I seem to remember that the Swedes always had LHD cars, so it was a bit easier for them to change over. It was talked about in the UK but the commonest argument ran on the lines of 'we've driven on the left for centuries and it was only Napoleon who changed it over, and Europe followed him'.

I've no idea if the bit about Napoleon is true or not.

Edit: Google is our friend....

Before the French Revolution, the aristocracy travelled on the left of the road, forcing the peasantry over to the right, but after the storming of the Bastille and the subsequent events, aristocrats preferred to keep a low profile and joined the peasants on the right. An official keep-right rule was introduced in Paris in 1794, more or less parallel to Denmark, where driving on the right had been made compulsory in 1793.

Later, Napoleon’s conquests spread the new 'rightism' to the Low Countries (Belgium, the Netherlands and Luxembourg), Switzerland, Germany, Poland and many parts of Spain and Italy. The states that had resisted Napoleon kept left – Britain, the Austro-Hungarian Empire and Portugal. This European division, between the left- and right-hand nations would remain fixed for more than 100 years, until after the First World War.

Edited by Avant on 25/04/2020 at 11:50

I've no idea if the bit about Napoleon is true or not.

The old explanation was that (a) most people were right-handed and defended themselves with a right-handed weapon; (b) therefore you rode on the left side so as to be able to lash out more effectively if needed. I don't know whether lefties therefore had an advantage, as in tennis.

As for Napoleon decreeing a change, I suppose that is possible, but it may have been some other conquering autocrat. The consequence of the Napoleonic wars in Iberia was that railways there were deliberately built with a wider gauge than in France, to make invasion by train more difficult. Modern Spanish TGVs run on a whole new set of trackwork.

Interestingly, British canal-boat traffic passes on the right - don't know why unless it's the rule of the sea.

The rule of the sea is to pass oncoming vessels 'port to port'

Overtaking vessels give one blast on the horn to signal they will pass on the right or two blasts if intending to pass on the left, the vessel being overtaken should respond with the same signals to show understanding.

Google will find a surprisingly long list of countries that drive on the left, Australia, Japan, South Africa and India, to name just four.