In the US, trucks emit about 7% of greenhouse gases – compared with 17% coming from cars and light trucks.  But, just as the government is pushing to reduce the carbon emissions of cars by moving them into electric, higher mileage, etc., there is coming pressure to move trucks into better/different fuels than diesel.  New rules go into effect in 2021.  Europe already adopted “Draconian” rules in 2019 that require a 30% reduction in carbon footprint by 2030.  For long-haul trucking, there is no current technology that reaches this goal – or even a roadmap that might work.  CNG or LNG gets 15% – so things like hydrogen fuel cells may be the only answer.  My solution:  for the long haul – get friendly with the railroads!