In many countries you see number plates that are mostly white on the front and also white on the back. However in certain countries, and UK being a prime example, the rear plate is yellow . Now many including ourselves ask the question why is this rear plate yellow?
After the Black & Silver number plates in the UK, this style was introduced. We all know white number plates reflect very well and even the slightest light can make them shine bright in your face. Now this point we noted is that a yellow number plate, although is a good colour for being reflective, at the same time it does not shine bright into the driver behind you which can dazzle the driver.
The main point here for the colour was that it was illegal for white light to be shown on the rear of a vehicle, as it is bright and again for the sake of dazzling a driver, it was not allowed, hence the taillights of a vehicle. One exception to this rule was reverse lights which are white, an obvious choice to leave these white so if someone was reversing you clearly know they are reversing because there is a white light showing, a good decision to leave the only light white.
Finally, the choice of why yellow and not any other colour. This is a pretty simple and good choice when introduced. If you placed a black object over white, it shows well, the next best colour for placing a black object for it show well is on a yellow surface, hence the choice for yellow number plates on the rear of a vehicle, for them to clearly show, but not to show too bright which can cause discomfort to the driver behind you.