Mercedes Ener-G-Force Concept

The Mercedes Ener-G-Force Concept  created for the Los Angeles Design Challenge 2012,  was designed as a highway patrol car for 2025, it boasts such outlandish features as a tank on the roof to store water that's transferred to the "hydro-tech converter" where it's converted into hydrogen for running the fuel cells and a 360-degree topography scanner on the roof.

 source:  uncrate.com