NOTE: This information is dated 12/09/2014 and may become obsolete in the future
I’ve been researching the legality of strobe brake lights (sometimes referred to as wig-wags). I contacted the Polk County Sheriff Department to ask and they provided the Iowa Code below. I have highlighted the section of interest. It’s ambiguous at best, but it looks like they are legal by the “letter of the law”. I’ve contacted an attorney but have not heard back. Emphasis mine.
Of particular note is the “prohibited except” and the “intent to stop” language.
321.423 FLASHING LIGHTS.
1. Definitions. As used in this section, unless the context
a. “Emergency medical care provider” means as defined in
b. “Fire department” means a paid or volunteer fire
protection service provided by a benefited fire district under
chapter 357B or by a county, municipality or township, or a private
corporate organization that has a valid contract to provide fire
protection service for a benefited fire district, county,
municipality, township or governmental agency.
c. “Member” means a person who is a member in good standing
of a fire department or a person who is an emergency medical care
provider employed by an ambulance, rescue, or first response service.
2. Prohibited lights. A flashing light on or in a motor
vehicle is prohibited except as follows:
a. On an authorized emergency vehicle.
b. On a vehicle as a means of indicating a right or left
turn, a mechanical failure, or an emergency stop or intent to stop.
c. On a motor vehicle used by a rural mail carrier when
stopping or stopped on or near a highway in the process of delivering
mail, if such a light is any shade of color between white and amber
and if it is mounted as a dome light on the roof of the vehicle.
d. On a vehicle being operated under an excess size permit
issued under chapter 321E.
e. A flashing blue light on a vehicle upon which a blue light
is permitted pursuant to subsection 3 of this section.
f. A flashing white light is permitted on a vehicle pursuant
to subsection 7.
g. Flashing red and amber warning lights on a school bus as
described in section 321.372, and a white flashing strobe light
mounted on a school bus as permitted under section 321.373,
h. A flashing amber light is permitted on a towing or
recovery vehicle, a utility maintenance vehicle, a municipal
maintenance vehicle, a highway maintenance vehicle, or a vehicle
operated in accordance with subsection 6 or section 321.398 or
i. Modulating headlamps in conformance with 49 C.F.R. §
571.108 S7.9.4. are permitted on a motorcycle.
j. On a vehicle being operated as an escort vehicle for a
funeral procession as provided in section 321.324A.
3. Blue light. A blue light shall not be used on any vehicle
except for the following:
a. A vehicle owned or exclusively operated by a fire
b. A vehicle authorized by the chief of the fire department
if the vehicle is owned by a member of the fire department, the
request for authorization is made by the member on forms provided by
the department, and necessity for authorization is demonstrated in
c. An authorized emergency vehicle, other than a vehicle
described in paragraph “a” or “b”, if the blue light is
positioned on the passenger side of the vehicle and is used in
conjunction with a red light positioned on the driver side of the
A person shall not use only a blue light on a vehicle unless the
vehicle meets the requirements of paragraph “a” or “b”.
4. Expiration of authority. The authorization shall expire
at midnight on the thirty-first day of December five years from the
year in which it was issued, or when the vehicle is no longer owned
by the member, or when the member has ceased to be an active member
of the fire department or of an ambulance, rescue, or first response
service, or when the member has used the blue or white light beyond
the scope of its authorized use. A person issued an authorization
under subsection 3, paragraph “b”, shall return the authorization
to the fire chief upon expiration or upon a determination by the fire
chief or the department that the authorization should be revoked.
5. When used. The certificate of authorization shall be
carried at all times with the certificate of registration of the
authorized vehicle and the operator of the vehicle shall not
illuminate the blue or white light except in any of the following
a. When the member is en route to the scene of a fire or is
responding to an emergency in the line of duty requiring the services
of the member.
b. When the authorized vehicle is transporting a person
requiring emergency care.
c. When the authorized vehicle is at the scene of an
d. The use of the blue or white light in or on a private
motor vehicle shall be for identification purposes only.
6. Amber flashing light. A farm tractor, farm tractor with
towed equipment, self-propelled implement of husbandry, road
construction or maintenance vehicle, road grader, or other vehicle
principally designed for use off the highway which, when operated on
a primary or secondary road, is operated at a speed of thirty-five
miles an hour or less, shall be equipped with and display an amber
flashing light visible from the rear at any time from sunset to
sunrise. If the amber flashing light is obstructed by the towed
equipment, the towed equipment shall also be equipped with and
display an amber flashing light as required under this subsection.
All vehicles specified in this subsection which are manufactured for
sale or sold in this state shall be equipped with an amber flashing
light in accordance with the standards of the American society of
7. Flashing white light. Except as provided in section
321.373, subsection 7, and subsection 2, paragraphs “c” and
“i” of this section, a flashing white light shall only be used on
a vehicle in the following circumstances:
a. On a vehicle owned or exclusively operated by an
ambulance, rescue, or first response service.
b. On a vehicle authorized by the director of public health
when all of the following apply:
(1) The vehicle is owned by a member of an ambulance, rescue, or
first response service.
(2) The request for authorization is made by the member on forms
provided by the Iowa department of public health.
(3) Necessity for authorization is demonstrated in the request.
(4) The head of an ambulance, rescue, or first response service
certifies that the member is in good standing and recommends that the
authorization be granted.
c. On an authorized emergency vehicle.
The Iowa department of public health shall adopt rules to
establish issuance standards, including allowing local emergency
medical service providers to issue certificates of authorization, and
shall adopt rules to establish certificate of authorization