Transmittal - 5/13/2022ERIN MENDENHALL DEPARTMENT of COMMUNITY
Mayor and NEIGHBORHOODS
Blake Thomas
Director
SALT LAKE CITY CORPORATION
451 SOUTH STATE STREET, ROOM 404 WWW.SLC.GOV
P.O. BOX 145486, SALT LAKE CITY, UTAH 84114-5486 TEL 801.535.6230 FAX 801.535.6005
CITY COUNCIL TRANSMITTAL
________________________
Lisa Shaffer, Chief Administrative Officer
Date Received: 5/13/2022
Date sent to Council: 5/13/2022
______________________________________________________________________________
TO:Salt Lake City Council DATE: May 12, 2022
Dan Dugan, Chair
FROM: Blake Thomas, Director, Department of Community & Neighborhoods
__________________________
SUBJECT:Changing SLC’s Prima Facie Speed Limit From 25 mph to 20 mph
STAFF CONTACT:Jon Larsen, Transportation Director, jon.larsen@slcgov.com, 801-535-7146
Dan Bergenthal, Traffic Safety Engineer, dan.bergenthal@slcgov.com, 801-
535-7106
DOCUMENT TYPE:Ordinance
RECOMMENDATION: Pass an ordinance
BUDGET IMPACT:The estimated implementation cost is $100,000
BACKGROUND/DISCUSSION:At the March 1, 2022, Work Session meeting, the City
Council requested the Transportation Division investigate the feasibility of reducing the city’s
prima facie speed limit from 25 mph to 20 mph. This transmittal is our response to that request.
The Salt Lake City Transportation Division is committed to providing a safe and efficient multi-
modal transportation system for the movement of people and goods. We support the goals of the
Vision Zero and Zero Fatalities programs. We believe the only acceptable goal for traffic
fatalities and serious injuries in our city is zero. We believe that death and injury on our city
streets is preventable and acknowledge the importance of street design in mitigating speed and
the frequency and severity of collisions.
The prima facie speed limit is the default speed limit on all streets, unless otherwise posted.
Since this speed limit is established by city ordinance, the City Council has the authority to
change it. The change would apply to all streets without posted speed limits and local streets
signed at 25 mph. The affected streets comprise approximately 420 miles or 70% of city-owned
public roadways. See the attached files for Maps 1, 2 & 3. Please view these maps on a computer
to allow for zooming in. A sampling of other cities that have recently reduced residential speed
limits from 25 to 20 mph include Seattle, WA; Portland, OR; Eugene OR; Denver, CO; Boulder,
CO; Minneapolis, MN; and St. Paul, MN.
Changing the prima facie speed limit should be based upon solid data. The following questions
will be addressed: How does speed impact our streets? What will be the cost of changing the
prima facie speed limit?
How Speed Impacts Our Streets
Over the last couple of decades, Salt Lake City has seen an ever-increasing boom in housing
development, bringing additional residents to the city each year. In addition, with ongoing
expansions to our pedestrian and bicycling infrastructure, and the relatively recent introduction
of SLC GREENbike bikeshare and electric scooter sharing, our transportation infrastructure is
serving an increasing number of bicyclists and pedestrians, also referred to as vulnerable road
users. We expect this trend of increasing numbers of vulnerable road users to continue into the
foreseeable future.
While increasing non-motorized and transit trips improves the efficiency of our transportation
network by reducing the numbers of motorized vehicles, studies demonstrate that the negative
effects of higher driving speeds persist. In 2019, the National Highway Transportation Safety
Administration created a list of the negative consequences of speeding (https://www.nhtsa.gov/
risky- driving/speeding#:~:text=Increased%20stopping%20distance%20after%20the,Increased
%20fuel%20consumption%2Fcost.). Stating the opposite of those consequences demonstrates
the positive effects of driving slower:
x Lower potential for loss of vehicle control;
x Increased effectiveness of occupant protection equipment;
x Shorter stopping distance after the driver perceives a danger;
x Lower degree of crash severity leading to less severe injuries;
x Lower economic implications of a speed-related crash; and
x Decreased fuel consumption/cost.
