Aside from all the exhaust emissions you can simply state that your old truck are greener because they are "recycled". 70% of a vehicles life-time pollution comes from the mining for the steel, electricity to run the plants, the VOC's from the plastic manufacturing,the computers, the shipping of materials, the list goes on and on. A Prius actually pollutes more than our old trucks when you consider the environmental footprint and divide it by years on the road. Our trucks have been on the road for 60+ years, a new Prius may last 20. I would bet that if all things considered, our old trucks would win hands down.
