The DVLA has deemed 4D Neon number plate designs as road legal if they conform to the government regulations. These rules are designed to ensure the plates are easy to read by authorities and other motorists during both day and night.Providing they conform to the rules regulating UK number plates, 4D plates are entirely legal to use on your car. For example, the acrylic characters must be presented in black on a white plate at the front of your vehicle and black on a yellow plate at the rear, both manufactured from reflective material. The characters must also follow the rules that dictate the measurements of letters and numbers, as well as the margins surrounding them.