The requirements for vehicle obs lights are quite clear but how many airports actually enforce them?
At my particular airfield, the norm seems to be a standard quartz halogen rotating beacon that would do justice to any motorway service vehicle!!
How many crews have been blinded by these things flashing away on top of the GPU tug while they are trying to start? Fair enough, for vehicles that regularly operate on runways and taxiways, the brighter the better, but for apron vehicles a nice gentle flash will usually suffice.