Pre-Timed Signal : Any type of traffic control device installed solely for the purpose of assigning right of way to emergency vehicles at locations where standard traffic control devices are unwarranted
Ilan Kelman (ed.), Vulnerability and Resilience Definitions and References, Version 2, 2007. http://www.islandvulnerability.org/docs/vulnres.pd f, (Vulnr and Resilience - Brit) {524}