Investigation of new traffic signs, markings and signals. Volume 1: Laboratory experiments and road tests.

Traffic signs, markings and signals recommended for the 1971 manual on uniform traffic control devices were evaluated both in the laboratory and on the road to measure the recognisability of both standard and experimental signs. The strong preference of people tested was for signs that carry both symbols and letter. Standardization in traffic control devices was considered as a primary objective in the improvement of devices.