allow
amber
background
blue
change
check
city
cloud
color
concept
control
cross
crossroad
drive
empty
environment
equipment
go
green
information
intersection
isolated
junction
light
no
recycling
red
road
safe
safety
semaphore
set
sign
signal
sky
space
stop
street
symbol
traffic
transport
transportation
travel
type
urban
warning
way
yellow
yes