04 21 2026 CC Work Session Packet.pdf
CITY OF MENDOTA HEIGHTS
CITY COUNCIL WORK SESSION MEETING AGENDA
April 21, 2026 at 4:30 PM
Mendota Heights City Hall, 1101 Victoria Curve, Mendota Heights
1. Call to Order
2. Discussion
a. Radar Feedback Speed Limit Signs
b. Performance Measure Report
c. Independence Day/250th Anniversary Event Update
3. Adjourn
Alternative formats or auxiliary aids are available to individuals with disabilities upon request.
Please contact City Hall at 651-452-1850 or by emailing cityhall@mendotaheightsmn.gov.
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2.a
City Council Work Session Memo
MEETING DATE: April 21, 2026
TO: Mayor, City Council and City Administrator
FROM: Lucas Ritchie, Assistant City Engineer
SUBJECT: Radar Feedback Speed Limit Signs
ACTION REQUEST:
Provide staff direction on the City’s use of radar feedback speed limit signs as a traffic
management tool.
BACKGROUND:
Radar feedback speed limit signs are commonly used to communicate vehicle speeds and
reinforce posted speed limits. The City of Mendota Heights has installed seven of these signs
in recent years in response to neighborhood concerns about excessive speeding.
While radar feedback signs are widely used, some research and practitioners have noted
potential limitations, including reduced effectiveness over time as drivers become accustomed
to the signs, and inconsistent long-term speed reduction impacts.
City staff have identified twelve additional priority locations for new radar feedback signs
along Municipal State Aid (MSA) routes. Proposed locations include Emerson Avenue near
Somerset Elementary School, Lake Drive near Saint Thomas Academy and Visitation School,
Huber Drive and Mendota Heights Road near Friendly Hills Middle School, Victoria Road, and
Wachtler Avenue. These routes often connect County Roads and State Highways where higher
posted speeds can carry over into local streets, contributing to elevated traffic speeds.
Staff have continued to receive resident concerns regarding speeding on these corridors, and
the availability of MSA funding provides an opportunity to implement these measures at no
cost to the City’s general fund.
The new signs would provide drivers with additional speed limit reminders while also
collecting traffic data that can be analyzed to identify long-term speeding patterns. This
information can help staff evaluate future traffic calming measures and potential speed limit
changes during roadway reconstruction projects.
ATTACHMENTS:
1. Proposed Radar Feedback Locations
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2.Long-Term Effectiveness Study
3.Dynamic Speed Display Feedback Signs Article
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Long-Term Effectiveness of Dynamic Speed Monitoring Displays
(DSMD) for Speed Management at Speed Limit Transitions
Wayne Sandberg, Ted Schoenecker, Kristi Sebastian, and Dan Soler
Abstract. Speeding continues to be a significant safety issue on today’s roadways. Studies have
demonstrated that increased compliance with properly established speed limits reduces crash
incidence and severity. One of the outcomes of Intelligent Transportation System (ITS)
technology is the development of practical tools to enable the traffic engineer to more effectively
manage speed on their roadway system. The Dynamic Speed Monitoring Display (DSMD) sign
is one such tool. These signs measure the speed of the approaching vehicles and then feed this
information back to the driver in real time via a dynamic message display. Portable DSMD
signs (a.k.a. speed trailers) have been shown to be an effective engineering countermeasure for
short-term speed control. However, experience has shown that as soon as the device is removed,
speeds soon return to their previous levels.
This paper reports the results of a long-term evaluation of DSMD signs at speed reduction
transition zones, which are those locations where the speed limit changes from a higher speed to
a lower speed. The study was specifically targeted at locations were a rural highway transitions
into an urbanized area. The study found a statistically significant decrease in overall vehicle
speed immediately after the installation of the DSMD signs. The average speed reduction across
all of the study sites was seven mph and it was found that these speed reductions were
maintained over the course of the one year duration of the study. DSMD signs were shown to be
effective long-term for speed management at speed transitions zones.
INTRODUCTION
Drivers who exceed the posted speed limits have become a major concern for transportation
agencies, cities and communities. These drivers, whether intentionally or not, place themselves
and others in danger as well as reduce the overall quality of life for nearby residents and
neighbors. Recent research suggests that safety can be improved by increased driver
conformance to the posted speed (1).