Annually, more than 6,000 collisions occur on Salt Lake City streets. Only about 4 percent of
these crashes involve pedestrians and bicyclists, yet these two modes make up more than 46
percent of fatalities in our city. This is a cause for great concern. The main reason for the high
percentage of fatalities with vulnerable road users is that the forces involved in a crash are
applied directly to the human body. In contrast, occupants of enclosed vehicles are surrounded
by metal structures that are engineered to absorb crash forces, minimizing the forces transferred
to vehicle occupants.
As vehicle speeds increase, so do the severity of injuries. Kinetic energy increases exponentially
with velocity [Kinetic Energy=(1/2)*(Mass)*(Velocity)^2]. This means the kinetic energy/force
of a vehicle, traveling at 25 mph is 56% greater than an identical vehicle traveling at 20 mph,
even though the vehicle is only traveling 25% faster. This is especially an issue for vulnerable
road users. The following images display data from a widely referenced 2011 study by the AAA
Foundation for Auto Safety in the United States: Impact Speed and a Pedestrian’s Risk of Severe
Injury or Death Technical Report, Washington, D.C. (chrome-extension://efaidnbmnnnibpcajpcg
lclefindmkaj/viewer.html?pdfurl=https%3A%2F%2Faaafoundation.org%2Fwp-content%2Fuplo
ads%2F2018%2F02%2F2011PedestrianRiskVsSpeedReport.pdf&clen=1337768&chunk=true).
The images provide context for how speed impacts the risk of death for pedestrians involved in
vehicle crashes.
Image Source: United States Department of Transportation Pedestrian Safety Action Plan, 2020
(https://highways.dot.gov/sites/fhwa.dot.gov/files/2020-11/FHWA_PedSafety_ActionPlan_Nov2020.pdf).
According to the AAA study, the average risk of death for a pedestrian hit by a vehicle traveling
at 20 mph is 7%, which rises to 12% at 25 mph, an increase in the risk of death of 71%. In
regards to severe injury, a pedestrian hit by a vehicle traveling at 20 mph is 17%, which rises to
30% at 25 mph, a 76% increase in the risk of severe injury. See figure 1 below. The study also
concludes that the risk of death at every speed is even higher for older pedestrians and
pedestrians hit by trucks and other large vehicles. In addition, crashes are more likely to occur at
high speeds as opposed to lower speeds and, when they do occur, high speed crashes are more
likely to be deadly. As a result, the evidence shows that small reductions in speed result in large
safety gains.
Source: Tefft, B.C. (2011). Impact Speed and a Pedestrian’s Risk of Severe Injury or Death (Technical Report),
Washington, D.C.: AAA Foundation for Traffic Safety. https://aaafoundation.org/wp-
content/uploads/2018/02/2011PedestrianRiskVsSpeedReport.pdf
Based upon SLC crash data for 2015-2019, 223 out of 1336 (17%) of the total crashes involving
pedestrians and bicyclists occurred on the streets that would be impacted by a change in the
prima facie speed limit. This included 3 out of 28 (11%) of the total pedestrian and bicyclist
fatalities and 21 out of 122 (17%) of the total pedestrian and bicyclist severe injury crashes that
occurred during those years.
Moving beyond crash data, there is the element of neighborhood livability associated with
vehicle speeds. The Transportation Division frequently receives complaints from residents
claiming that most drivers are speeding on their streets. The speeding makes them feel
uncomfortable walking, bicycling, and allowing their children to play outdoors. When studies are
conducted, the results generally reveal that most traffic is traveling within a few mph of the
posted or prima facie speed limit. What appears to be happening is that residents either perceive
25 mph to be “too fast” or “too dangerous,” or their thoughts are consumed by the few vehicles
that infrequently travel at higher speeds (over 30 mph).
