Traffic control for maintenance on high-speed highways. Paper presented at the 53rd Annual Meeting of the Highway Research Board HRB, Washington, D.C., January 1974.

Observations were made at lane closures to compare effectiveness of yellow and orange signs. Results of the study tend to support the adoption of orange as the standard colour for signing construction and maintenance sites. However, differences between the two colours were rather small. Driver preference polls supported the orange signs more strongly. A degree of driver insensitivity toward signing was shown.