I am told that Left Hand Drive is marginally safer (all other things being equal) because of the preponderance of right-handed people. Driving on the left of the road places the right-handed driver's dominant hand on the wheel and dominant eye towards the centre of the road and oncoming traffic.

However this is not an argument in favour of 20th century style, non-autonomous individual vehicles as the main transit solution. There are safer and better ways. Autonomous Vehicles will hopefully play a role in that.