Description: Moving work zones have fewer traffic control devices than stationary work zones and provide no buffer space for vehicles that encroach on a work zone. To improve the safety of moving operations, the Iowa Department of Transportation (Iowa DOT) created a six-inch fluorescent yellow-green (FYG) background for the work zone signs that are mounted on the back of work zone vehicles.
Undoubtedly the FYG background creates a clear contrast between the orange sign and an orange Iowa DOT truck that follows a moving work area. This study examined the impact of the signs improved visibility in encouraging drivers to make an early merge to the open lane prior to a lane closure.
The analysis of data indicates that overall right-lane traffic volumes, recorded during the seven days of data collection after the background placement, were two percent less than the traffic observed in the "after" condition. The study concludes that the difference between the right-lane traffic observed in the "before" and "after" conditions is indeed statistically significant at the 95 percent confidence level.
Report: MwSWZDI-2001-Kamyab-FYG_Backing_for_Work_Zone_Signs.pdf 457 kb (published 2001)
State conducting research: Iowa