angle
attention
background
blue
blue sky background
closeup
clouds
color
communication
concept
control
danger
direction
highway
icon
illustration
information
isolated
law
message
metal
nobody
object
octagon
outdoors
pole
post
prohibit
red
road
roadside
roadsign
safety
shape
sign
signal
sky
speed
stop
street
symbol
text
traffic
transport
transportation
travel
vertical
warning
white
word