• Blue-tinted lights like these constitute a gray area in lighting law.retro car. headlights image by Anna Chelnokova from Fotolia.com
  
  There aren't many laws restricting how you can make you car look. As long as you're not impersonating a government official, then aesthetics are entirely up to you. Lighting is another area of popular customization but is subject to somewhat tighter regulations in regard to color, placement and flashing or "strobe effects." By and large, these laws exist to ensure that people know when you're coming and going, and whether or not you're a cop, firefighter or road-maintenance worker. Exact laws will vary by state, but some are fairly universal.
  
  

White Light

• In no situation may you have a white light directly visible from any direction but the front of your car. This is to ensure that other drivers don't see the light from a distance and assume that you're heading toward them. The only exception is reflected or "ambient light," which includes tag lights and, in many cases where they are allowed, white under-body neon where the tubes themselves are not visible.
  
  

Amber Lights

• In most cases, you're only allowed to display amber or yellow for side marker, parking or turn-signal lights. These lights advise caution and are generally used to tell other drivers that you're there. Construction crews and other permitted vehicles also use large amber lights to alert passersby to their presence. Individual state laws determine whether or not certain private and/or commercial vehicles (like the "escort" cars used to guide oversized-load trucks) are allowed to use revolving or strobing amber lights.
  
  

Red and Blue

• Red tells other drivers that you're either heading away from them or are stopping, which is why only emergency vehicles are allowed to have red light visible from any direction but from behind. Direct blue light is almost never permissible for non-emergency or police vehicles. In some states you can use some shades of blue under-body or accent lights, provided that the light source itself isn't directly visible.
  
  

Headlight Color

• Many modern projector and high-intensity headlights have a slightly bluish or even purple hue to them, and yellow headlights have had a cult following for years. State laws are often somewhat hazy when it comes to headlight color; there are many shades of "white," and many projector beams change color depending on the angle from which they are viewed. The only way to be sure that your headlights are legal is to look for their DOT certification number and make sure that its not specifically mandated against in your local jurisdiction.
  
  

Strobes

• Generally speaking, any flashing or "strobe" light is illegal unless you have a specific permit (as in the case of construction vehicles) or are driving an emergency response vehicle. However, like all lighting laws, this only applies if you activate them on the street; there's nothing to say you can't have strobes solely for parking lot displays and car shows.