Driver Interpretations of Existing and Potential Lane Control Signal Symbols forFreeway Traffic Management

摘要

The report documents the results of laboratory studies to assess motoristinterpretations of the following symbols used or initially seen as potential freeway lane control signals: red X, yellow X, green downward arrow, yellow downward diagonal arrow, yellow downward arrow, circle-slash (i.e., the universal 'do not' symbol), and a red X superimposed on a green arrow. The effects of flashing the red X, green arrow, and yellow arrows upon motorist interpretations were also evaluated. Results indicate that the red X and green arrow are well understood and convey a clear, consistent meaning to drivers. Also, the yellow diagonal arrow conveys a clear, consistent message to exit a lane. The yellow X and downward arrow elicited a wide range of interpretations by motorists, and these interpretations change depending on what other LCS symbols are present in an overall LCS array at a location. Flashing displays were not found to significantly affect motorist interpretations.