More important would be heavy truck replacement cycle and EPA considerations offsetting that somewhat. Move to NG is important but long term cyclicality (demand due to aging fleets) must drive things so to speak. Even something as weak as NAV may benefit.
I am buying the commodity itself. CMI p/e is too high imo. Nat gas is still near historical lows, that imo has much more room to run than CMI does. CMI could retrace back to it's low in a crash. Not worth the risk any longer. Buy Nat Gas instead.