ahead
alert
attention
background
black
caution
classic
concept
control
cross
crossing
danger
design
element
forbidden
graphic
icon
illustration
intersection
isolated
junction
no
object
obstacle
pictogram
rail
railroad
railway
road
route
safety
sign
silhouette
stop
street
symbol
track
traditional
traffic
train
transport
transportation
united states
vector
warning
way
white
yield