The Day Sweden Switched What Side of the Road to Drive On
Dagen H (H day), usually called “Högertrafikomläggningen” – try saying that three times fast – became a very confusing day for the people of Sweden. To put “Högertrafikomläggningen” into terms that non-Swedish speakers can understand, it means ’the right-hand traffic reorganization’. On this particular day, September 3, 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. But why the sudden change? Most of Europe also drives on the left side of the road, so it’s strange that a European country would go against the grain.
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 behavior 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. To further confuse things, not all modes of transportation in Sweden changed which side they operate on. Although all road traffic in Sweden became right-handed, metro and railways did not switch to new rules and continued to drive on the left, with the exception of tram systems.