Högertrafikomläggningen, as it’s officially known (we’ll just stick with H-Day), took place on September 3, 1967. Besides the obvious danger of people simply forgetting which side of the road they should drive on, planners had to deal with the tricky issues of one-way streets and the relocation of bus stops, not to mention the reversal of some 360,000 signs across the country.
Intersections had to be reconnoitered to allow traffic to merge. The morning of the change, all non-essential traffic was banned from the roads, in some places from 10 am that Saturday until 3 pm on Sunday. Any vehicles that were on the road had to come to a complete stop just before 5 am, and were then guided to the right-hand side of the road to stop again before they were allowed to proceed.