abstract
asphalt
attention
backdrop
background
banner
barrier
black
border
building
caution
construction
danger
design
diagonal
dirty
frame
grunge
grungy
hard
hazard
hazardous
industrial
industry
line
metal
notice
obsolete
old
pattern
problem
road
rough
safety
sign
street
striped
stripes
surface
symbol
texture
traffic
transportation
urban
vintage
wall
wallpaper
warning
weathered
yellow