access
alert
approach
area
attention
barricade
barrier
beware
block
border
boundary
caution
civil engineering
closed
construction
danger
ditch
fence
forbidden
heed
hole
industrial
industry
keep out
manufacturing
obstacle
outdoor
passage
prohibition
protection
red
road
safety
secured
security
sign
signal
stop
street
stripes
symbol
traffic
trench
triangle
warn
white
work in progress
workplace
works
zone