Like someone said in the hnews comments, this might work for auto transmission but with manual gearing you've got people using engine braking on hills.
Also like stated in the article the colouring is going to be an issue and trying to see some green lights whilst the headlights are on (full beam fog lights perhaps too?) doesn't seem practicable to me.
Possibly, and I'd be interested in some sort of 360° LED on top of a vehicle to indicate to pedestrians and other drivers alike of its (de)acceleration.
But jamming some non standard colours in what is a long term understanding on the front of a vehicle I can't really get with and would like to see the impact to people with partial / colour blindness with using such a system.
Like, does the average pedestrian know what the green and red lights mean on an aircraft? I bet not.