The challenge agencies face is how to improve conformance with the posted speed limit. Many
speeding drivers are local residents who are comfortable with the area. These motorists, many
times, unconsciously speed through their own neighborhoods. The static speed limit sign alone,
while effective in many areas, does not always create the conformance that is desired.
Generally, the concern related to speed conformance manifests itself at locations where the
regulatory speed limit changes. These locations, generally involving changes from a higher
speed (e.g., 50 mph) to a lower speed (e.g., 35 mph), are often related to a change in the
characteristics of the roadway environment. For example, a two-lane highway may have a speed
limit of 55 miles per hour. As the same highway enters into a more residential area, the speed
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limit may drop to 35 miles per hour. Although the amount of traffic is constant, the presence of
homes, businesses, and pedestrians necessitates the need for a lower travel speed.
Historically engineers have looked to enforcement tools, either active or passive, as a solution to
speeding. Active enforcement entails police vehicles patrolling the roadway writing tickets to
speeding motorists. Passive enforcement relies on the motorists to correct their own driving
behavior. An example of this is the use of a portable speed trailer placed along a roadway. In
both cases, observations have show that once the police vehicle is out of sight or the speed trailer
is removed, vehicle speeds return to their previous levels (2, 3).
Engineers have had a limited toolbox when it comes to improving speed limit conformance.
Additionally, ideas that once worked, soon become obsolete or lose their effectiveness. Traffic
characteristics of roads can change with time and development. Many locations that were once
outlying low volume rural roads are seeing significant increases in traffic volume and vehicle
speeds as urban areas grow. Conventional tools included the installation of signs and/or
pavement markings and the use of high visibility sheeting to increase sign conspicuity. Even
with these efforts, many drivers will still exceed posted speed limits.
One new tool that addresses speed issues by combining engineering and education is the
Dynamic Speed Monitoring Display (DSMD) sign (Figure 1). DSMD signs are a practical
outcome of advances in ITS technology. These traffic control devices are self contained ITS
systems that measure the speed of an approaching vehicle using a radar embedded in the sign,
then feeding this information back to the driver in real time via a dynamic message display. The
DSMD sign encourages the driver to act more safely by adjusting their speed to come into
compliance with the posted speed limit. The DSMD sign, permanently installed in conjunction
with a standard static regulatory speed limit sign (MUTCD R2-1), provides information to the
motorist of the speed at which they should be driving with the static sign and the speed at which
they are driving with the DSMD sign – a total package of information that is easy for the driver
to comprehend without distraction.
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Figure 1 – Dynamic Speed Monitoring Display (DSMD) Assembly used in this study
THE STUDY
Studies have been conducted on the effectiveness of permanently installed DSMD signs in a
number of applications, particularly for speed management in school zones and urban traffic
calming (4, 5). The purpose of this paper is to report on the results of a long-term evaluation of
these devices at speed reduction transition zones, which are those locations where the speed limit
changes (transitions) from a higher speed to a lower speed. The study was specifically targeted
at locations were a rural highway transitions into an urbanized area. An important objective of
this study was to assess the long-term effectiveness of permanently installed DSMD signs. It is
well documented that DSMD signs are an effective speed management tool, but the majority of
the studies have only evaluated short term effectiveness – typically over the course of a few days
to a few months (6, 7). Concerns have been raised that DSMD signs may lose their
effectiveness over time as drivers become accustomed to seeing them on a regular basis.
STUDY DESIGN
The study was conducted as a Before-and-After with Control site design (8). This format was
chosen due to the long-term nature of the study. Use of a control (untreated) site chosen
randomly from the population of possible treatment sites overcomes the drawbacks associated
with simple Before-and-After studies. A control site provides information on both seasonal and
long-term variation in traffic. The criteria used to identify the test sites were:
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1) Located on county controlled roads within Washington County or Dakota County,
Minnesota.
2) Transition from a rural high speed highway to an urbanized area.
3) Reduction in posted speed limit of 10 mph or greater at the transition.
4) Existing history of speed related safety concerns.
5) No other engineering measures planned at the site for at least 12 months.
Five locations were chosen from among a number of potential locations meeting the criteria.
