allow
blue
conceptual
cross
gantry
go
green
judgment
law
light
metaphor
motion
netherlands
opportunity
pedestrian
permit
post
railroad
railway
red
road
roadsign
rural
safe
safety
sign
signal
signpost
sky
speed
speeding
stop light
stoplight
street
traffic
trafficlights
train
transit
transport
transportation
travel
urban
vehicles
warning
way
white
wink
yellow