Q&A on retroflectivity with 3M

Glen Senior, human factors engineer, 3M Design and Vision Science, answered some of the top questions about garment visibility exclusively for Better Roads.

1. What are the different distances at which the different garments are typically visible?

The distances at which different garments are typically detected at depends on a number of things including: the environment the garment is in, the individuals cognitive load, did the viewer know that he/she was looking for a garment, etc.

2. May I have thoughts/insight on cognitive loads and enhanced visibility and how retroreflective materials (and those that aren’t) play a role in safety and identifying workers in construction zones?

High-visibility garments are thought to increase the contrast between the pedestrian and the background increasing the safety of workers by increasing the likelihood that the worker will capture viewer’s visual attention and increasing the likelihood of correct identification once the viewer does look at them. It has been shown that driver’s ability to detect road hazards (e.g., other cars) decreases as cognitive load of the driver increase. For example, Lamble, Kauranen, Laakso, and Summala (1999) found that increasing driver’s cognitive loads by having them talk on the phone or performing memory tasks decreased the distances at which they could detect road hazards.

3. How do the retroreflective garments provide enhanced visibility.

Retroreflective garments provide enhanced visibility by increasing the contrast between the pedestrian and the background. The high- visibility garments include components that increase contrast during daytime/nighttime/dawn/dust environments. Increasing the contrast between the pedestrian and the background increases the likelihood that the viewer’s attention will be drawn to the pedestrian and will be able to identify the object as a pedestrian if they do fixate on them. In addition to simply incorporating high visibility material (e.g., florescent materials and retroreflective material), the placement of the material at places that mark the torso and limbs aids in visual recognition of the individual. —Compiled by Tina Grady Barbaccia