HomeMy WebLinkAboutStaff Report to PC 1-25-08
STAFF REPORT - DRAFT
TO:
Planning Commission
FROM:
Michael D. Franzen, City Planner
DATE: January 25, 2008
PROJECT:
Draft Ordinance “Dynamic Display” Relating to Signs Displaying
Animation or Electronically Changing Images or Messages
INTRODUCTION
On February 20, 2007, the City Council adopted a resolution authorizing a study of signs
displaying animation or electronically changing images or messages. The City’s current
ordinance was developed at a time when “Dynamic Display” or LED signs were not envisioned.
The Council directed City Staff to conduct a study on the effectiveness of the City’s current sign
ordinance and to determine what amendments to the City Code are necessary to effectively
regulate digital signs. Pursuant to the Council’s direction and in order to assist the Planning
Commission and the Council in their own analysis of the issue, City Staff has compiled this
report setting forth the Staff’s findings along with recommended areas of regulation.
HOW DOES THE CITY CURRENTLY REGULATE LED SIGNS?
1.The Eden Prairie City Code (“Code”) states “no illuminated sign which changes in either
color or intensity of light, flashes, scrolls, or is animated shall be permitted.” Motion signs,
defined as “any sign which revolves, rotates, or has any moving parts or message,” are also
prohibited.
2.The Code also requires a sign’s light source to be diffused or directed to eliminate glare and
prevent interference with traffic regulations.
3.The Code prohibits many of the advanced features LED signs are capable of, such as
displaying video, animation, scrolling messages, etc.
4.The Code does not provide the City the ability to regulate other features of LED signs. For
example, the Code’s prohibition against changes in color or intensity of light may be
insufficient to prohibit occasional, instantaneous changes of the sign’s face from one static
display to another.
5. The Code’s regulations with respect to illumination are also insufficient to effectively
regulate LED illumination.
STUDIES
The cities of Bloomington and Minnetonka have performed studies on the subject of digital
advertising. The studies include research of many other cities and court cases throughout the
United States. The studies, which are attached to this report, are:
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City of Bloomington, “Study Advanced Technology Outdoor Advertising,” October 9, 2006.
SRF Consulting Group Report, “’Dynamic’ Signage: Research Related to Driver Distraction
and Ordinance Recommendations,” prepared for the City of Minnetonka, June 7, 2007.
Minnetonka Planning Commission Staff Report, June 14, 2007.
Minnetonka’s and Bloomington’s relevant code sections are also attached.
1.The studies find that digital signs can distract drivers, which can potentially lead to an
increase in traffic accidents.
2.The studies do not definitively prove a causal relationship between digital advertising and
roadway accidents because it is impossible to simulate actual driving conditions in a
controlled environment.
3.The studies show a sufficient correlation between digital signs and driver distraction to
support the City’s ability to regulate digital signage for the general health, welfare and safety
of its citizens.
Staff has reviewed the studies, and the sources cited therein, and concur with their findings.
Engineering staff has reviewed the SRF Consulting Group Report, and concur with the findings
and recommendations. The Eden Prairie Engineering Division concurs that there is a
relationship between dynamic signage and increased driver distraction and that dynamic signs
should be viewed as a public safety issue for the City. (See attached Memo from the Traffic
Engineer).
LEGAL BASIS FOR REGULATION
Cities may regulate commercial speech as long as the regulation is narrowly tailored to support
an important governmental interest. Courts have ruled that ordinances restricting flashing and
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animated signs are constitutional. A city may regulate signage in order to protect the health,
safety, and public welfare of its citizens. This right includes controlling signage that can
potentially distract drivers and increase the likelihood of traffic accidents.
Courts have determined that time and temperature displays are an exception to a city’s ability to
regulate dynamic signs. Furthermore, many cities exclude traffic information and warnings,
along with state and federal information on dynamic signs from sign ordinances.
STAFF RECOMMENDATIONS
City Staff recommends that the Planning Commission and Council consider the various areas of
regulation set forth below and provide City Staff direction on what to include in the City’s new
sign ordinance. Staff recommends the following changes apply to all freestanding signs,
including billboards.
