abstract
attention
black
colorful
control
cross
crossroads
crosswalk
danger
design
direction
driving
electricity
element
equipment
flat
forbidden
front
graphic
green
guidance
highway
icon
illustration
isolated
lamp
light
object
proceed
red
regulate
regulation
road
safety
semaphore
sign
signal
stop
stoplight
street
symbol
traffic
traffic lights
traffic signal
transport
transportation
urban
warning
yellow