abstract
accident
area
attention
authority
background
banner
barricade
barrier
border
caution
cordon
crime
criminal
cross
danger
dangerous
dead
death
forbidden
illustration
isolated
line
murder
murderer
not
officer
perimeter
police
policeline
problem
protection
render
ribbon
risk
safe
safety
scene
secure
security
sign
stop
strip
symbol
tape
terrorism
violence
warning
yellow
zone