Four locations were designated as experimental sites and one as the control site (Table 1). The
three sites in Washington County (2 experimental, 1 comparison) were speed reductions from 50
to 30 mph, 55 to 40 mph and 55 to 30 mph (Control) on rural two lane highways as they entered
urban areas. The Dakota County locations were located along a single stretch of highway where
there were two successive speed transitions. The first transition was from 55 mph to 45 mph
followed by a second transition 0.7 miles downstream from 45 mph to 35 mph. All the locations
in this study were two lane roads. At each of the experimental locations, the existing R2-1 sign
indicating the reduced speed was replaced with an assembly consisting of a DSMD sign mounted
directly below the speed limit sign (see Figure 1). No changes were made at the Control site.
Table 1- Study Test Sites
Location Initial Speed
Limit
(mph)
Reduced Speed
Limit at
Transition
(mph)
Average Daily
Traffic
(ADT)
Date DSMD
Signs
Installed
Experimental Sites
Hugo (CSAH 8)
Washington County 50 30 12,000 Nov 2004
Bailey (CSAH 18)
Washington County 55 40 4,000 Nov 2004
Hastings #1 (CSAH 46 )
Dakota County 55 45 11,000 May 2005
Hastings #2 (CSAH 46 )
Dakota County 45 35 11,000 May 2005
Control site (untreated)
Stonebridge (CSAH 5)
Washington County 55 30 5,000 --
Note: CSAH = County State Aid Highway
Dynamic Speed Monitoring Display Assembly
The DSMD signs used in this study were 3M Driver Feedback Signs operating on AC power.
These signs conform to the requirements of the MUTCD for changeable message signs that
display to approaching drivers the speed at which they are traveling (9). The dimensions of the
speed limit sign and the DSMD sign were both 36 inch x 48 inch. This sign size is
recommended in the MUTCD for use on higher speed rural highways. The signs used in the
study utilize a NEMA TS4 Hybrid dynamic message display that combines Fluorescent Yellow-
Green retroreflective pixels with integrated high-output 590 nm InGaAIP LEDs (10). Hybrid
displays were chosen to maximize sign target value and legibility under all conditions – day,
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night and inclement weather. The frame surrounding the hybrid display as well as the face of the
R2-1 Speed Limit sign was White ASTM Type IX retroreflective sheeting.
The DSMD used K-band radar embedded within the sign to measure the speed of the
approaching vehicles. The signs were programmed to display the speed to the motorist in real
time and to flash until that motorist slowed down to at or below the posted speed limit at the
transition point. The DSMD signs were programmed with minimum and maximum speed
display cut-off limits to discourage reckless drivers attempting to see how fast they could go.
These signs also have the capability for vehicle speed data collection; however, this feature was
not used for this study.
Data Collection
Limited data for analysis is a common problem in field research. Sufficient data must be
collected in order to allow a thorough analysis of the results of the experiment. Vehicle speed
and traffic volume data was collected at two positions at each location. The first position,
denoted the Advance site, was one-third to one-half mile upstream of the speed limit reduction.
The position of the Advance site was chosen such that the DSMD was inconspicuous in the
distance. The Advance sites also function as comparison sites since speeds at these locations
should not be influenced by the DSMD. The second set of data was collected adjacent to the
DSMD sign, which is the point where the reduced speed limit officially begins and where the
driver should now be traveling at the new lower speed.
The plan called for the signs to be installed at the same time at all of the sites. Data collection
was then to be conducted at all sites simultaneously at defined intervals over the course of one
year. These intervals were nominally:
• Before installation of the DSMD sign
• One week after
• Two months after
• Seven months after
• One year after
The original plan was adhered to at the Washington County sites (2 experimental sites and the
control site) with only a few modifications due to the Minnesota weather. These signs were
installed in November 2004. Installation of the DSMD assemblies at the test location in Dakota
County that comprised of two consecutive speed transitions were delayed until May 2005 due to
difficulty installing power for the signs during the winter. Due to logistical problems One Week
After data was not collected for the Dakota County locations.
