There is simply NO EVIDENCE (NONE!) that high-vis jackets have reduced injuries at ANY airfield... plenty of examples where baggage handlers or other ground-crew have been injured DESPITE wearing "high vis" jackets... they do not provide ARMOUR after all! This has been debated at length before.....
The trouble is that health & safety "experts" have set the precedent of high-vis as "de-rigeur" for airfield "safety" despite this lack of evidence, so when you hire such consultants they apparently have a tick-box for air-side safety and high-vis jackets...
Aaargghh!!
