Same thing happened to me a few years back. I bought a new diesel pickup (tier 4) and the thing stranded me in the middle of nowhere. The problem was I wasn't driving it fast enough to build up enough heat in order to let the system do a regen. So, 40 miles from a main road in the middle of the mountains it shut down and told me to "see dealer for service". Granted, being stranded for a mechanical issue can happen to any vehicle, emissions related or not. My frustration was that nothing was really broke, but driving anywhere other than on a highway led to an automatic shutdown. And really, how much pollution was I making idling around? Same thing has/is happening with equipment. My dad bought a new tractor a few months back. He mainly uses it for moving round bales and feeding cattle. It never really gets warm enough to do auto regens. He's had to park it, crank the throttle, and let it sit for 20-30 minutes to clear the warning lights. Where's the sense in that?