This study used commercial pneumatic tube traffic data recorders with electronic data collection
to measure vehicle speed and volume. Vehicle speeds were binned in 1 mph increments at 15-
minute intervals. All measurements were taken mid-week for 48 to 72 consecutive hours
simultaneously at both the Advance and DSMD sign positions. Simultaneous data collection
provided a counter balance for day–to–day variability.
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STUDY RESULTS
In any long-term study, there is natural variation in traffic volume and speed. In order to draw
conclusions on the persistent effectiveness of the DSMD signs, a review should be made to
check for potential external influences other than the DSMD sign. Table 2 presents the average
directional daily traffic volume through each of the sites during the measurement periods. The
corresponding Average Daily Traffic (ADT) is approximately twice the volumes listed in the
table. With one exception, the data shows the 24-hour average traffic to be relatively stable. The
majority of the test sites showed only a two to four percent variation in traffic volume over time
with no distinct trend. However, at the Bailey site, there is a consistent increase in volume over
the course of the study, which is mainly due to completion of a nearby major construction
project.
Table 2 - Average Directional Daily (24-hour) Traffic Volume through the Study sites
Location Before 2 Months 7 months 1 year
Hugo Advance 6214 5614 6560 5899
Hugo DSMD 6115 5527 6385 6197
Bailey Advance 2107 2440 3506 2720
Bailey DSMD 2193 2450 3526 2788
Hastings Advance 5343 5342 4914 5507
Hastings #1 DSMD 5863 5747 --1 5924
Hastings #2 DSMD 5133 4940 4706 5281
Stonebridge Advance 2568 --1 2804 --2
Stonebridge Control 2511 2223 2754 --2
Notes: 1Data lost due to equipment malfunction; 2Data not collected due to installation of a DSMD sign at this site
The speed data was compiled, reduced and analyzed using both Microsoft ® Office Excel 2003
and Minitab ® Release 14.13 statistical software. A number of descriptive statistics were
generated as a function of time and location, including:
• Average speed
• 50th (median), 85th and 95th percentile speeds
• 10-mph Pace
The 24-hour speed results for the control and study sites are summarized in Tables 3, 4 and 5.
Statistical analyses were run on the data comparing changes in vehicle speed distributions as a
function of time period and location. Significance testing included an analysis of Variance, Z-
test, t-test and Odds Ratio. All statistical measures showed highly significant associations (alpha
< 0.01) between the presence of a DSMD sign and speed reductions within the transition zone.
The study sites with the DSMDs experienced reductions in the 50th, 85th and 95th percentile
speeds averaging 6.3, 6.9 and 7.0 mph, respectively. The 10-mph Pace speeds also decreased at
all the DSMD locations. These results indicate the DSMD shifted the entire speed distribution at
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the transition zone. At the Advance sites and the Control site, the corresponding speeds were
either flat or increased slightly over the course of the research.
The data at the Stonebridge Control site was only collected through 7 months. Due to the need
to address the existing speed related safety concerns at this location and based on the positive
results of this study up to that point in time, Washington County installed a DSMD sign
assembly just prior to the One Year After data collection period.
