英文關鍵字
alert
animation
attention
background
barrier
black
border
boundary
build
caution
color
cone
cones
construct
construction
danger
equipment
forbidden
highway
icon
illustration
industry
isolated
marking
motion
object
obstacle
orange
plastic
reflection
repair
road
safety
security
sign
signal
simple
single
site
stop
street
striped
symbol
traffic
transportation
under
warning
white
work