Ok, folks, your claim is that there is not enough heat energy at exhaust gas emission to melt the snow, is it?
Your claim is based on "economical feasibility / efficiency" taught in our science logic today. But, today science is in contradictions. Just let me tell this. If the exhaust emission coming out of exhaust manifolds was not enough, how comes it drills the Ozone layer in atmosphere which is a hugh layer? Think collective science. Ok, Egon, exhaust gas of your tractor may not melt all snow around your house, but, then, you don't plow all snow around your house, either. What you do is just to plow a path for your walking and driving path. That's all. Exhaust gas will be enough to melt a path to your house and thats enough.
I will give another example on illogic in science logic today. They educate people solar energy is not efficient nor economical feasable. True that efficiency of solar systems today is really low. But, economically not feasable? It is for free. Give me New York. I will install solar collectors on a hill there and I will heat the whole NY, will supply electric energy to whole NY and all vehicles there will use electricity. So, whole energy of NY will be for free. What? Installation cost? Hey, collectors are made of aluminum, plastic, sand, etc. All these materials are under your feet and if you consider all these materials belong to you folks, they all will be for free. All to be done is to have 10,000 people who will work for 3 months for free to install solar collectors on the hill near NY city. But, if you gave all these materials to a few people and if their scientists are illogical, then, you will learn solar energy is inefficient, noneconomic, etc. All bs..