Wis. Stat. § 347.26 — WI Code / Chapter 347 / Section 347.26
Restrictions on certain optional lighting equipment.
Status: in_force

(1) General restrictions. A vehicle need not be equipped with the lamps specified in this section, but if a vehicle is equipped with any such lamps, no person shall operate such vehicle on a highway during hours of darkness unless such lamps comply with the requirements of this section and no person shall use such lamps in a manner inconsistent with this section.

(2) Spotlamps.

(a) Any motor vehicle may be equipped with not more than 2 spotlamps.

(b) No spotlamp shall be used as a substitute for headlamps. No spotlamp shall be used as an auxiliary driving light on any motor vehicle except when such spotlamp is set or adjusted so that the rays of light are projected directly upon the road surface at a distance not exceeding 150 feet directly in front of the vehicle and to the right of the center of the traveled roadway. No spotlamp shall project any glaring light into the eyes of an approaching driver.

(3) Adverse weather lamps.

(a) Any motor vehicle may be equipped with not more than 2 adverse weather lamps which shall be mounted on the front of the vehicle below the level of the centers of the headlamps.

(b) Adverse weather lamps shall not be used in lieu of headlamps unless absolutely necessary in case of rain, snow, dust or fog and then only when a vehicle is equipped with 2 adverse weather lamps mounted on opposite sides of the front of the vehicle and when both such adverse weather lamps are lighted. Whenever any vehicle is equipped with only one adverse weather lamp, both headlamps of such vehicle shall be lighted at all times when such adverse weather lamp is lighted.

(4) Back-up lamps.

(a) Except as provided in par. (am) , any motor vehicle may be equipped with not more than 2 back-up lamps which shall be so directed as to project a white or amber light illuminating the roadway to the rear of such vehicle for a distance not to exceed 75 feet.

(am) In addition to the lamps authorized under par. (a) , a school bus that is painted as provided in s. 347.44 (1) may be equipped with one amber or white back-up lamp on each side. The lamps shall be mounted no more than 20 inches behind or 20 inches in front of the wheel housing area and below the floor line rub rail. The illumination shall be directed down and back for a distance not to exceed 75 feet. The secretary may prescribe rules for the specifications, installation, and operation of lamps authorized under this paragraph.

(b) No lighted back-up lamp shall be displayed on any vehicle upon a highway except when such vehicle is about to be or is being driven backward. Whenever a back-up lamp is lighted during hours of darkness, the tail lamp or tail lamps on the vehicle displaying such lighted back-up lamp also shall be lighted.

(5) Identification lamps on taxicabs and buses.

(a) No person shall operate a motor vehicle regularly used for transporting passengers for hire displaying any lighting device for identification purposes other than a single illuminated sign or lighted lamp mounted above the top line of the windshield, colored white, amber or green. Such illuminated sign or lamp shall be so constructed as to emit a steady or flashing nonglaring light.

(b) A school bus that is painted as provided in s. 347.44 (1) may be equipped with one illuminated sign mounted on the front above the windshield and one illuminated sign mounted on the rear above the window. The illuminated signs authorized under this paragraph shall emit a steady, nonglaring light.

(6) Warning lamps on tow trucks and service vehicles.

(a) Any vehicle which by reason of its use upon a highway creates a vehicular traffic hazard requiring the exercise of unusual care in approaching, overtaking or passing shall be equipped with a flashing or rotating amber lamp of the dome type at the highest practicable point, visible from a distance of 500 feet, or 2 flashing amber lamps, one showing to the front and one showing to the rear, visible from a distance of 500 feet and mounted approximately midway between the extremities of the width of the vehicle and at the highest practicable point. Such amber lamp or lamps shall be lighted when such vehicle is moving a disabled vehicle along or upon a public highway at a speed below the average speed of motor vehicle traffic on such street or highway and may not be lit at other times.

(b) Operators of tow trucks or towing vehicles shall equip each tow truck or towing vehicle with a flashing or rotating red lamp, in addition to flashing type amber lamps. Such lamp shall be placed on the dome of the vehicle at the highest practicable point visible from a distance of 500 feet. This flashing red lamp shall be used only when such vehicle is standing on or near the traveled portion of a highway preparatory to towing or servicing the disabled vehicle.

(7) Warning lamps on certain highway vehicles. Any vehicle of the department or a county or municipal highway department that by reason of its use upon a highway creates a vehicular traffic hazard requiring the exercise of unusual care in approaching, overtaking, or passing may be equipped with any of the following configurations of flashing red, amber, or green lamps:

(a) A lamp of the dome-light type.

