Reducing friction, weight and drag are the keys to Shell's new 107mpg concept car. We take it for a spin If all petrol-powered cars were like the diminutive Shell Concept Car, we’d all be getting an effortless 100mpg-plus on the way to work, while our cars’ tailpipes emitted a third less CO2 than even the cleanest city car. These are the conclusions of a two-year project that has produced a three-seat prototype combining the talents of Gordon Murray’s prolific Guildford-based automotive design…