Dallas Police Department (DPD) Traffic Practice Exam

Displaying red, white, or blue beacon, flashing, or alternating lights without authorization is unlawful because these colors are typically reserved for emergency vehicles and specific authorized situations. The use of such lights by unauthorized vehicles can create confusion on the road, as they may signal a police, fire, or medical emergency. Therefore, the law restricts these particular colors to ensure that only those who have been designated as emergency responders can use them, safeguarding public safety and maintaining order in traffic situations.

In contrast, other colors such as yellow for hazard lights are more general and do not carry the same connotation of urgency or emergency response, allowing them to be used by any vehicle without special permission. Amber turn signal lights are standard indicators for signaling turns and lane changes, and they are legal for all vehicles. Green fog lights, while possibly inappropriate in many contexts, do not have the same prohibitive legal stature regarding emergency use as the red, white, or blue lights do.