It means that the highest court in the land has cleared the way for the EPA to do just about whatever it pleases when it comes to setting air-quality standards. In some cases, the rules could alter or completely extinct some forms of identified pollutant sources. It was just a matter of time until the EPA directed its attention to motorcycles. That time has arrived. Think about it - the white line is the life line of the nation.
Trucks move just about everything, everywhere, in the United States.
They are a huge piece of commerce. Yet, their run at reigning in the EPA has failed. Again, all is not lost - yet. But you need to start taking the responsibility which you have assumed as the rider of a motocross or off-road motorcycle seriously. We all want clean air.