attention
background
blue
car
caution
clouds
color
communication
concepts
control
danger
design
direction
forbidden
freeway
grass
green
highway
information
isolated
landscape
message
metal
navigation
nobody
object
octagon
outdoors
pole
prohibited
red
road
roadside
safety
security
sign
single
sky
speed
stop
street
symbol
text
traffic
transport
transportation
trip
warning
way
white