People = Driving.
It's such a load of bollocks. This is basically cruise control. Let me remind you that using cruise control is about 5-10% less efficient in most cases than if you were modulating the throttle yourself.
What's more, who honestly cares about carbon emissions and miles per gallon THAT much? Ok sure we like an economical car but who would put their control down to a mobile phone..?
More CO2 is output from the few fossil fuel power stations in the UK, than all the cars do.. so instead of tackling things that people use every day (not that you don't use electricity every day), tackle things like using renewable energy to power our homes.
There was a government plan to implement a similar system, whereby it would automatically limit your cars speed to whatever speed limit you are in, not only making it hereby unsafe, it'd simply cause a collapse of the road system as we know it. 3 lanes of traffic all doing 70mph just would NOT work.
Just as here, having a system where a car would slow down, accelerate and the like for you isn't going to make travelling a) safer, b) more environmentally friendly or c) more pleasurable..
Cruise control is slightly different. It's a device which was fitted to make long distance motorway driving less irratiing by allowing the driver to relieve pressure on his/her foot/let. It's dis-activated the moment you press the clutch, or brake, so it's perfectly safe. It's not braking and accelerating around town.. which is not safe.