Recently whilst on nights, driving through some thick Wiltshire fog on the ASP, I had to brake sharply to avoid an RAFP dog handler, who DPM clad, was patrolling the airfield. Nothing occured from the incident apart from a few choice phrases uttered, as I was driving at a safe speed. My worry is that someone less vigilant or driving faster may have had a very different outcome. Are there any iron clad rules to the wearing of high visibility vests/jackets or belts? All input appreciated. Atb techoz.