Types of reasonings

Reasoning can be non-critical, normative , positivist and so many.
    To a question such as 'why should we drive on the left side of the road' , some people may give reasoning such as 'because that is the requirement of law'. This is a non-critical reasoning where the reasoning being given is itself not explaining the cause but only stretching farther our reach from the causation.
     Some may give the reasoning that keeping on left side of the road will all the traffic in the same direction along the same line, thereby avoiding the cross-traffic. This is normative, where he is explaining 'what is ought to be', i.e., what is desired to be. Does it explain to us why the choice of 'left side' over the 'right side' to achieve what is desired?
      There can be reasoning of how in the historical perspective the design of the car in the early days lead to choice of left side over the right side. However this positivist, based on facts. But it misses out the legal requirement and the desires, the purposes.