LHD,RHD??

Keeping to either the left or the right prevents vehicles moving in opposite directions from colliding with each other. This is so fundamental that it is sometimes known simply as the rule of the road. About 34% of the world by population drives on the left, and 66% keeps right. By roadway distances, about 28% drive on the left, and 72% on the right.[1]

In more sophisticated systems such as large cities, this concept is further extended: some streets are marked as being one-way, and on those streets all traffic must flow in only one direction. A driver wishing to reach a destination already passed must use other streets in order to return.

2006-12-17 11:38:07 補充：
History Archaeologists have unearthed a clue about ancient driving habits. In 1998 they found a well-preserved track leading to a Roman quarry near Swindon, England.

2006-12-17 11:38:16 補充：
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LHD-Left Hand Drive左軚
RHD-Right Hand Drive右軚