- Less pollution, as drivers can turn their engines off and cut carbon emissions while waiting for the green light,
- Less fuel consumption, as turning off vehicle engines lowers fuel consumption in the long run,
- Less stress, since drivers know exactly how long to wait, and
- Safer driving, as all traffic participants are fully aware of how much time they have left before the light changes, reducing the chance for potential traffic accidents.
Link, via Gizmodo and Reddit (where the discussion thread is decidedly less sanguine regarding the consequences of such lights).