Red is the international color of stop signs and stop lights on highways and intersections. It was standarized as the international color at the Vienna Convention on Road Signs and Signals of 1968. It was chosen partly because red is the brightest color in daytime (next to orange), though it is less visible at twilight, when green is the most visible color. Red also stands out more clearly against a cool natural backdrop of blue sky, green trees or gray buildings. But it was mostly chosen as the color for stoplights and stop signs because of its universal association with danger and warning. COUNT 5
QSN1 In what city did the standardization of red as a color of stop lights occur? ANS1 Vienna QSN2 In what year did nations standardize on red as a color for stop lights? ANS2 1968 QSN3 At what event did the color red become the standard color of stop lights? ANS3 Vienna Convention on Road Signs and Signals of 1968 QSN4 Red is the color of stoplights due to its universal affiliation with what? ANS4 danger and warning QSN5 At what time is red at its brightest? ANS5 daytime