What happens when a country's entire transport system switches from left-side driving to right-side driving? On Sept. 3, 1967, Sweden made that exact flip-flop--and file photos show just how confusing the process looked.

Prior to the change, Sweden was the lone northern European country that still drove on the left. De Standaard notes that other Scandinavian countries already drove on the right and that many cars sold in Sweden had steering wheels on the left. While the country had ruled in 1916 that cars should drive on the left, parliament only enforced the change beginning in 1967.

The change was made at 0500 on Sunday 3 September 1967. All private traffic was banned between 0100 and 0600 and there was a total stop on all traffic at 0450, with a countdown on the radio to 0500. The speed limit in urban areas was lowered from 50km/h to 40km/h for a period of time after the change.
Some photos from the historic event:
Sweden changed from left-hand drive to right-hand drive at 5.00am on Sept. 3, 1967. The Traneberg Bridge, Stockholm, can be seen top, before and below after the changeover time. (AP Photo)

Traffic in a Swedish town is seen still moving on the left hand side of the road before the conversion to right-hand-drive with direction arrows already painted indicating the directions for right-hand-drive, August 12, 1967. (AP Photo)

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