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 right-hand drive (RHD).
However, the change was widely unpopular; in a 1955 referendum, 83 percent voted to keep driving on the left. Nevertheless, on 10 May 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.
One-way streets presented unique problems. Bus stops had to be constructed on the other side of the street. Intersections had to be reshaped to allow traffic to merge.
The relatively smooth changeover saw a temporary 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.
Trams in central Stockholm, in Helsingborg and most lines in Malmö were withdrawn and replaced by buses, and over one thousand new buses were purchased with doors on the right-hand side. Some 8,000 older buses were retrofitted to provide doors on both sides, while Gothenburg and Malmö exported their right-hand drive (RHD) buses to Pakistan and Kenya. The modification of buses, paid by the state, was the largest cost of the change. In Gothenburg and Norrköping, and in two Stockholm suburbs, tram networks continued to operate.
Although all road traffic in Sweden became right handed, metro and railway systems did not switch to new rules and continue to drive on the left, with the exception of tram systems. Additionally, many of them were abandoned as a result of Dagen H; only the trams in Norrköping and Gothenburg and three suburban lines in the Stockholm area (Nockebybanan and Lidingöbanan) survived. Gothenburg had high cost for rebuilding trams, while Stockholm had cost only for bus purchasing, since the remaining lines had bidirectional trams with doors on both sides. In any event, most trams in Stockholm were replaced by the metro, a decision made long before the Dagen H decision.
- 50 år sedan: Så gick det till när Sverige fick högertrafik, Expressen, 1 September 2017
- Kommer du ihåg när Sverige fick högertrafik 1967?, Året Runt, 1 September 2017
- Réalités, Issues 200-205, Société d'études et publications économiques, 1967, page 95
- "Switch to the Right". Time. 15 September 1967. Archived from the original on 4 February 2007. Retrieved 25 September 2018.
- "Transport in Stockholm in the 1960s". Includes photographs of a RHD bus in Odenplan, 1962 and a RHD trolleybus in Vattugatan in 1964.
- News from Sweden, Issues 840-858, Swedish Information Service, Swedish Consulate General, 1963, page 35
- Riksdagens protokoll, Kungl. Boktr., 1966, page 8
- "Dagen H". Retrieved 2 October 2014.
- The Telstars - Håll dig till höger, Svensson, YouTube, 23 February 2013
- Sweden Makes Change-Over to Driving on Right, Glasgow Herald, 4 September 1967
- Et tu, Iceland? Another change to right hand driving, Autocar, 23 May 1968
- "Swedish Motorists Move To Right". Montreal Gazette. 5 September 1967.
- Adams, John (1985). Risk and Freedom: Record of Road Safety Regulation. Brefi Press. ISBN 978-0948537059.
- "Dagen H: The day Sweden switched sides of the road". Washington Post. 17 February 2012. Retrieved 2 October 2014.
- Behavioural Adaptation and Road Safety: Theory, Evidence and Action. CRC Press. p. 67. ISBN 978-1-4398-5667-3.
- Public transport was affected, 22 February 1997