Battery pack upgrade for Prius claims 150MPG

Being shown at the Clean Vehicle Technology Expo in Ontario, California is Hymotion's modified Prius that can hit up to 150MPG in city areas. By adding a 175 pound battery pack to the trunk of a Prius -- which fits conveniently under the floor panel -- and charging overnight using a regular power plug, owners will be able to drive for up to 50 miles on battery power alone: that's well over the average motorist's daily journey. It'll cost $9,500 including installation, but according to one of the staff at the show, half of that could be covered by rebates as part of a new electric cars bill soon to be before Congress. Onwards we go, tip toeing towards a petrol-free future.