The Norwegians, two men and a woman, were driving on the E18 highway from Karlstad in western Sweden to Oslo on Sunday morning when they pulled level with a car that was swerving. The Norwegians tried to pull into the hard shoulder to allow the other car to pass, but then the Swede did the same.
Eventually, both cars stopped near Långserud, 70 kilometres from the Norwegian border. There, the Swede backed into the Norwegian car, a police spokesman told news agency TT.
Police were alerted at 5:30 am on Sunday. When the Norwegians got out of the car to calm down the Swede, he threatened to kill them. He said he had a pistol and demanded their money. The terrified Norwegians ran to the woods.
With the Norwegians having disappeared, the Swede set light to their car, before driving away at high speed. Twenty minutes later he crashed into a parked truck. He was taken from the scene in an ambulance, and was treated for burns sustained when he set light to the car, according to Norwegian paper Aftenposten.
The man, age 42 and from the Karlstad area, was detained by police later on Sunday, suspected of drink driving, criminal damage, assault, and using threats.
One of the Norwegians was taken to hospital with a broken leg following the attack.