Sweden was a 'left hand drive' country until 1967, when it switched to the right in line with the countries with which it shares a border - Norway, Finland. The main border crossings would have had filters and single lanes but I'd have beeen more worried in the northern regions - rural, quiet, underpopulated and with scores of semiofficial and unmanned crossings. Imagine the trouble you could get have had there! When Sweden did change -- at 3.00am on 5 Sept 1967 -- traffic speeds were greatly reduced for twomonths to ensure that head-on collisions were minimised!