Keith Collier, 50, was an over-protective "father figure" to Humble and had acted out of misguided loyalty to him, the court heard.
Humble, 33, was jailed for 12 years at the Old Bailey on Thursday for the manslaughter of Toby Exley, 22 and his girlfriend Karen Martin, 20, on 6 October last year.
He had rammed Mr Exley's Ford Fiesta three times with his three-litre Vauxhall Senator because it would not get out of his way on the outer lane of a dual carriageway. As a result, the Fiesta crashed through the wooden central reservation of the A316 at Hanworth, west London into the path of an oncoming car. The couple died instantly.
Humble did not stop but went straight home to the bungalow he shared with Collier in Farnborough, Hampshire.
He told Collier what had happened. The car was registered in Collier's name, said David Perry, for the prosecution.
There was local press coverage of the crash and the identity of the car and driver involved remained a mystery.
"There were appeals in the press for witnesses to come forward. On the 11th October, Collier went to Farnborough police station and reported the Senator stolen," Mr Perry told the court.
Collier admitted perverting the course of justice.
The Recorder of London, Sir Lawrence Verney, told Collier: "The conduct in which you engaged last October was deliberate. The time you went to the police station to make a false report of the theft of your vehicle, you already knew all the circumstances about the accident.
"You were prepared, out of a very misguided sense of loyalty to Humble, to pervert the course of justice and had no thought whatever for the bereaved families who wanted to know the truth. It is a charge which must cause the court very great concern."
Rodney Price, for the defence, said that Collier was a decent hardworking man - albeit overprotective. Rather than being callous, he tried to do his best for others. He first met Humble when the latter was 16 and had started work at the same garage where Collier was sales manager. Collier felt sorry for Humble, who had no father and whose mother committed suicide.
"The defendant, who is a bachelor, adopted the role of a father figure. He helped him over learning difficulties and to secure an apprenticeship."
The judge ordered that the car used in the attack should be sold and the proceeds given to charity.