Traffic signs and shapes

Red

“Stop” or “Prohibited”

Green

Movements permitted; direction guidance

Blue

Motorist services guidance

Yellow

General warning

Orange

Construction and maintenance warning

Orange (retroflective)

Used on various types of signs

Black or White

Regulation

Brown

Public recreation and scenic guidance

Horizontal rectangle

Generally for guide signs

Pennant

Advance warning of no-pass zones

Diamond

Exclusively to warn of existing or possible hazards on roads or adjacent areas

Verticle rectangle

Generally for regulatory signs

Pentagon

School advance and school crossing signs

Round

Railroad advance warning signs

Square signs

What you can’t do

Stop and Yield

Octagon = stop

Equilateral triangle = yield

Shapes only used for this purpose