against green
america
arm
attention
barrier
beacon
blinking
blue
ca
cable
california
caution
copy space
cross
crossing
danger
electric
electricity
electrified
flash
flashing
freight
icon
indicator
industrial
industry
infrastructure
journey
light
metal
movement
moving
nature
notification
passing
pole
post
rail
railroad
railroad crossing
railway
raised
red
road
safety
security
sign
signage
signal
signs
sky
stop
symbol
track
traffic
train
transport
transportation
travel
trees
trip
us
warning
way
white
wire