crOsh,
Maybe you could modify your Arduino code to do simulate this idea (do they sell bi-color LED 7-seg displays?)...
Since I have only been working with the Arduino for a week, I think I'll leave that project to someone else for now.... :o
NetWorm,
In the city, the lights tend to go into hibernation and just blink yellow for everyone about 2-3 am. :
Go figure, make the street lights confusing just when all the drunks are driving home.... :o