Stockholm, 3 September 1967. What has just happened?

Dagen H (H-day), today mostly called "Högertrafikomläggningen" ("The right-hand traffic diversion"), was the day, 3 September 1967, on which 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".

Trams in central Stockholm, in Helsingborg and most lines in Malmö were withdrawn and replaced by buses, and over one thousand new buses were purchased with doors on the right-hand side.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 exported its 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.

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.