Traffic control signal preemption and priority devices
Wis. Stat. § 347.385
in effect(1m) In this section:
(a) “Authorized emergency vehicle” means an authorized emergency vehicle as defined in s. 340.01 (3) (a), (c), (g), or (i).
(d) “Political subdivision” means a county, city, village, or town.
(e) “Snow removal vehicle” means any vehicle equipped with a snowplow or anti-icing equipment that is used by a political subdivision for snow removal and is operated by a political subdivision or the agent or lessee of a political subdivision.
(f) “Traffic control signal preemption device” means a device, located on or within a traffic control signal, that is designed to receive an electronic, radio, light, or sound transmission from an approaching vehicle that alters the normal sequence of the traffic control signal to provide or maintain a green signal for the vehicle to proceed through the intersection.
(g) “Traffic control signal priority device” means a device, located on or within a traffic control signal, that is designed to receive an electronic, radio, light, or sound transmission from an approaching vehicle to request that a green signal be provided or maintained for the vehicle to proceed through the intersection.
(i) “Transmitter” means a device that emits a signal for the purpose of activating a traffic control signal preemption device or a traffic control signal priority device.
(2m) An authorized emergency vehicle may be equipped and operated with lamps designed and used, or with any other transmitter designed and used, to activate traffic control signal preemption devices.
(2r) A snow removal vehicle equipped with oscillating, rotating, or flashing lights that is actively engaged in snow removal activities may be equipped and operated with lamps designed and used, or with any other transmitter designed and used, to activate traffic control signal priority devices.
(3m) The lamps authorized for use under this section may be any color and may be flashing, oscillating, rotating or pulsating.
(4) No operator of an authorized emergency vehicle may use a transmitter, including lamps under sub. (2m), except when responding to an emergency call, when pursuing an actual or suspected violator of the law, or when responding to, but not when returning from, a fire alarm.
(5)
(a) No person may operate upon a highway a motor vehicle, other than an authorized emergency vehicle or snow removal vehicle, that is equipped with a transmitter or in which a transmitter is located. This subsection does not apply to a motor carrier or person in the business of selling transmitters to authorized users who transports a transmitter in original, unopened packaging or in an inoperative condition in an enclosed storage compartment of the vehicle.
(b) No person may sell a transmitter except for use for authorized purposes as described in sub. (2m) or (2r).
(6) The authority responsible for maintenance of a traffic control signal may establish procedures for resolving conflicts between multiple requests for signal preemption or priority at a traffic signal, except that a signal preemption request from an authorized emergency vehicle must be given priority over any signal priority request.
Source: WI Statutes (Official Site)URL: https://docs.legis.wisconsin.gov/document/statutes/347.385Fetched: 10/7/2026