Interchangeable display assemblies are provided. A frame is configured to interchangeably accept any one of a number of digital side assemblies, each including an electronic display, a number of static side assemblies, each including a poster cavity which accepts signage, and a number of cover side assemblies at a first portion and any other one of the number of digital side assemblies, the number of static side assemblies, and the number of cover side assemblies at a second portion thereof.

A first and second display assembly are moveably mounted to a frame. At least one of the display assemblies includes a cover, an electronic display located behind the cover, and a first and second channel. A fixed plate is attached to the frame and positioned entirely within a cavity located between the display assemblies and the frame. The cavity and the first channel are part of a closed loop pathway, while the second channel is part of an open loop pathway. The closed loop is sealed when the display assemblies are in a closed position, and the fixed plate is accessible when the display assemblies are in an open position.

A roof mounted vehicle topper includes an electronic display, a housing for said electronic display, and a cross bar. The housing is mounted to the cross bar which is configured for mounting to the roof of a vehicle. At least a portion of the cross bar is hollow. A power source for said electronic display is located outside of said housing. Electrical wiring extends from said power source, through the hollow portion of said cross bar, to the electronic display.

An LED control system is provided for connection to an LED lighting system via a power line to control the LED lighting system using commands formed by manipulation of frequency and amplitude of a signal transmitted over the power line. The signal may be for example a wave or a sequence of pulses. The signal may be provided in superposition with line power or the line power may be formed as the signal.

An interchangeable display system and method is provided. A first and second side assembly are each selected from a number of: digital side assemblies each comprising an electronic display, static side assemblies each comprising a poster cavity which accepts signage, and cover side assemblies. The first and second side assemblies are interchangeably mounted to a frame. When one of the side assemblies is in need of replacement, it is removed from the frame and a replacement is installed.

A vehicle lighting system is provided primarily for use with emergency response vehicles. The vehicle lighting system includes at least one luminescent planar sheet affixed to a vehicle's mounting surface. The luminescent planar sheet includes a non-luminescent printed circuit board in the shape of a letter or number which has a top surface of a color which contrasts with the mounting surface's color. The luminescent planar sheet includes a plurality of light emitting LEDs which are surface mounted upon the printed circuit board so as to be arranged in the shape of the desired letter or number with the LEDs covering no more than 20% of the printed circuit board's top surface. Preferably, the LEDs cover no more than 7% the printed circuit board's top surface.

A solar powered vehicle topper unit and systems and methods for the same are provided. A solar energy harvesting device is electrically connected to an electronic display within a housing. A support extends between the housing and the solar energy harvesting device such that a bottom surface of the solar energy harvesting device is located above, and spaced apart form, a top surface of the housing to secure the solar energy harvesting device in an elevated position. The solar energy harvesting device has a first footprint, and the housing has a second footprint which is smaller than the first footprint.

Systems and methods for solar powered vehicle mounted displays are provided. A solar energy harvesting device is electrically connected to an electronic display within a housing. The solar energy harvesting device is configured for mounting to a roof of a vehicle. A mounting support is provided for mounting the housing to another portion of the vehicle.

A solar powered VTU and systems and methods for the same are provided. A solar energy harvesting device and an energy storage device are electrically connected to an electronic display within a housing. A support extends between the housing and the solar energy harvesting device such that a bottom surface of the solar energy harvesting device is elevated directly above, and is spaced apart from, a top surface of the housing. The solar energy harvesting device has a first footprint, and the housing has a second footprint. The first footprint is larger than, and directly overlies, the second footprint.

A solar powered display assembly and systems and methods for the same are provided. A solar energy harvesting device is electrically connected to a display unit which is connected to an electrical grid. At least one structural member extends between a housing for the display unit and the solar energy harvesting device such that a bottom surface of the solar energy harvesting device is elevated above, and spaced apart from, a top surface of the housing such that shade is periodically cast on the display unit. The solar energy harvesting device has a first footprint, and the housing has a second footprint which is smaller than the first footprint.