Have you ever witnessed a semi truck belching black smoke from its exhaust stacks as it struggles to maintain speed up a steep grade? If so, you've likely also witnessed the circus that ensues on the way back down the other side, as the truck picks up huge amounts of speed and momentum. This seems like the perfect situation to implement regenerative braking, and indeed, conceptual designs are being worked up for this exact scenario. The remote hybrid helper (RHH) would be used in hilly areas by semi trucks carrying heavy loads. The RHH attaches to the rear-most trailer and uses electric motors to push the truck uphill, then recaptures energy on the way back down.
Alternatively, the RHH could be used in heavy shipping lanes and ports, places where pollution is accumulating quickly. An opposing idea would be to integrate a similar system directly into the trailer chassis, eliminating the need for an additional hook-up but forcing the truck to haul heavy batteries on long, flat sections. With a bit more research and development, this could potentially be a winning concept.
[Source: The Greener Grass]