alert
attention
attention sign
background
blank
button
caution
circle
danger
direction
disallowed
do not
empty
entry
forbid
forbidden
hazard
highway
icon
illegal
illustration
indication
information
isolated
mark
no
no sign
not
prohibited
red
reflection
restriction
restrictive
risk
road
rule
safety
sign
sign stop
signal
stop
street
symbol
traffic
transport
transportation
warning
way
white