The purpose of reflective vests is to make people noticeable from long distance, as its bright color lights up with the sun reflection, keeping whoever is wearing one, safe from accidents.
To produce these special vests the fabrics must be polyester knit and windproof, another important characteristic is a breathable membrane. The reason for these specifications is that they are mostly worn in construction, or traffic roads, so the person who is wearing it is in constant danger of being hit by a car or machines that is why they are neon color.