This affects both ELS and Non-ELS cars and is related to the bloom on the 'car.default.light.emissive' setting from visualSettings.dat. This setting affects vehicle emissive sources such as police lights, daytime car lights and taxi signs etc. The emissive bloom can only be produced if, in the graphics options, the Shader Quality and PostFX are set to at least High. The bloom as you say is only noticeable when up close to the emissive source but then diminishes as you walk away. What is seen as a workaround to this is the use of coronas positioned on the light bars in order for them to be visible from a distance. However, most vehicle creators don't set these up correctly, if at all. You'll notice the vanilla vehicles lights look good from the distance because the coronas have been setup well by R*. The other way of fixing this is to somehow change how the game produces bloom on emissive sources. I believe that if this bloom can be altered then it will be somewhere in the Timcyc files or the Ambient Occlusion files (SSAO, HBAO etc.).