I would consider paying $3500-$5000 more for a hydraulic vehicle because it would have more power and use less fuel that a traditional electric hybrid

C. David Burns

The advantages of hydraulics systems in general as opposed to mechanical and electric ones are that things can be placed more freely in the vehicle. For example drive the alternator, air conditioner, radiator fan, and water pump with hydraulics, and stick them in the trunk with rear wheel regenerative braking. Put the engine and and a hydraulic pump/motor and a hydraulically driven super charger in the front of the car. The engine unloaded from all the parasitic drags will rev very fast off the line and can be geared higher than normal since the first gear and reverse will basically be hydraulic. The hydraulic motors on the rear wheels will also allow for 4 wheel drive traction and the reduced drag of a driven wheel. Use a little exhaust turbine to run a high speed hydraulic pump if you want to get fancy. This avoids limiting the energy extracted from the exhaust by the turbine to what the inlet compressor can handle.

So the existing hydraulic hybrid are not taking advantage of the design flexibility allowed and so are not producing the benefits that would allow the hydraulics to earn it's keep by increasing the car's launch HP, tractive effort, improving weight distribution, and cutting down on it's quarter mile time.