R1: In a number of countries, cars drive on the leftSo here is a preliminary argument, R1 and R2
R2: This can result in accident involving drivers and pedestrians from other countries who are used to traffic being on the right.
IC: R3: Road would be safe if in all countries the rules were same.
R4: Countries where cars keep to the left are in very small minority.
C: Those countries should change to the right.