Table 3 - Results for the Control (untreated) Site
Mean
Speed
(mph)
Standard
Deviatio
n (σ)
Sample
size
50th
Percentile
Speed
85th
Percentile
Speed
95th
Percentile
Speed
10 mph
Pace
(mph)
Stonebridge Advance (55 mph)
Before 52.6 6.6 7881 53 59 62 48-57
1 week 50.6 6.4 7547 51 56 60 46-55
2 months -- -- -- -- -- -- --
7 months 53.5 7.0 8416 54 59 63 51-60
Stonebridge Control (30 mph)
Before 40.2 6.8 7739 40 45 49 36-45
1 week 41.7 7.0 7397 42 48 52 36-45
2 months 39.2 6.7 5712 39 45 49 36-45
7 months 40.0 6.7 8290 40 45 49 36-45
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Table 4 - Results for the Washington County Study Sites
Mean
Speed
(mph)
Standard
Deviatio
n (σ)
Sample
size
50th
Percentile
Speed
85th
Percentile
Speed
95th
Percentile
Speed
10 mph
Pace
(mph)
Hugo Advance (50 mph)
Before 51.8 7.5 18403 52 58 60 46-55
1 week 54.0 7.5 17699 54 60 64 51-60
2 months 52.3 7.4 16979 53 59 62 46-55
7 months 52.8 7.9 19203 53 59 63 51-60
1 year 51.2 7.5 15199 51 57 60 46-55
Hugo DSMD (30 mph)
Before 44.2 7.7 18085 44 50 54 41-50
1 week 37.1 8.4 17336 36 44 49 31-40
2 months 36.1 8.1 16613 35 42 47 31-40
7 months 37.0 8.5 18678 36 43 49 31-40
1 year 36.0 6.9 16025 36 43 45 31-40
Bailey Advance (55 mph)
Before 50.6 6.4 6201 51 56 59 46-55
1 week 51.0 14.9 6360 55 63 67 51-60
2 months 51.3 6.9 7254 51 58 61 46-55
7 months 50.4 7.6 10451 51 57 60 46-55
1 year 50.1 7.0 5645 50 57 60 46-55
Bailey DSMD (40 mph)
Before 50.9 7.2 6305 51 58 63 46-55
1 week 44.6 7.9 6048 44 50 57 41-50
2 months 42.3 5.4 7253 42 47 50 36-45
7 months 45.7 6.4 10521 45 51 55 41-50
1 year 43.3 6.4 5433 43 49 53 36-45
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Table 5 - Results for the Dakota County Study Sites
Mean
Speed
(mph)
Standard
Deviatio
n (σ)
Sample
size
50th
Percentile
Speed
85th
Percentile
Speed
95th
Percentile
Speed
10 mph
Pace
(mph)
Hastings Advance (55 mph)
Before 52.5 7.3 9782 53 59 62 46-55
2 months 49.8 7.4 10019 50 55 60 46-55
7 months 49.6 7.2 8995 49 55 60 46-55
1 year 50.2 7.9 10181 51 56 60 46-55
Hastings #1 (45 mph)
Before 52.1 7.4 10667 52 58 62 46-55
2 months 47.1 6.9 10812 47 52 57 41-50
7 months -- -- -- -- -- -- --
1 year 45.9 7.9 10984 47 52 55 41-50
Hastings #2 (35 mph)
Before 39.0 8.6 9250 39 45 50 36-45
2 months 36.0 7.9 9318 36 40 45 31-40
7 months 36.0 7.9 9318 36 40 45 31-40
1 year 34.5 6.8 9658 36 40 44 31-41
DISCUSSION
There are two basic questions that must be answered in order to determine whether a new traffic
control device will be a useful and reliable addition to the engineer’s speed management toolbox:
1) In what applications is it effective?
2) Does the device have a persistent effect on driver speed behavior?
The objectives of this study were to address both of these questions. The results of this study
were very consistent across all test sites as demonstrated by the data in Tables 3-5. This
discussion will use primarily the results from the Hugo locations in Washington County to
illustrate the answers to these questions.
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Effectiveness for the Application
Recent studies have shown DSMD signs to be effective for speed control at school zones and
urban traffic calming. This project evaluated their effectiveness at speed transition zones,
particularly where the DSMD sign is used in combination with the regulatory Speed Limit sign.
The results of the study show the DSMD sign is an effective tool for reducing speed and
increasing compliance at speed transition areas. Figure 2 illustrates the change in 85th percentile
speed for the Hugo test site, the Stonebridge control site, and the average speed reduction over
all the DSMD locations.
Figure 2 – Change in 85th Percentile Speed as a Function of Time period.
-10.0
-8.0
-6.0
-4.0
-2.0
0.0
2.0
1 week 2 months 7 months 12 months
Time relative to DMSD Installation
Change in
85th %ile Speed
(MPH)
Hugo DSMD
Stonebridge Control
Average All DSMD sites
-7.0 MPH -6.8 MPH-6.3 MPH
-7.5 MPH
Persistent Effect on Driver Speed Behavior
Data was collected over the course of one full year to assess the long-term effect of DSMD signs
on drivers’ speed. Speed and traffic volume data were collected in advance of the speed limit
transition area and at the speed transition prior to installing the DSMD signs and at regular
intervals afterwards. Analysis of the data showed both statistically significant and, more
importantly, practically significant reductions in vehicle speeds associated with the use of the
DSMD assembly. At the Hugo Advance location, the Before 85th percentile speed was 57 mph
(posted Speed Limit of 50 mph) and the 10-mph Pace of 46-55 mph made up of 65 percent of
vehicles. Over the course of the study period, the 85th percentile speeds remained relatively
consistent at approximately 57 mph for each of the time frames (Figure 3).
