Dagen H (H day), today usually called “Högertrafikomläggningen” (“The right-hand traffic diversion”), was the day on 3 September 1967, in which the traffic in Sweden switched from driving on the left-hand side of the road to the right. The “H” stands for “Högertrafik”, the Swedish word for “right traffic”. It was by far the largest logistical event in Sweden’s history.
There were various major arguments for the change:
- All of Sweden’s neighbours (including Norway and Finland, with which Sweden has land borders) drove on the right, with 5 million vehicles crossing those borders annually.
- Approximately 90 percent of Swedes drove left-hand drive (LHD) vehicles. This led to many head-on collisions when passing on narrow two-lane highways, which were common in Sweden due to the fact that the country’s low population density and traffic levels made road-building expensive in per capita terms. City buses were among the very few vehicles that conformed to the normal opposite-steering wheel rule, being left-hand drive.
However, the change was widely unpopular; in a 1955 referendum, 83 percent voted to keep driving on the left. Nevertheless, on May 10, 1963, the Swedish Parliament (Riksdagen) approved the Prime Minister Tage Erlander‘s government proposal of an introduction of right hand traffic in 1967, as the number of cars on the road tripled from 500,000 to 1.5 million, and was expected to reach 2.8 million by 1975. A body known as Statens Högertrafikkommission (HTK) (“the state right-hand traffic commission”) was established to oversee the changeover. It also began implementing a four-year education programme, with the advice of psychologists.
The campaign included displaying the Dagen H logo on various commemorative items, including milk cartons and underwear. Swedish television held a contest for songs about the change; the winning entry was “Håll dig till höger, Svensson” (‘Keep to the right, Svensson‘) written by Expressen journalist by Peter Himmelstrand and performed by The Telstars.
As Dagen H neared, every intersection was equipped with an extra set of poles and traffic signals wrapped in black plastic. Workers roamed the streets early in the morning on Dagen H to remove the plastic. Similarly, a parallel set of lines were painted on the roads with white paint, then covered with black tape. Before Dagen H, Swedish roads had used yellow lines.
On Dagen H, Sunday, 3 September, all non-essential traffic was banned from the roads from 01:00 to 06:00. Any vehicles on the roads during that time had to follow special rules. All vehicles had to come to a complete stop at 04:50, then carefully change to the right-hand side of the road and stop again (to give others time to switch sides of the road and avoid a head on collision) before being allowed to proceed at 05:00. In Stockholm and Malmö, however, the ban was longer — from 10:00 on Saturday until 15:00 on Sunday — to allow work crews to reconfigure intersections. Certain other towns also saw an extended ban, from 15:00 on Saturday until 15:00 on Sunday.
The relatively smooth changeover saw a reduction in the number of accidents. On the day of the change, only 157 minor accidents were reported, of which only 32 involved personal injuries, with only a handful serious. On the Monday following Dagen H, there were 125 reported traffic accidents, compared to a range of 130 to 198 for previous Mondays, none of them fatal. Experts suggested that changing to driving on the right reduced accidents while overtaking, as people already drove left-hand drive vehicles, thereby having a better view of the road ahead; additionally, the change made a marked surge in perceived risk that exceeded the target level and thus was followed by very cautious behaviour that caused a major decrease in road fatalities. Indeed, fatal car-to-car and car-to-pedestrian accidents dropped sharply as a result, and the number of motor insurance claims went down by 40%.
These initial improvements did not last, however. The number of motor insurance claims returned to ‘normal’ over the next six weeks and, by 1969, the accident rates were back to the levels seen before the change.