The link that I put on was a link to the manufactures of BF-3 equipment. It is unique to Austria and Germany and is onley found on escort vehicles. In order to have one you need a licence. Their are two types of licence, BF-2 & BF-3. If you hold a BF-2 then your vehicle only operates with rotating beacons, and you can only escort vehicles up to a certain dimension. Anything bigger needs a BF-3 escort vehicle by law.
The signs displayed on the BF-3 board are classified as a legal road sign, meaning if a car overtakes when the BF-3 board is displaying a no overtaking sign, the overtaking vehicle is commiting an offence and can be prosocuted by the Polizi (german police).
The escort drivers of course have authority to stop and direct traffic, this is all part of the BF-3 licence.
PicsIt would be a very good idear if the UK could adopt something similar. Maybe, like germany a two-teir system. If you hold a catorgry A licence for example you have limited authority to stop and direct traffic and can only carry amber beacons, this is ideal for escorting smaller abloads like caravans ect. A catogory B licence gives you authority to temporly stop and direct traffic and also carry a similar idear to the german BF-3 device. At least when people see it they know catogoritly that theirs a big load up ahead. Of course to get something similar would mean a change in law and legislation, something unfortunaly is not likely to happen.
Rob