The movement of a standard shock absorber creates heat, which is neutralized by the oil in the shock. In a PGSA, a linear electric motor converts the magnetic field created by the repetitive motion into electricity. Or, if you like your technology to sound science-y, it "uses an electromagnetic linear generator to convert variable frequency, repetitive intermittent linear displacement motion to useful electrical power."
The technology can be used on any vehicle that uses shocks and batteries, but its greatest application could be on trucks due to their higher mass and electricity-generation potential. Electric Truck, LLC has licensed the shock technology, which is predicted to generate between 2kW and 17kW of energy on an average road. According to the men who created it, "the percentage of recoverable power/energy for a 2,500 lb vehicle that employs four optimized design regenerative magnetic shock absorbers and whose average speed is 45 mph on a typical US highway is likely to be between 20% and 70%." Put four of those on a Prius and stay in town, and all of a sudden you're talking about interstellar gas mileage. Thanks for the tip, Paul
[Source: Gizmag via iCars]