background
black
blue
camera
cctv
city
control
electric
electronic
energy
equipment
go
green
guard
industry
isolated
lamp
lens
light
outdoor
power
privacy
private
protection
record
rejection
safety
security
semaphore
sign
signal
sky
spy
stop
stoplight
street
surveillance
symbol
system
technology
the road
the transportation
traffic
traffic light
traffic lights
urban
video
warning
watching
white