Language & WorldFact
Sweden switched from left- to right-hand traffic overnight.
At 5 a.m. on 3 September 1967, every Swede suddenly drove on the right. In 1955, 83% had voted to keep left, but Norway and Finland drove right and over 90% of Swedish cars had left-hand steering. On Day H there were only 157 minor accidents. The caution faded: by 1969 accident rates were back to previous levels.
Useful: Big switchovers often go more smoothly than feared, because everyone is briefly hyper-alert.
Source: en.wikipedia.org