In 1968, the Singsaker Line and the branch line from Søndre Gate to Trondheim Central Station, was closed and replaced by buses (Line 63). The main argument at the time was that a tram required both a driver and a conductor, while a bus only required a driver, thus lowering the operational costs. This development was partially driven by the removal of regulations on car ownership in Norway in 1960, resulting in an explosion in the use of cars in Trondheim and thus falling passenger numbers on the trams. The tracks were simply paved over, and still exist under the streets. At the time of the closure Line 3 was operating at a 5-minute headway with 2.3 million passengers. One year after the buses had taken over the passenger numbers had dropped 30%, and the consequence was fewer and fewer bus departures resulting in fewer passengers. In the end the headway was reduced to 45 minutes. In 1974 the three public transport companies in Trondheim, all three owned by the city, were merged to create Trondheim Trafikkselskap (now Team Trafikk, part of Nettbuss).