Sweden Switches Sides ( Dagen H (H day) #Swexit

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.[1] The "H" stands for "Högertrafik", the Swedish word for "right traffic". It was by far the largest logistical event in Sweden's history.[2]

However, the change was unpopular; in a 1955 referendum, 83 percent voted to keep driving on the left

https://en.wikipedia.org/wiki/1955_Swedish_driving_side_referendum
A non-binding referendum on the introduction of right hand traffic was held in Sweden on 16 October 1955.[1]

The voter turnout was 53.2%, and the suggestion failed by 15.5% against 82.9%.[1] However, eight years later, in 1963, the Riksdag approved the change, following pressure from the Council of Europe[2] and the Nordic Council.[3] Traffic in Sweden switched from driving on the left-hand side of the road to the right on 3 September 1967 (see Dagen H).

https://www.bbc.co.uk/programmes/p045wh07

https://www.bbc.com/worklife/article/20180417-a-thrilling-mission-to-get-the-swedish-to-change-overnight?referer=https%3A%2F%2Fen.wikipedia.org%2F

https://en.wikipedia.org/wiki/H-dagurinn

https://en.wikipedia.org/wiki/Switch_to_right-hand_traffic_in_Czechoslovakia

https://en.wikipedia.org/wiki/730_(transport)

https://en.wikipedia.org/wiki/Left-_and_right-hand_traffic
https://notthegrubstreetjournal.com/2020/02/07/sweden-switches-sides-dagen-h-h-day-swexit/