In January 2018, Portland City Council approved an ordinance reducing the speed limit on all
residential streets from 25 mph to 20 mph. In October 2020, a study was completed by Portland
State University (https://trec.pdx.edu/research/project/1467/Effect_of_Residential_Street_Speed
_ Limit_Reduction_from_25_to_20_mi/hr_on_Driving_Speeds_in_Portland,_Oregon) to
determine if there was a change in observed speeds of vehicles following the speed limit
reduction. According to the study: “Overall, the analysis suggests that the reduction of posted
speed limits to 20 mi/hr has resulted in lower observed vehicle speeds and fewer vehicles
traveling at higher speeds (e.g. over 30 mi/hr). It is most noteworthy that the reduction in the
percentage of vehicles faster than 30 mi/hr and 35 mi/hr are larger in magnitude than the other
changes. These changes are more meaningful for the Vision Zero speed reduction efforts, given
the link to crash severity for vulnerable road users.” Based on these results, it’s reasonable to
conclude that reducing the prima facie speed limit in Salt Lake City from 25 to 20 mph will
improve SLC neighborhood livability and safety. Lower observed speeds along with a reduction
in vehicles infrequently traveling at higher speeds (over 30 mph) are exactly what many of our
residents are asking for and what we, as safety professionals, are striving for.
Cost of Changing the Prima Facie Speed Limit
If the decision is made to change the prima facie speed limit, all existing twenty-five mph speed
limit signs on local roads will need to be replaced. Collector roads signed at 25 mph will remain
in place. We also expect the need to install additional signs (number currently unknown) to help
educate the public. The estimated cost is $100K.
The actual updating of the prima facie speed limit would only require a small change to a single
city ordinance, section B of ordinance 12.36.020, which currently states:
B. Twenty Five Miles Per Hour: On all streets and at all places the prima facie speed limit shall
be twenty five (25) miles per hour, except as otherwise provided in subsection A of this section,
or in such other streets or places as otherwise posted or marked as directed by the city
transportation engineer.
In summary, based upon the crash data for 2015-2019, a reduction in the prima facie speed limit
has the potential to affect about 17% of the overall pedestrian and bicyclist crashes which occur
on SLC streets. Lower speeds result in:
x Lower potential for loss of vehicle control;
x Increased effectiveness of occupant protection equipment;
x Shorter stopping distance after the driver perceives a danger;
x Lower degree of crash severity leading to less severe injuries;
x Lower economic implications of a speed-related crash;
x Decreased fuel consumption/cost;
x Increased sense of neighborhood livability.
If the City Council decides to move forward with this change, the Transportation Division
recommends not increasing speed enforcement on neighborhood streets. Rather, a focus should
be made to educate and enforce blatant speeding violations. The education campaign should
focus on the benefits of slower speeds in our neighborhoods. Targeted outreach to minority
communities should also be included in the education campaign to emphasize that the change in
speed limit is intended to improve safety in their communities, not to provide an excuse for
targeted police enforcement.
PUBLIC PROCESS: The Salt Lake City Transportation Advisory Board (TAB) discussed the
idea of lowering the speed limit on residential streets in the city to 20 mph, in each of their
meetings, August-December 2021. On December 16, 2021, the TAB sent a letter to the
Administration and City Council expressing their support for slowing down traffic to make our
neighborhoods safer. In general, TAB members are supportive of lowing residential speeds to 20
mph but are concerned that perhaps the only way for it to succeed would be to couple it with an
effort to change the design of our streets (traffic calming/livable streets).
At the City Council’s March 1, 2022, Work Session, a local community group, Sweet Streets
SLC, made a presentation to the Council requesting a change to the prima facie speed limit, from
25 to 20 mph.
EXHIBITS:
1) Maps 1-3, SLC Streets Impacted by a Change to the Prima Facie Speed Limit
2) December 16, 2022 letter from the Transportation Advisory Board to the Administration and
City Council regarding Neighborhood Traffic Slowing Efforts
3) Legislative Ordinance
4) Clean Ordinance
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SLC Streets Impacted bya Change to the PrimaFacie Speed LimitMap 1 of 3
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Impacted Streets
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SLC Streets Impacted bya Change to the PrimaFacie Speed LimitMap 2 of 3
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Impacted Streets
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SLC Streets Impacted bya Change to the PrimaFacie Speed LimitMap 3 of 3
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Impacted Streets
TRANSPORTATION ADVISORY BOARD
Salt Lake City Transportation Division Office - 349 South 200 East, Suite 150 - P.O. Box 145502
Salt Lake City, Utah 84114-5502
Neighborhood Traffic Slowing Efforts
Dear Mayor Mendenhall and City Council Members,
The Transportation Advisory Board supports every effort to make our neighborhoods safer. Over the last
decade, many neighborhoods in Salt Lake City have made efforts to help slow down traffic in their
communities. Some of these campaigns include the neighborhood pace car program, the “Slow Down 600
North” project, as well as Paint the Pavement projects, and most recently the Sweet Streets SLC “Twenty is
Plenty“ program.
