The objective of this study was to develop and test word and symbol traffic control and hazard messages for portable changeable message signs (PCMS). The messages were designed for the standard PCMS with three lines of eight characters. Each character is composed of 35 dots (7 high by 5 wide). For symbols a sign with a matrix of dots 16 high by 430 wide was used. Only single sign, non-sequential messages were tested. First, a comprehensive listing of candidate PCMS messages was developed. This was done by interviewing State highway engineers, surveying PCMS manufacturers and questioning motorists. More laboratory testing procedures was conducted. First the most effective key words or phrases were identified. Then the role of modifiers and cautionary messages was determined. In those situations where subjects did not express an overwhelming sign preference additional field testing was done. The detection distances of the candidate messages were determined using a PCMS under both day and night conditions. The study results were used to select a "recommended" message for each of 30 conditions where PCMS's could be used.
Abstract