The change known as "Dagen H" in Swedish was widely unpopular, and had repeatedly been voted down over the previous forty years. In a 1955 referendum, 83 percent voted to keep driving on the left.
In 1963, the Riksdag approved the change and established the Statens Högertrafikkommission (state right-hand traffic commission) to oversee it. The commission implemented a four-year education program, with the advice of psychologists.
The major arguments for the change were:
1) All Sweden's immediate neighbours drove on the right, including Norway and Finland, with which Sweden has land borders).
2) Most Swedes drove left-hand drive vehicles. This led to many head-on collisions when passing on narrow two-lane highways, which were common in Sweden because of its low population density and traffic levels.
- 1967-09-03 Sweden begins driving on right-hand side of road (Dagen H)