Re: LHD Porsche
Lifted straight from wikipedia....
In the late 1700s, a shift from left to right took place in countries such as the United States, when teamsters started using large freight wagons pulled by several pairs of horses. The wagons had no driver's seat, so the driver sat on the left rear horse and held his whip in his right hand. Seated on the left, the driver naturally preferred that other wagons overtake him on the left so that he could be sure to keep clear of the wheels of oncoming wagons. He did that by driving on the right side of the road.
The British, however, kept to the left. They had smaller wagons, and the driver sat on the wagon, usually on the right side of the front seat. From there he could use his long whip in his right hand without entangling it in the cargo behind him. In that position, on the right side of the wagon, the driver could judge the safety margin of overtaking traffic by keeping to the left side of the road. Countries that became part of the British Empire adopted the keep-left rule too, although there were some exceptions. Canada, for example, where the maritime provinces and Vancouver (later to become British Columbia) drove on the left, eventually changed to the right in order to make border crossings to and from the United States easier. Nova Scotia switched to driving on the right on 15 April 1923.
On most early motor vehicles, the driving seat was positioned centrally. Some car manufacturers later chose to place it near the centre of the road to help drivers see oncoming traffic, while others chose to put the driver's seat on the kerb side so that the drivers could avoid damage from walls, hedges, gutters and other obstacles. Eventually the former idea prevailed.
In Europe, the twentieth century saw a slow but steady shift from keep-left to keep-right. Portugal switched to the right early in the 20th century. Austria and Czechoslovakia changed to the right when occupied by Nazi Germany at the end of the 1930s, and Hungary followed suit. Sweden changed in 1967 and Iceland in 1968. Today, just four European countries still drive on the left: Britain, Ireland, Cyprus, and Malta. It should be noted that these are all islands, and therefore have no land border with countries that drive on the right.