On September 3, 1967 Sweden switched from driving on the left to driving on the right.
As Dagen H neared, every intersection was equipped with an extra set of poles and traffic signals wrapped in black plastic. Workers roamed the streets early in the morning on Dagen H to remove the plastic. Similarly, a parallel set of lines were painted onto the roads with white paint, then covered with black tape.
On Dagen H, Sunday, September 3, 1967 all non-essential traffic was banned from the roads from 01:00 to 06:00. Any vehicles on the road during that time had to follow special rules. All vehicles had to come to a complete stop at 04:50, then carefully change to the right-hand side of the road and stop again before being allowed to proceed at 05:00.
On the Monday after Dagen H, there were 125 reported traffic accidents, compared with a range of 130 to 198 for previous Mondays. No fatal traffic accidents were attributed to the switch. However, many older people gave up driving rather than learn to cope with the new rule of the road. Experts had suggested that changing to driving on the right would reduce accidents, since people already drove left-hand drive vehicles, and would therefore have a better view of the road ahead. Indeed, fatal car-to-car and car-to-pedestrian accidents dropped sharply as a result. Some of the decrease was attributed to a reduction in speed limits by 10 km/h for some time after the switch. The accident rate rose back to its original level within two years.