GMC 1999 Sierra 1500 Pickup Owner's Manual page 185

't
KEEP LEFT
OR RIGHT TURN
RIGHT THROUGH
ONLY
AM402011
RECTANGULAR (square or oblong) signs show speed limits, parking
regulations, give directions, and such information as distances to cities.
Symbols on Road Sjgns
AM402012
There are many international road signs in use today.
The basic message of many of these signs is in pictures or graphic symbols.
A picture within a circle with a diagonal line across it shows what NOT to do.
NO U
TURN
NO
PARKING
NO BICYCLES
AM40201 3
4-7