Thanks to everyone for contributing such an inventive range of clues.
With all of a possible 15 votes counted, the final tally is:
1 vote each for pigale @3 and dorrien @33
2 votes for FJ @5
4 votes for tatters @29
and a resounding 7 votes for bigbadmarty2 @17, with his clever and succinct
Stop at flashing amber before green light
Congratulations, Marty, here is your prize:
http://www.youtube.com/watch?v=NKUeQrV16A4
Cheers