Gamma Scientificâs Highway-Safety Division and Advanced Retro Technology, two leading manufacturers of highway-safety measurement instrumentation, merged to create RoadVista. Through this , RoadVista becomes the largest, most comprehensive supplier of retroreflection-measurement instrumentation in the marketplace. Retroreflectometers and light measurement instruments from RoadVista are available for testing traffic signs, pavement markings, pavement markers, delineators, sign sheeting, high visibility clothing, headlamps, automotive sensors, and roadway lighting