Locomotives have used hybrid technology since the 1930's. Locomotives have a large diesel engine coupled to a generator. The electricity generated turns the motors in the trucks.
The engines will be more efficient because they can be designed to run at their most efficient speed. The regenerative braking is more efficient because it allows you to convert some of your kinetic energy into electric energy to recharge your batteries -- the current braking systems create heat energy, which is waste.
I hope we do start to get reliable, powerful and fuel efficient vehicles -- takes money from those scumbag arabs.
Submarines ran on diesel and electric motors also.