Class III safety vests provide the highest level of visibility and are designed for workers exposed to high-risk environments and traffic exceeding 50 miles per hour. Class III vests have sleeves and are made for all roadway construction personnel and vehicle operators, utility workers, survey crews, emergency responders, railway workers and accident site investigators. ANSI requirements also state that class III vests have 1240 square inches of background material and 310 square inches of reflective material.