(b) Two lamps, one showing to the front and one showing to the rear. The lamps shall be mounted approximately midway between the extremities of the width of the vehicle and at the highest practicable point and shall be used only for the purpose of warning operators of other vehicles of the presence of the traffic hazard.

(c) Four lamps, 2 showing to the front and 2 showing to the rear. The lamps showing to the front shall be mounted at the same level and as widely spaced laterally as practicable. The lamps showing to the rear shall be mounted at the same level and as widely spaced laterally as practicable.

(8) Warning lamps for mail delivery vehicles. Any vehicle used for mail delivery may be equipped with a flashing amber lamp or strobe light mounted at the highest practicable point and showing to the front and rear that may be used only to warn other motorists of the presence of a vehicular traffic hazard requiring the exercise of unusual care in approaching, overtaking or passing when the vehicle is being used to deliver mail.

(9) Warning lamps on public utility and cooperative vehicles.

(a) Subject to par. (b) , any vehicle of a public utility, as defined in s. 196.01 (5) , telecommunications carrier, as defined in s. 196.01 (8m) , or cooperative association organized under ch. 185 for the purpose of producing or furnishing heat, light, power, or water to its members that by reason of its use upon a highway creates a vehicular traffic hazard requiring the exercise of unusual care in approaching, overtaking, or passing may be equipped with any of the following configurations of flashing amber or green lamps:

1. A lamp of the dome-light type.

2. Two lamps, one showing to the front and one showing to the rear. The lamps shall be mounted approximately midway between the extremities of the width of the vehicle and at the highest practicable point and shall be used only for the purpose of warning operators of other vehicles of the presence of the traffic hazard. If the mounting of lamps midway between the extremities of the width of the vehicle is impracticable because of the vehicle’s design, then the mountings shall be made at or near the upper left front and rear corners of the vehicle.

3. Four lamps, 2 showing to the front and 2 showing to the rear. The lamps showing to the front shall be mounted at the same level and as widely spaced laterally as practicable. The lamps showing to the rear shall be mounted at the same level and as widely spaced laterally as practicable.

(b) In this paragraph, “maintenance and restoration of utility service” means the immediate restoration of a utility service that is outside the normal parameters of general maintenance or construction when damage or interruption of service has been caused to utility infrastructure by adverse weather or other events and that requires utility crews to park utility vehicles in the roadway or on the shoulder of the roadway. No person may use flashing green lamps under par. (a) unless the vehicle upon which the lamps are mounted is operated for the purpose of maintenance and restoration of utility service.

(10) Flashing amber light on oversize vehicle. Any vehicle moving on the highway pursuant to an oversize permit issued under s. 348.25 , 348.26 or 348.27 may be equipped with a flashing amber dome light upon the cab of such vehicle or with double faced flashing amber light mounted along the sides of such vehicle mounted and used when the movement is oversize.

(11) Flashing warning lamps.

(a) Any vehicle may be equipped with lamps which may be used for the purpose of warning the operators of other vehicles of the presence of a vehicular traffic hazard requiring the exercise of unusual care in approaching, overtaking or passing, and when so equipped may display such warning in addition to any other warning signals required by this section. The lamps used to display such warning to the front shall be mounted at the same level and as widely spaced laterally as practicable, and shall display simultaneously flashing white or amber lights, or any shade of color between white and amber. The lamps used to display such warning to the rear shall be mounted at the same level and as widely spaced laterally as practicable, and shall show simultaneously flashing amber or red lights, or any shade of color between amber and red. These warning lights shall be visible from a distance of not less than 500 feet under normal atmospheric conditions at night. Directional signals meeting the requirements of this chapter shall be used or lamps meeting these requirements, mounted so as to comply with turn signal installation.

(am) In addition to any other lamps authorized under this subsection, a motor truck having a gross vehicle weight rating of more than 26,000 pounds may be equipped with a 360-degree flashing or rotating amber light mounted at the highest practicable point. The flashing or rotating amber lamp may be lighted only when the motor truck is upon a highway having a maximum speed limit of more than 35 miles per hour and the motor truck is traveling 10 or more miles per hour below the maximum speed limit, is stopped, or is backing on such highway. The flashing or rotating amber lamp may not be lit at other times.

(b) Whenever any vehicle other than an automobile, which is equipped as permitted in par. (a) , is stopped for more than 10 minutes on the traveled portion of any highway, or shoulder thereof, during hours of darkness, the driver of such vehicle shall display warning signals as required by s. 347.29 .

History: 1977 c. 29 s. 1654 (8) (a) ; 1983 a. 53 s. 114 ; 1985 a. 204 ; 1989 a. 134 , 336 ; 1993 a. 496 ; 2005 a. 38 ; 2021 a. 255 ; 2023 a. 155 ; 2025 a. 208 .