You might know yellow as PMS 116 (if printed as a spot color)…or CMYK 83/83/0/60 (when printing on paper)…or RGB 17/17/102 (for the web) or HEX #111166 (web color)…or good ole Y (as in roYgbiv).
They all mean the same thing: Bright, Happy, Energetic Yellow!
Yellow produces a warming effect, arouses cheerfulness, stimulates mental activity, and generates muscle energy. Bright, pure yellow is an attention getter, so you can see why taxicabs are painted this color.
Use yellow to evoke pleasant, cheerful feelings. Yellow is very effective for attracting attention, so use it to highlight the most important elements of your design.
Here is a fun link where you can find out more about the psychology of color!