I don't think any one of those things will contribute even .5% towards reducing injuries.
In a perfect world, they may contribute to reducing accidents through the rider being more visible. Also, consider the control groups. What percentage were sportsbikes, DS bikes, Scooters? 100/1 ratio of sportsbikes to others means more riders in:
a) non-luminous leathers
b) flashy helmets, certainly not white
c) most often found riding without lights (as it's very uncool).
So, in my estimation, their facts are skewed and their control groups are not a true representation of the cross-section of the motorcycle industry.
The BMW and Hein Gericke clothing all comes well shod with refective items in several conspicuous zones. In my opinion, the wearing of a relfective vest actually takes away the vastly better profile presented by the BMW jacket.
Lawrence