As previously stated in our letter dated September 25, 2020, “The Salt Lake City Transportation Advisory Board
supports prioritizing the safety of vulnerable roadway users above the convenience and level of service of
motor vehicle traffic in Salt Lake City. These include any users of the public right-of-way who are not protected
by a vehicle, such as people walking, bicycling, using mobility devices and scooters; and people sitting,
standing, and dining outdoors.”
Development of the Salt Lake City Street & Intersection Typologies Design Guide and the updates to the
Transportation Master Plan will allow the City to adopt appropriate speed levels for our neighborhoods and
city streets, thus offering more protection to people being outdoors. There are many tools available to use to
make our communities safer, including use of temporary signage, permanent traffic calming, and continuous
educational campaigns.
The safety of all our neighbors is essential. Reducing the motor vehicle speed in all areas will benefit the
quality of life for everyone, especially people that are not using automotive transportation and other vulnerable
users. Implementation of reduced speeds in those locations in the city will benefit the Complete Streets
protocol, as well as assist street and traffic engineers to continue to understand the livability of the roads they
are building. The Board also understands the need of education, engagement, and enforcement for any
expected changes in roadway behavior.
The Transportation Advisory Board encourages the Mayor’s Office and City Council to address neighborhood
and community concerns about residential speeding and efforts to improve safety for Salt Lake City. Each
neighborhood should not feel they must work individually to make their community safer; this is a city-wide
concern. Adoption of a slower speed in neighborhoods program will provide a standard to all who use our
streets, and increase safety as a priority.
Sincerely,
Courtney Reeser, Chair
Transportation Advisory Board
LEGISLATIVE DRAFT
SALT LAKE CITY ORDINANCE 1
No. _____ of 2022 2
3
(An ordinance amending Section 12.36.020 of the Salt Lake City Code 4
Pertaining to the Prima Facie Speed Limit) 5
6
WHEREAS, Chapter 12.36 “Speed Limits” sets forth the speed limits for streets within the 7
Salt Lake City boundaries; and 8
WHEREAS, Section 12.36.020(B) of the Salt Lake City Code currently sets the prima facie 9
speed limit for all streets at twenty-five (25) miles per hour, with some exceptions for school zones 10
and school bus stops; and 11
WHEREAS, the Salt Lake City Transportation Division is committed to providing a safe 12
and efficient transportation system for those travelling within Salt Lake City and further supports 13
the goals of the Vision Zero and Zero Fatalities programs; and 14
WHEREAS, the Transportation Division has presented evidence that a reduction of the 15
prima facie speed limit to twenty (20) miles per hour will likely decrease the frequency of 16
collisions involving motorized vehicles, as well as the severity of outcomes for those involved in 17
collisions, particularly for vulnerable road users such as bicyclists and pedestrians; and 18
WHEREAS, the Salt Lake City Council finds that updates to the current ordinance are 19
necessary to reduce the prima facie speed limit within Salt Lake City from twenty-five (25) miles per 20
hour to twenty (20) miles per hour to promote public safety and welfare. 21
NOW, THEREFORE, be it ordained by the City Council of Salt Lake City, Utah: 22
SECTION 1. Amending Section 12.36.020. Section 12.36.020 of the Salt Lake City Code 23
shall be, and hereby is, amended to read as follows: 24
Where no special hazard exists that requires a lower speed for compliance with section 12.30.010 25
of this chapter, or its successor, the speed of any vehicle in excess of limits specified in this title is 26
prima facie evidence that the speed is not reasonable or prudent and that it is unlawful: 27
28
LEGISLATIVE DRAFT
A. Twenty Miles Per Hour: 29
30
1. Upon meeting or overtaking any school bus which has stopped on the street for the 31
purpose of receiving or discharging any schoolchildren, provided such school bus bears 32
upon the front and rear thereof a plainly visible sign containing the words “school bus” in 33
letters no less than four inches (4”) high which can be removed or covered when the 34
