Green* = Go!
Amber = Go, but faster.
Red = Go, provided you are one of the first 3 cars to pass the stop line after the light turns red. (Otherwise reluctantly stop.)
* Incidentally the Japanese call green traffic lights ‘blue’. I once saw a chart comparing the green/blue hue of ‘green’ traffic lights around the world. Japan was very much at the blue end of the spectrum. Still reading? You nerd!