20471:2013
This standard applies to "High Visibility Clothing."
Motor vehicles, excluding motorcycles and mopeds, must be equipped with a clothing accessory marked with retro-reflective material. Decree No. 294/2015 Coll. provides examples of warning clothing in Annex No. 12.
One such clothing accessory is a vest.
Regarding the use of these accessories, § 19 of the cited decree states:
Pattern and Use of Clothing Accessories with Retro-Reflective Material
(1) Clothing accessories include fluorescent yellow or fluorescent orange-red jackets, coats, t-shirts, vests, or trousers, complemented with retro-reflective bands (hereinafter referred to as "warning clothing"). The retro-reflective bands and fluorescent areas must be appropriately placed and of sufficient size on the warning clothing. These conditions are met if the warning clothing complies with the relevant harmonized European standard1).
1) ČSN EN ISO 20471:2013. High-Visibility Clothing – Test Methods and Requirements
(Note: Decree No. 30/2001 Coll. referenced standard ČSN EN 471.)
Annotation of the Standard's Content
This international standard specifies the requirements for high-visibility clothing that can visually signal the presence of the wearer to vehicle operators or other mechanized transport means under all lighting conditions, both in daylight and when illuminated by vehicle headlights at night. It includes qualitative requirements for color and retro-reflectivity, as well as minimum areas and placement of materials on the protective clothing. This international standard is not applicable for situations involving medium and low risk.
Source: Road Transport Services Center, Inc.