1.Create a Definition of “Dynamic Displays.”
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See Bloomington Study, pgs. 1-3.
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Staff recommends adding a definition of “Dynamic Displays” to the Code. Dynamic
Displays should include any display that is capable of changing messages aside from
physical changing the display of the sign. Dynamic Displays include tri-vision signs, all
forms of digital signs, and any other sign that is capable of changing its message without
physical intervention. Minnetonka’s definition is provided below as an example.
Dynamic display
” - any characteristics of a sign that appear to
have movement or that appear to change, caused by any method
other than physically removing and replacing the sign or its
components, whether the apparent movement or change is in the
display, the sign structure itself, or any other component of the
sign. This includes a display that incorporates a technology or
method allowing the sign face to change the image without having
to physically or mechanically replace the sign face or its
components. This also includes any rotating, revolving, moving,
flashing, blinking, or animated display and any display that
incorporates rotating panels, LED lights manipulated through
digital input, “digital ink” or any other method or technology that
allows the sign face to present a series of images or displays.
Staff recommends removing the portions of the Code banning signs that change in color
or intensity of light, flash, scroll, or contain animation or motion, and replacing them with
a general prohibition against Dynamic Displays. The Code may then list certain
exceptions under which Dynamic Displays will be permitted.
This approach is beneficial for two reasons. First, it addresses LED technology while at
the same time allowing the Code the ability to adapt to new technology. Second, it
clarifies a point of confusion by removing references to flashing, scrolling, or animated
signs. Overall, creating the Dynamic Display definition would give the City a valuable
tool to effectively regulate all forms of dynamic signage within the City.
2. Dynamic Displays should be static, with changes to the sign’s faces permitted once
every 24 hours.
Studies show that display changes and other unexpected stimuli can be extremely
distracting to drivers. For example, one study concluded that drivers glance at dynamic
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signs twice as often and for longer periods than at non-dynamic signs. This can interfere
with a driver’s reaction time when stopping suddenly or in complex driving conditions.
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Drivers also spend more time looking at unfamiliar signs than familiar ones. Dynamic
displays change their message, which will increase the number of unfamiliar signs a
driver sees.
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SRF Consulting Report, p. A9.
3
SRF Consulting Report, p. A7.
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Furthermore, studies have shown that drivers may watch a sign waiting for the next
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change to occur. Humans have a natural desire to complete one task before beginning
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another, called the “Zeigarnik effect.” Drivers tend to watch signs with changing images
more closely, waiting for the change to occur.
Based upon these studies’ findings, Staff recommends permitting a sign display to change
no more than once every 24 hours. Although the Staff’s proposed display period is
longer than many other municipalities in the area (Minnetonka’s and Bloomington’s are
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both every 20 minutes), it falls within the outer range of other cities studied. Staff also
recommends display changes should be instantaneous without any special effects, and
that animated signs, and signs that depict motion of any kind, be prohibited entirely.
One final issue to consider is whether the City would like to make an exception for time
and temperature signs. Courts have upheld exceptions allowing time and temperature
signs. Minnetonka and Bloomington make an exception for time and temperature signs.
The draft ordinance states:
Duration of Image
“. A Dynamic Display’s image, or any portion thereof, may not
change more often than once every 24 hours, except one for which changes are necessary
to correct hour-and-minute, date, or temperature information. A display of time, date, or
temperature must remain for at least 24 hours before changing to a different display, but
the time, date, or temperature information itself may change no more often than once
every three seconds.”
3. Define Brightness Levels
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The brightness of any sign raises safety concerns. “Disability glare” occurs when a
driver is exposed to light so bright that it temporarily impairs their vision. “Discomfort
glare” occurs when the light is bright enough to cause distraction but does not impair
vision. Both can be dangerous and increase the potential for accidents.
The brightness of all signs should be regulated by the City’s ordinance. Dynamic signs,
especially those comprised of LED lights, can give off significantly more light than
traditional signs. Staff recommends that no sign should be bright enough to impair the
vision of a driver with normal eyesight at any time during a continuous 24 hour period.
Dynamic signs should have the same appearance as traditional signage with normal light
configurations.
