Sweden changed from left to right-hand drive in 1967. In the U.S. Virgin Islands they drive on the left in spite of the fact that all vehicles are right-hand drive.
According to Kincaid, Sweden drove on the right prior to about 1736, when it switched to the left (no reason is known for this change). However, its neighbors Norway and Denmark have always kept to the right, and Finland has also kept right ever since its independence and probably during the period of Russian administration before that.
By the middle of the twentieth century, the Swedish government felt increasing pressure to change sides to conform with the rest of Europe. Anders Hanquist writes, "The problem with left-hand driving in Sweden was, of course, that all our neighbours already drove on the right side. There are a lot of small roads, without border guards, leading into Norway so you had to remember in which country you were. Another curiosity was that most of the cars running in Sweden were built for right-hand driving. That means that the steering wheel was on the left side. Even cars imported from Britain were built that way. Buses, however, had the driver on the right side."
A referendum on the question of introducing right-hand driving was held in 1955, with the vote being 82.9% against and only 15.5% in favour of the conversion (see referendum results). However, in 1963 the Swedish parliament passed a law on the conversion to right-hand driving. The change took place in the early Sunday morning at 5:00 on the 3rd of September 1967.
"The traffic conversion in Sweden was," says Hanquist, "very well prepared. A booklet with more than 30 pages was distributed to every household in the country. A special state authority, Statens Högertrafikkommision (national right-hand traffic commission) was set up to administer the conversion. All traffic with private motor driven vehicles was prohibited four hours before and one hour after the conversion. In some cities there was no private traffic for 24 to 29 hours. Soldiers were called out to participate in work to rearrange all traffic signs." Malcolm Roe recalls that "the roads were completely closed, apart from emergency vehicles, for a day or two while changes were made to road signs etc. Then a very low speed limit was applied which was raised in a number of steps. The whole process, if I remember correctly, took about a month."
John R. Nickolls recalls watching the event from England on BBC television. He reports that Cliff Michelmore of the BBC "Tonight" show presented a live programme from Stockholm on the night of the changeover. "At (I'm fairly certain) 10 o'clock at night he pulled to the right-hand side of the road, waited about 5 minutes for road signs to be changed (explaining what was going on the while) and then asked a nearby policeman if he could now go on. The policeman waved him on, and that was it."