From parking attendants to a roadway construction crew, there are many types of workers who face hazards on and off the road. Safety vests and other hi-visibility safety garments are needed to keep workers visible during the day or night. The ANSI Standard 107-2004 establishes criteria for three garment classes based on amounts of garment background material and retroreflective material. The classes are also based on an assessment of worker hazards and tasks, making it easy for the wearer to select the appropriate garment for their work environment.

Class I Vest When permitting full and undivided attention to approaching traffic When providing ample separation of the pedestrian worker from conflicting vehicle traffic When permitting optimum conspicuity in backgrounds that are not complex, and where vehicle and moving equipment speeds do not exceed 25 mph Min. 1'' retroreflective band width 155 sq. inches of retroreflective or combined performance with background material

Class II Vest Traffic 25-55 mph When greater visibility is desired during inclement weather conditions Where complex backgrounds are present When employees are performing tasks which divert attention from approaching vehicle traffic When vehicle or moving equipment speeds exceed 25 mph When work activities take place in closer proximity to vehicle traffic Min. 1 3/8'' retroreflective band width 201 sq. inches of retroreflective or combined performance with background material

Class III Vest Traffic over 55 mph When workers are exposed to significantly higher vehicle speeds and/or reduced-sight distances When the worker and vehicle operator have high-task loads, clearly placing the worker in danger When the wearer must be conspicuous through the full range of body motions at a minimum of 1,280 feet (390 m), and must be identifiable as a person Min. 2'' retroflective band width 310 sq. inches of retroflective or combined performance with background material