Bloomington and Minnetonka each follow a different method of regulating brightness.
Bloomington permits a maximum illumination of 5,000 nits during daylight hours
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Minnetonka Planning Commission Staff Report, p. 2.
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Bloomington Study, p. 4; SRF Consulting Report, p. A10; Minnetonka Planning Commission Staff Report, p. 2.
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SRF Consulting Report, p. A23.
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SRF Consulting Report, p. A18-A19.
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and 500 nits between sunset and sunrise. A nit is the measure of light emanating from
the sign with respect to the size of the sign. It is the total amount of light emitted divided
by the surface of the sign area or candelas per square meter. Light can be factory set
using a spectral photometer.
If the City follows this method, the City should determine the maximum nits for day and
night, and whether the regulations will vary between different districts that have diverse
signage setbacks.
Minnetonka has determined that it is too difficult to accurately measure nits. Instead,
Minnetonka’s ordinance contains three general prohibitions:
1) No sign may be brighter than is necessary for clear and adequate visibility.
2) No sign may be of such intensity or brilliance as to impair the vision of a motor
vehicle driver with average eyesight or otherwise interfere with the driver’s operation of
a motor vehicle.
3) No sign may be of such intensity or brilliance that it interferes with the effectiveness
of an official traffic sign, device or signal.
These general prohibitions permit Minnetonka to determine if a sign is too bright without
measuring nits. The ordinance also includes an appeals process whereby the sign owner
may appeal the city’s determination. The City should consider which method of
regulating brightness – Bloomington’s or Minnetonka’s – best meets the City’s
requirements.
With respect to brightness, Staff recommends:
1.Establish a measurable brightness level. (the Nit)
2.Require signs to be equipped with a mechanism to control the sign’s brightness.
3.Establish the city’s authority to disable or turnoff a sign that malfunctions in a
manner that creates excessive glare or brightness.
4.Establish a requirement for a written certification from the sign manufacturer that
the sign has been preset to limit the maximum light intensity.
5.Require sign owners to provide an accurate field method of insuring that
maximum light levels are not exceeded.
4. Sign Maintenance
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Studies have shown that a poorly maintained dynamic sign distracts drivers. For
example, if a malfunctioning sign becomes difficult to read or acts in some other
unexpected fashion, drivers are more likely to spend more time looking at the sign. A
malfunctioning LED sign can become excessively bright. Minnetonka’s ordinance
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Bloomington’s Study, p. 5.
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requires dynamic signs to be equipped with a mechanism that will freeze the sign in one
position if a malfunction occurs. The signs must also be equipped with a means to
immediately turn off the display if it malfunctions or does not comply with the
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ordinance’s standards. Staff recommends including similar regulations in the Eden
Prairie’s ordinance.
5. Locations
The Code already restricts the size and location of various types of signs by zoning
district. Staff recommends that the location of dynamic displays be regulated as follows:
1.Permit LED signs in the Commercial Regional, Community Commercial,
Neighborhood Commercial, Commercial Regional Service, Office, Town Center
and Industrial Districts.
2.Prohibit LED signs in all residential districts, public and golf course districts.
SUMMARY OF STAFF RECOMMENDATIONS
1.Create new “Dynamic Display” definition in City Code.
2.Permit dynamic displays to change instantaneously once every 24 hours.
3.Establish a measurable brightness level
4.Prohibit dynamic displays from using video, animation, or any appearance of movement.
5.Establish a requirement for a written certification from the sign manufacturer that the
sign has been preset to limit the maximum light intensity.
6.Establish LED brightness standards that require signs to be equipped with a mechanism
to control the sign’s brightness.
7.Require dynamic display owners to provide an accurate field method of insuring that
maximum light levels are not exceeded.
8.Establish the city’s authority to disable or turnoff a sign that malfunctions in a manner
that creates excessive glare or brightness.
9.Permit dynamic displays in the Commercial Regional, Commercial Regional Service,
Community Commercial, Neighborhood Commercial, Office, Town Center and
Industrial Districts.
10.Prohibit dynamic displays in all residential districts, public and golf course districts.
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Minnetonka Planning Commission Staff Report, p. 6
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