Another missed point is looking at the midsize to large "family car". The Hybrid Escape is the closest vehical and gets an average 31 mpg and if you have more then two kids it just doesen't have enough space. Your average minivan gets about 22 mpg on a good day. The hybrid vehical, and I'm guessing at this, will have a significatly lower mpg if it is towing or filled with adult size passengers and it's advantage will decrease futher if the vehical is larger. Deisel's are known for their torgue and power and will be needed for large family and comercial vehicals. Both technoligies HAVE to be further developed because both have a lot of advantages that we need to meet our various driving needs.