The safest place on an airfield is the taxiway system....those airside roads are down right deadly!!
AFS, SOLO (Ambulance service) and Police are all allowed to free-range and will always give way to a/c. (When ATC see the vehicles with the 'blues' they tend to try and assist)
It's a system that works well; just watch out for those 'lost' policemen at night when they 'drift' onto the runway!
