advice
advisory
alert
attention
background
beware
black
building
button
careful
caution
construction
danger
dangerous
design
element
error
excitement
exclamation
fatal
gold
hazard
icon
illustration
industry
information
isolated
mark
message
point
precaution
red
reflector
risk
road
safety
security
shiny
sign
signal
street
symbol
traffic
transportation
triangle
triangular
warn
warning
white