ANSI safety vests and garments have become required just about everywhere. Often the ANSI Class required is determined by the state. In Virginia, for example, any road work requires a Class 3 garment. It seems most states are fine with Class 2.
ANSI/ISEA say this about ANSI safety vests: The ANSI Class 2 vest "includes additional amounts of high-visibility materials to allow design opportunities to define the human form more effectively." ANSI Class 3 vests "offer greater visibility to the wearer in both complex backgrounds and through a full range of body movements. Translation: Class 3 safety vests will have sleeves. Click here to read more about ANSI vests.