Diffused Lights - Lighting Equipment - Vehicle - CA

Section § 25400

California law allows vehicles to have exterior lights that emit soft, non-glaring light at a low intensity. These lights cannot show red colors from the front and should not be placed too close to or interfere with other required vehicle lights or reflectors. Such lights are also limited in size and are meant mostly for vehicles used in business or residential areas.

Additionally, trolley coaches and buses in urban or suburban routes can have side signs with their own specific lighting restrictions, like not being too bright and avoiding white backgrounds.

(a) Any vehicle may be equipped with a lamp or device on the exterior of the vehicle that emits a diffused nonglaring light of not more than 0.05 candela per square inch of area.

(b) Any diffused nonglaring light shall not display red to the front, but may display other colors. A diffused nonglaring light shall not resemble nor be installed within 12 inches or in such position as to interfere with the visibility or effectiveness of any required lamp, reflector, or other device upon the vehicle.

(c) A diffused nonglaring lamp or device, other than a display sign authorized by subdivision (d), shall be limited in size to an area of 720 square inches and where any lease, rental, or donation is involved the installation of the lamp or device shall be limited to those vehicles operated either primarily within business or residential districts or municipalities, or between business districts, residential districts, and municipalities in close proximity.

(d) An internally illuminated sign emitting not more than 0.25 candela per square inch and possessing copy which does not contain a white background may be displayed on each side, but not on the front or rear, of a trolley coach or of a bus being operated in urban or suburban service as described in Section 35107 of this code.

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