Technical Overview

Theory behind the high visibility safety clothing

Theory behind the high visibility safety clothing

People tend to associated high visibility safety clothing with ANSI 107 or EN471 standard garments.


How many of you would be willingly to wear this reflective safety vest in public? To be blunt, it is very ugly. Some people are forced to wear
it by law, because they don’t have other options of more safe and comfort alternatives.


There is a dangerous misconception that in order to be safe, you have to wear ugly garments. Many people would rather risk getting hit by a
car than wearing such clothing. Workers take off their ugly vests as soon as get off the work site.


September 27, 2011 

        BBC News  

 Bikers in rule change  protest

   -Planned regulations would  force bikers and scooter riders to wear bright high-visibility jackets and make modifications which could result in old bikes being banned.  

 When the EU attempted to impose these standards on the general public, the result was chaos. This is just one situation. September
2011, Ireland, thousands of bikers rallied together to protest “unjust” safety proposals. These bikers would rather risk getting hit by a car, than wear the vests.

The vision of safety reflective clothing has being tainted by poor standards. Those standards are a marketing tool for certain products
rather than public safety. As long as a false specification remains the vision of reflective safety, people will continue to relate hi-viz safety to ugliness.

Published Science has proven that there are safer and more fashionable designs. The theory will be introduced, and is easy to understand:



1. Luminance at critical detection distance


2. Observation Angle

Material with a high coefficient of retroreflection does not necessarily mean that it will deliver more light to driver’s eyes. What
the driver observes is the spillage of retroreflective light.

3. Entrance Angle


What the driver observes is a collection of
light from all entrance angles times their corresponding planer area.


Field Tests



1. UTMRI report

2.     2. 3M-  HFES 2005 1931-1934

Although the data is questionable, the shows both solid reflective material and area reflective fabric exceed the required critical safety detection distance of 140m.


3.   Balk, et al, Perception 37 (2008), p. 1279Practical consideration: Garments that have equal luminance but different design have significant differences in conspicuity enhancement performance



1. 3Levels  of retro reflective material

Three levels of performance of the reflective material in each garment are defined based on visibility by the types of vehicle encountered.

Due to the distance from eyes to lamps are different in different vehicles, the required observation angle shall be tested in angles based on types of vehicle expecting encountered.

2.    2. 4 Classes of reflection clothing

Four classes of performance of the reflective clothing are
suggested and depend
the required
viewing position based on the user’s activity

A proposed ASTM standard is developed based on the above theories. It
can serve as a tool to evaluate the performance and safety effect of the
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