[Bobcat]

Don ... it could be used , but with current technology it isn`t cost effective. What we found was that the heavier the vehicle the better , as you need the stored energy to recharge the system . Diesels are also "better" as they don`t give 25 + mpg ... try about 3 to 4 mpg for refuse trucks . I would assume about the same for the UPS trucks . It would be difficult to show a payback on a gas car or truck with current technology . As you indicated , space is also a problem as the system components are pretty good size and weight .
Actually , it is really neat . The acceleration an be better then with the engine alone and in some cases we were able to get several start stop cycles before the engine had to be used to recharge the system ... which it did on the longer runs between stops .
Just think of this system as a huge hydrostatic drive with accumulators supplying most of the energy and being recharged by the engine ... the hydraulic motors are a motor / pump combo ... used as a pump as the vehicle decelerates to charge the accumulator and then as a motor to accelerate the vehicle from a stop with the flow from the accumulator.
Good idea , but not really cost effective just yet .