I'm a bit disappointed that the Center for American Progress would be pushing natural gas BRT as a strategy instead of electrification with clean energy. They also have the fun generalizations about BRT such as "And construction of BRT systems cost 30 times less than a subway system" and "which operates like a subway system". I believe we've discussed this before in that once you get to the point where you're building real BRT the costs are much much higher than these 30 times claims.
If we're going to assume that BRT is a solution for heavy traveled corridors that aren't dense enough in riders for light rail, there is a case to be made for electrification and trolley buses in terms of public health (particulates) and energy (one power plant vs many). While CNG is much better than diesel, zero particulates should be the goal. We continue to see fossil fuel based solutions when we should be looking even further down the road.