The state court in Saarbrücken found the 27-year-old motorbike mechanic guilty of the attacks on the morning of March 19th, when two passengers were wounded by some of the bullets he fired from a small wood near the town of Lebach.
Judges said that the man deserved an even more severe sentence than the one recommended by prosecutors given the seriousness of his crime and that they wanted the ruling to have a "deterrent effect".
Defence lawyers, who argued for a four-year sentence, said that they would appeal to the Supreme Court in Leipzig against the decision.
The accused admitted to the charges and apologized to each of his victims individually.
At the opening of the trial earlier this week, he said he didn't want to kill anyone and had been shooting at marker posts on the edge of the road.
But judges saw that as a "cover story" which was undermined by a study of the paths taken by his bullets.
One 41-year-old man who was struck in the arm by one of the shots said that he felt no "resentment or hate" against the shooter, but a representative for one of the other plaintiffs said they were happy that the court had decided for a harsh sentence.
The court heard that the 27-year-old had consumed large amounts of alcohol and illegal drugs before setting off for the woods to hunt.
But when he didn't manage to bag any game he started to shoot at cars, with judges saying that the inexperienced marksman was using them as "target practice".
As well as the attempted murder charges, the court found that the man was guilty of dangerous intervention in traffic, unlicensed ownership of a weapon and two counts of dangerous bodily harm.
The shootings led to mass fear in the Saarland region, with roads sealed off and local people remaining at home until police arrested the culprit.