Anything installed to traffic lights must undergo strict QA & QC, and must satisfy various standards required by the law. Unfortunately I can not do anything about those at the moment, because this is just an idea prototype (with actual implementation) without any funding at all.

Blinking green light can be implemented as an additional small traffic light, just like those used for bicycles but only with a green lantern that would be installed lower, somewhere at the same height as driver's eyes. Another idea is to use a higher power green LED with directional lens so that when it blinks it shines directly into the stopped vehicle that is keeping still in front of the traffic light.

Both of these should be enough to catch an attention of oblivious driver even when they are not looking at it directly. Unfortunately we can't do anything about sleeping drivers :-)

Two inputs are required to decide if we should start blinking:

1. Enable (when traffic light is currently green)

2. Not-moving (if car is not moving)

When both conditions are satisfied the microcontroller should start blinking LEDs. We might also allow 0.5 or even 1 second delay before starting to blink, but this should be experimented in the field.