Countermeasures to Reduce Truck-Mounted Attenuator (TMA) Crashes: A State-of-the-Art Review
By Olugbemi Mosunmola Aroke - Download Here
This study is extremely technical but demonstrates that retroflective material enhances visibility of road workers to cars. And the more you use the better. Here are a few excerpts:
“Since work zone operations are usually obtrusive to the flow of traffic, it is important that work vehicles and equipment deployed within the work zones are highly visible to motorists. Lights and retroreflective tape enhance visibility and alert motorists to potentially hazardous situations. Retroreflective tape is recommended for use with flashing warning lights to highlight vehicle shape and increase vehicle conspicuity.”
“Retroreflectivity: Retroreflective tape markings (e.g., reflective red–silver adhesive tape) are effective in providing an additional level of warning for approaching vehicles. Although of limited benefit during the day, correctly applied and maintained retroreflective sheeting materials can significantly increase nighttime visibility and conspicuity of work vehicles.
"External light sources enhance the retroreflective properties of materials. Moreover, the degree to which a maintenance vehicle with retroreflective striping reflects light toward its origin is contingent on the amount of incoming light hitting the retroreflective surface and the specific viewing geometry of motorists"