to share – to copy, distribute and transmit the work
to remix – to adapt the work
Under the following conditions:
attribution – You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.
share alike – If you remix, transform, or build upon the material, you must distribute your contributions under the same or compatible license as the original.
When I first noticed these stoplights specifically for bikes in the bike lanes in NYC, I was very impressed and I thought it must mean the city is very bike-friendly. After biking around a bit I've determined that it is not as bike-friendly as I would like, but by biking around I'm hoping I'm helping to change that in a small way.