilty to attempted robbery, ABH and dangerous driving, and disqualified from driving for five years.
Both men's sentences will run consecutively with convictions they received last August at Guildford Crown Court for their part in a conspiracy to rob a jeweller.
The court was told Denham drove Gunderman to Berkhamsted, in Hertfordshire, on 10 July.
Gunderman had arranged to test drive a grey Audi RS6, being advertised for sale, but instead sped off in it from the owner's home in Upper Hall Park.
Drivers on the M25 saw the vehicle racing along the hard shoulder at speeds of between 70 and 100 mph.
PC Oram and PC Stuart Fraser later found it parked in a lane where it was driven at them by Gunderman, who knocked down PC Oram, running over the base of his lower back and up his shoulder, before speeding off.
The defendants were arrested after the car collided with a number of other vehicles.
PC Fraser said he thought his colleague "had been killed".
"I have never been so relieved in my career to see someone get off the ground .... I have no idea to this day how he escaped," he said.
Mr Oram said his back was "never going to be 100 per cent" but hoped to remain as a front line officer as long as his back allowed.
Chief Supt Bill Jephson praised both officers for continuing to pursue the defendants, despite Mr Oram's "significant injuries".
"This proves how dedicated our officers are in facing life-threatening situations in order to prevent crime and protect the public, and their bravery should be commended," he said.

Mr Gulen, who is in self-imposed exile in the US, is accused of establishing and running an "armed terrorist group".
He was once an ally of Turkish President Recep Tayyip Erdogan but has now been accused of plotting to overthrow the Turkish government - a claim the cleric strongly denies.
The US is thought to be unlikely to act on any extradition request.
The move comes amid a national crackdown on perceived supporters of the cleric.
Over 20 journalists working for media outlets thought to be sympathetic to the Gulen movement were arrested last weekend.
Eight of them were freed on Friday on the orders of a court in Istanbul. Those released include Ekrem Dumanli, editor-in-chief of Zaman newspaper.
Four others, including a TV station boss, remain in custody.
According to the BBC's Mark Lowen in Istanbul, it was expected that the authorities would go after Mr Gulen after having targeted those linked to him.
While the US and Turkey have an extradition agreement, the warrant is considered to be largely symbolic - and unlikely to be acted upon.
The relationship between Washington and Ankara has grown fractious, though they remain allies.
Mr Erdogan has faced criticism from international leaders and his opponents, who accuse him of authoritarianism and undermining free press.
Many abroad believe that the charges against Mr Gulen are politically motivated.
The wealthy cleric, who operates an international network of schools and businesses, has lived in self-imposed exile in Pennsylvania since 1999.
According to media reports, the prosecutor filing the arrest warrant accused Mr Gulen of leading an armed terrorist group - a charge that carries up to 15 years in prison.
Two men have been jailed after they stole a car which was used to run over a Hertfordshire police officer, leaving him seriously injured.
[NEXT_CONCEPT]
A Turkish court has issued an arrest warrant for the influential cleric Fethullah Gulen.