The shit hits the fan when wishful thinking comes into contact with reality. Here is a local example where substantial emissions reduction and energy savings could be achieved right now without recourse to any of the expensive, clunky, green paraphernalia currently being touted as Planet Savers. Just get rid of Collectivos, and mandate their replacement by buses, even electric ones if you want. Its as plausible a suggestion as some of the other ideas already mentioned in this thread.
Collectivos cause various flavours of contamination, in particular the cancerogenic emissions generated by diesel motors. Also they are an inherently energy-inefficient form of public transportation, and also cause other road users to waste energy through congestion.
But any government that wanted to change, or even regulate this "service" would have a fight on its hands, one that it would lose. Another Yellow Jacket scenario....