The NHTSA will soon propose new rules that will classify trucks by size for fuel economy regulation. Smaller trucks would be have to meet tougher fuel efficiency standards than larger trucks. The NHTSA opted to focus on size rather than weight for classification of trucks for the new CAFE (corporate average fuel economy) proposal. There were concerns that weight-based regulations would encourage truck makers to build their vehicles heavier. Such a trend would become a safety issue, some sources said. While that makes sense, you could also say that by classifying trucks by size that manufacturers would build bigger trucks. Typically, bigger means heavier. While it makes perfect sense to further classify vehicles for the purpose of CAFE regulation, we wonder if there is a solution that doesn't encourage building bigger vehicles.