RSA 266, Equipment of Vehicles, contains many sections relating to what types of lighting equipment various vehicle types must have and when they can be used. Examples are: use of blue lights is restricted to law enforcement and emergency response (RSA 266:78-b), use of red lights is restricted to police, fire and rescue (RSA 266:78-c), when law enforcement (RSA 266:78-f) and fire, rescue, and emergency personnel (RSA 266:78-g) should use their emergency lights, use of amber warning lights (RSA 266:78-h), use of wing lights on snow plows (RSA 266:78-j), lighting for school buses (RSA 266:39), use of purple lights for funeral processions (RSA 266:78-m), type of lighting for parade use (RSA 266:78-n), and special wrecker lighting (RSA 266:109). RSA 266:78-c, II says that red lights are authorized for privately-owned vehicles of "full-time or volunteer firefighters employed by municipal, village district, or federal fire departments and forestry departments or forest fire wardens and deputy wardens when authorized by their department heads."
If you needed a reason to keep headlights, tail lights, etc. in good working order, the NH Dept. of Safety website linked to below may give it to you. Among other things, the website lists cases in which problems with vehicle lighting were used as justification for a stop.
The administrative rules from the New Hampshire Department of Safety have many, many rules about lighting on vehicles. For example: Fog lamps on school buses (Saf-C 1313.09); those flashing red lights used when a school bus stops (Saf-C 1306.03), how many fog lamps a vehicle may have (Saf-C 3215.05), and more detail about what color emergency lights can be and who can use them (Saf-C 3215.02) are just some of the topics covered in regulations.
The purpose of this chapter is to reduce traffic accidents and deaths and injuries resulting from traffic accidents. When a motor vehicle safety standard is in effect under this chapter, a State or a political subdivision of a State may prescribe or continue in effect a standard applicable to the same aspect of performance of a motor vehicle or motor vehicle equipment only if the standard is identical to the standard prescribed under this chapter. However, the United States Government, a State, or a political subdivision of a State may prescribe a standard for a motor vehicle or motor vehicle equipment obtained for its own use that imposes a higher performance requirement than that required by the otherwise applicable standard under this chapter.
The purpose of this standard is to reduce traffic accidents and deaths and injuries resulting from traffic accidents, by providing adequate illumination of the roadway, and by enhancing the conspicuity of motor vehicles on the public roads so that their presence is perceived and their signals understood, both in daylight and in darkness or other conditions of reduced visibility.
Please remember that this guide is for information purposes only and is not comprehensive.
It is intended as a starting point for research, to illustrate the various sources of the law, and to provide guidance in their use.
NH Law About ... is not a substitute for the services of an attorney.