vehicle is not in use as a school bus; 35
36
2. When passing a school building or the grounds thereof, or through a designated school 37
crossing zone during school recess, or while children are going to or leaving school 38
during opening or closing hours; 39
40
3. On all streets and at all places the prima facie speed limit shall be twenty (20) miles per 41
hour, except on such other streets or places as otherwise posted or marked as directed by 42
the city transportation engineer. 43
SECTION 2. Effective Date. This Ordinance shall become effective on the date of its first 44
publication. 45
Passed by the City Council of Salt Lake City, Utah this __ day of ____________, 2022. 46
47
48
CHAIRPERSON 49
ATTEST: 50
51
52
______________________________ 53
CITY RECORDER 54
55
56
Transmitted to Mayor on . 57
Mayor’s Action: _______Approved. _______Vetoed. 58
59
60
61
MAYOR 62
63
64
______________________________ 65
CITY RECORDER 66
67
(SEAL) 68
69
LEGISLATIVE DRAFT
70
Bill No. ________ of 2022. 71
Published: ______________. 72
73
74
SALT LAKE CITY ORDINANCE
No. _____ of 2022
(Ordinance amending Section 12.36.020 of the Salt Lake City Code
Pertaining to the Prima Facie Speed Limit)
WHEREAS, Chapter 12.36 “Speed Limits” sets forth the speed limits for streets within the
Salt Lake City boundaries; and
WHEREAS, Section 12.36.020(B) of the Salt Lake City Code currently sets the prima facie
speed limit for all streets at twenty-five (25) miles per hour, with some exceptions for school zones
and school bus stops; and
WHEREAS, the Salt Lake City Transportation Division is committed to providing a safe
and efficient transportation system for those travelling within Salt Lake City and further supports
the goals of the Vision Zero and Zero Fatalities programs; and
WHEREAS, the Transportation Division has presented evidence that a reduction of the
prima facie speed limit to twenty (20) miles per hour will likely decrease the frequency of
collisions involving motorized vehicles, as well as the severity of outcomes for those involved in
collisions, particularly for vulnerable road users such as bicyclists and pedestrians; and
WHEREAS, the Salt Lake City Council finds that updates to the current ordinance are
necessary to reduce the prima facie speed limit within Salt Lake City from twenty-five (25) miles per
hour to twenty (20) miles per hour to promote public safety and welfare.
NOW, THEREFORE, be it ordained by the City Council of Salt Lake City, Utah:
SECTION 1. Amending Section 12.36.020. Section 12.36.020 of the Salt Lake City Code
shall be, and hereby is, amended to read as follows:
Where no special hazard exists that requires a lower speed for compliance with section 12.30.010
of this chapter, or its successor, the speed of any vehicle in excess of limits specified in this title is
prima facie evidence that the speed is not reasonable or prudent and that it is unlawful:
A. Twenty Miles Per Hour:
1. Upon meeting or overtaking any school bus which has stopped on the street for the
purpose of receiving or discharging any schoolchildren, provided such school bus bears
upon the front and rear thereof a plainly visible sign containing the words “school bus” in
letters no less than four inches (4”) high which can be removed or covered when the
vehicle is not in use as a school bus;
2. When passing a school building or the grounds thereof, or through a designated school
crossing zone during school recess, or while children are going to or leaving school
during opening or closing hours;
3. On all streets and at all places the prima facie speed limit shall be twenty (20) miles per
hour, except on such other streets or places as otherwise posted or marked as directed by
the city transportation engineer.
SECTION 2. Effective Date. This Ordinance shall become effective on the date of its first
publication.
Passed by the City Council of Salt Lake City, Utah this __ day of ____________, 2022.
CHAIRPERSON
ATTEST:
______________________________
CITY RECORDER
Transmitted to Mayor on .
Mayor’s Action: _______Approved. _______Vetoed.
MAYOR
___________________________
CITY RECORDER APPROVED AS TO FORM
(SEAL) Salt Lake City Attorney’s Office
Date: April 21, 2022
Bill No. ________ of 2022
Published: ______________. _______________________________
Sara Montoya, Senior City Attorney