Transportation
- In some countries, taxicabs are commonly yellow. This practice began in Chicago, where taxi entrepreneur John D. Hertz painted his taxis yellow based on a University of Chicago study alleging that yellow is the color most easily seen at a distance.
- In Canada and the United States, school buses are almost uniformly painted a yellow color (often referred to as "school bus yellow") for purposes of visibility and safety, and British bus operators such as FirstGroup plc are attempting to introduce the concept there.
- "Caterpillar yellow" and "high-visibility yellow" are used for highway construction equipment.
- In the rules of the road, yellow (called "amber" in Britain) is a traffic light signal warning that the period in which passage is permitted is coming to an end. It is intermediate between green (go) and red (stop). In railway signaling, yellow is often the color for warning, slow down, such as with distant signals.
Read more about this topic: Yellower, Symbolism and Associations