The logics and reasons behind Left hand drive and Right hand drive

Research in 1969 by J. J. Leeming showed that countries driving on the left have a lower collision rate than countries driving on the right.
Logic: 

• It has been suggested that this is partly because humans are more commonly right-eye dominant than left-eye dominant. In left-hand traffic, the predominantly better-performing right eye is used to monitor oncoming traffic and the driver's wing mirror (side mirror).
• in an RHD car (that drives on the left) with manual transmission, the driver has the right hand, which for most people is dominant, on the steering wheel at all times and uses the left hand (and left foot) to change gears.

So it seems driving on the left is safer, but is it natural? yes it is as we know that

• Cyclists, motorcyclists and horse riders typically mount from the left-hand side, with motorcycle side stands almost always located on the left. So it is natural for a passenger to sit in a car from left side.

Further more;
In road racing, most tracks are run in a clockwise direction, including those in countries with right-hand traffic, which have anti-clockwise roundabouts. Since more corners are therefore to the right instead of the left, using a right-hand drive car has an advantage both in the driver's view of a corner's apex, and also in the overall weight distribution, which would be toward the inside.

The first legal reference in Britain to an order for traffic to keep to the left was in 1756 with regard to London Bridge. The General Highways Act of 1773 contained a recommendation that horse traffic should keep to the left.
Countries that became part of the British Empire adopted the British keep-left rule; some have since changed to driving on the right, because they all have extensive borders with former French colonies which drive on the right.

All the arguments favor a left hand drive and a right hand car. But as we see the map above, why majority of countries drive on the right? lets ask Napoleon...

There is a popular story that Napoleon changed the rule of the road in the European countries he conquered from keep-left to keep-right. Because that Napoleon himself was left handed, or that Britain, Napoleon's enemy, kept left. Alternatively, troops passing on the left may have been tempted to raise their right fists against each other, Napoleon  ordered the military to stay on the right side, even when out of the country, so that everyone who met the French army had to concede the way. In the early 19th century, those countries occupied by or allied to Napoleon – the Netherlands, Switzerland, Germany, Italy, Poland, Spain – adopted right-hand traffic.
There was a movement in the 20th century towards harmonization of laws in Europe and there has been a gradual shift from driving on the left to the right. 

Now lets go to American history to find the answer.

In the late 18th century, the shift from left to right that took place in countries such as the United States was based on teamsters’ use of large freight wagons pulled by several pairs of horses. The wagons had no driver's seat, so a postilion sat on the left rear horse and held his whip in his right hand. Seated on the left, the driver preferred that other wagons pass 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 logic behind driving on the right seem weak and scientifically unsound but majority of countries started driving on right may be as opposition to then super power the Britain, and many started to drive left to become in harmony with neighbors. Still, in many countries who drive on right, trains are still run on the left as the earliest rail systems, almost everywhere, were built by Britishers. 

Further reading
Why do some countries drive on the left and others on the right?