One day soon...

... all cars will be built this way. Jenny's "hybrid" car. Powered in part by electric motor and in part by internal combustion engine, you get this continuous read-out which tells you when the wheels are being powered by the batteries, or vice versa(if you are free-wheeling) and when they are being powered by the engine. Good job the scenery wasn't up to NZ's usual standards and I wasn't driving.