A system and method for signaling, marketing, and advertising alternative fuel-based vehicles that easily installs into new or pre-existing alternative fuel-based vehicles. In a preferred embodiment, the system comprises an electronic control unit (“ECU”) installed in the vehicle, which determines whether an internal combustion engine or alternative power source powers the vehicle. The system further comprises a driver display and in-car display both of which are connected to the ECU. The ECU monitors the power status of the vehicle and illuminates vehicle displays and transmits a signal to illuminate exterior advertising displays when the vehicle is operating on the alternative power source or in a fuel-efficient mode.