Safety factors
Research in 1969 by J. J. Leeming showed countries driving on the left have a lower collision rate than countries driving on the right.[29] It has been suggested this is partly because humans are more commonly right-eye dominant than left-eye dominant.[30][31][32] In left-hand traffic, the predominantly better-performing right eye is used to monitor oncoming traffic and the driver's wing mirror. In right-hand traffic, oncoming traffic and the driver's wing mirror are handled by the predominantly weaker left eye. In addition, it has been argued that left sided driving is safer for elderly people given the likelihood of their having visual attention deficits on the left side and the need at intersections to watch out for vehicles approaching on the near-side lane.[33] Furthermore, in a RHD car with manual transmission, the driver maintains his or her right (i.e. in the majority of people, dominant) hand on the steering wheel at all times and uses their left hand to change gear.
Cyclists and horse riders typically mount from the left hand side. This places them on the kerb when driving on the left.
I wonder about the facts and statistics, on Wiki they are still referring to a research from 1969?
