alert
blue
board
circle
control
door
drive
enforce
forbidden
grunge
grungy
highway
icon
iron
law
legal
metal
no
not
object
one
parking
police
prohibit
prohibited
prohibition
red
regulations
restricted
road
round
rule
safety
shut
sign
stained
street
symbol
texture
town
traffic
transport
transportation
travel
urban
vehicle
warning
white
wrong