"John Williamson" wrote in message
...

I've read that travelling on the left was started because the Roman roads
were built to move soldiers, and if you want two groups of soldiers to
pass in opposite driections, both carrying their shields on their left
arms as shown in most pictures from the time, then if they pass right to
right, you can make the road at least a foot narrower, as the shields can
overhang the edge of the road, but would collide if the groups passed left
to left.

To be honest I doubt that. I would imagine that the "pass to the left" rule
was started when Rome was still just a city state and those to whom it
applied were mainly pedestrians within the city of Rome itself. Then it
would have spread with the Empire as there would be no reason to change it.
But, unless a Roman document entitled "reasons for passing to the left" ever
comes to light we'll never know for sure :-)

I've also read that Napoleon wanted to (a) confuse the opposition, and (b)
prove that France was so civilised that travellers didn't need easy access
to their swords to defend themselves from other travellers.

Well again, unless Napoleon left documentary evidence of his reasoning his
reasons will have died with him.

I remember my Dad telling me that traffic in Vienna (but not the rest of
Austria) still drove on the left right up to the Nazi occupation as it was
going to be too expensive to convert the tram system. Adolf, of course,
didn't care about the expense.

David.