The American National Standards Institute (ANSI) determine safety policy and standards for a multiplicity of industry. At the same time as local regulations determine traffic safety vest policy, the broadly established standard is the American National Standard for High-Visibility Safety Apparel (ANSI/ISEA 107-2004).
Preface
The ANSI/ISEA 107-2004 standards categorize garment supplies into 3 classes. The personnel situation determines the mandatory of garment class.
Design
The ANSI/ISEA 107-2004 standard outlines the condition amounts of environment, reflective substance and assignment mandatory of the garment classes. Notice the Resources for a fast suggestion guide of these requirements.

Traffic Safety Vest

Class-I
Designed for personnel who are place back as of roadways somewhere traffic is less than 25 miles per hour. These garments are commonly vests.
Class-II
Designed for personnel who are place back as of roadways wherever traffic exceeds 25 mph or where poor weather conditions might obstruct visibility. These garments cover up the trunk.
Class-III
Designed for personnel in high-risk location, close to roadways anywhere traffic exceeds 50 mph or where poor weather conditions might obstruct visibility. These garments cover up the trunk and consist of arm or leg coverage.