Conspicuity refers to the attention-attracting quality of a signal and depends on the signal characteristics, the interaction of the signal with the background in which it is seen, and whether and where the driver expects to see it.

This synthesis includes a compilation of regulations regarding the installation of traffic signal displays from traffic signal guideline manuals and technical papers in North America, the United Kingdom and Australia, and current practices from across North America.

The following elements are discussed:

·         Placement (primary, secondary, auxiliary, pedestrian)

·         Signal head orientation (horizontal, vertical)

·         Lens type (halogen, LED, incandescent, etc.)

·         Lens shape (square, circle, diamond, arrow, etc.)

·         Lens size (300 mm, 200 mm, etc.) and lens orientation

·         Backboard colour

·         Use of reflective tape (use, colour, etc.)

·         Visors or hoods

·         Colour of backside of backboard