I was wondering whatever happened to the potential for CNG buses. And I found this link <a href="http:&#x2F;&#x2F;cleantechnica.com&#x2F;2015&#x2F;06&#x2F;10&#x2F;electric-buses-beat-cng-buses-mile-nearly-6&#x2F;" rel="nofollow">http:&#x2F;&#x2F;cleantechnica.com&#x2F;2015&#x2F;06&#x2F;10&#x2F;electric-buses-beat-cng-...</a> which makes the case that they could be replaced by electric.