An illustration: http://commons.wikimedia.org/wiki/File:Low_beam_light_patter...
I spent a year driving my English Right-Hand-Drive car on the roads in Spain, so I can sympathize with the Swedes and their worries about head-on collisions. Until you get used to it, it's pretty nervewracking passing oncoming traffic at 140kph and trying not to hit them while driving from the wrong side of the car.
Good practice though. At this point I'm pretty much ambidrivestrous .
People probably were paying extra attention, and that more than made up for the risk of people forgetting that today was the day.
It also mentioned they lowered the speed limit 10MPH, which saw a reduce rate of accidents as well for the two years until the raised the limit again.
"One German community removes lights and signs in a daring experiment and sees accident rates decline." http://www.csmonitor.com/World/Europe/2008/0912/p07s03-woeu....
Der Spiegel found seven affirming examples:
I always believed that driving on the left-hand side was safer because, a majority of the world's population is right handed. So, you want your good hand on the wheel, when you are changing the radio or using your stick-shift.
Other than for legacy reasons, right hand driving is harder than left hand. The easiest way to illustrate this is to learn to drive the stick-shift: it is easier on a left hand drive car (with your left hand on the stick-shift) rather than a right hand drive car
I even think it's the other way around: Holding the wheel is easier than changing some setting on the radio, because the latter needs "fine motor skills" whilst the first does not. It's preferable to use the hand with better "fine motor skills" - which in case of right-handed people is the right hand - for more complicated tasks.
When I was young, I drove a tremendous amount--pretty much 10-12 hours a day during the summer. We were wheat farmers, and the majority of that time was spent on a tractor. Because of the way that we went around the field, the right end of the plow started out next to the edge of the field. The best view of this was to sit facing the edge of the field (body turned to the right) so you can easily see ahead as well as the right edge of the plow readily. With a 32-foot plow, some degree of skill is involved in not overlapping already-plowed area (or taking out planted crop during the first round), and not leaving a gap between two rounds.
This meant that I did the bulk of the driving with my left hand, even though I am seriously right-handed.
And the result is that to this day, my left hand knows how to drive a straighter line than my right hand does.
Saint Thomas VI is all left side driving but all the cars have the driver on the left. As someone said at the rental place, it's so "you can talk to people on the sidewalk!"