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Figure 3 - Changes in 24-hour Speed Distribution at the Hugo Advance site (Speed Limit
50 mph)
Advance location at Hugo Study site (posted Speed Limit = 50
At the location of the existing speed limit sign indicating the new reduced speed limit, the 85th
percentile speed in the Before period was 50 mph (the posted speed limit is 30 mph) with the 10-
mph Pace of 41-50 mph made up of 63 percent of the vehicles. One week after the installation
of the DSMD sign assembly, there was a six mph decrease in the 85th percentile speed, from 50
mph down to 44 mph (Figure 4). One year after installation, there was still a seven mph
reduction in the 85th percentile speeds relative to the Before period. Not only did the 85th
percentile speed decrease and stay down, but all speeds decreased, with the higher speeds (95th
percentile) showing an even larger decrease of up to nine mph over time. Additionally, the 10-
mph Pace dropped by 10 mph from an initial 41-50 mph to 31-40 mph within the first week and
was still 31-40 mph at one year while maintaining essentially the same percentage of vehicles
(63% Before versus 64 % After one year).
30
35
40
45
50
55
60
65
70
Before 1 week 2 months 7 months 1 year
Time -relative to DSMD installationTraffic Speed, mph 25th
50th (Median)
75th
85th
95th
Percentile
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Figure 4 - Changes in 24-hour Speed Distribution at the Hugo DSMD Site (Speed Limit 30
mph)
DSMD location at Hugo Study site (posted Speed Limit = 30 mph)
The data showed the overall results across all the DSMD sign locations were fairly consistent.
The study found:
•Speed reductions of approximately 6-8 mph in the 85th percentile speed.
•Decrease of 10 mph in the 10 mph Pace
•Consistent reductions through all time frames including the 24-hour data, AM peak hour,
and PM peak hour.
•Consistent shift in the speed distribution to lower speeds.
CONCLUSIONS
Speeding is and will continue to be a safety concern for users on all roadways. From an
Engineering perspective, the toolbox is relatively limited on how to address speeding on
roadways. In the past, the use of law enforcement officials has been the main tool to “combat”
speeders. An emerging technology, the Dynamic Speed Monitoring Display (DSMD) sign, now
provides the Engineer with another tool to utilize. A DSMD sign in combination with a
regulatory speed sign provides direct and relevant information to the motorist using the roadway.
This information component provides the driver with immediate feedback on their behavior
relative to the posted speed.
The goal of this study was to focus on reducing and managing speeds in transition zones where
the speed limit changes from a higher speed (e.g. 50 mph) to a lower speed (e.g. 35 mph). The
20
25
30
35
40
45
50
55
60
Before 1 week 2 months 7 months 1 year
Time - relative to DSMD installationTraffic Speed, mph25th
50th (Median)
75th
85th
95th
Percentile
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results of the study show that DSMD signs at transitions zones have a significant long-term (one
year or greater) positive effect on driver speed. This study found overall decreases in speed of
approximate six to eight mph at the transition point.
In addition to the improved speed conformance, the installation of these signs proved extremely
popular with drivers, nearby residents and businesses, as well as with elected officials.
With the installation of the DSMD signs, expect:
• A reduction in overall speeds
• Increased conformance with posted speeds
• Positive public/elected official feedback
The DSMD sign in combination with a standard regulatory speed limit sign was found to be an
effective long-term speed management solution at speed limit transitions.
ACKNOWLEDGEMENTS
This project was a collaborative effort between the Washington County, Dakota County and
Ramsey County Departments of Transportation. The authors would like to recognize the efforts
of Jeff Bednar and the professional staff of SRF Consulting Group, Inc. for coordinating and
conducting the data collection. The authors would also like to recognize the participation of
David Burns, 3M Traffic Safety Systems, in the design of the experiment and his assistance with
the statistical analysis of the data.
AUTHORS
Wayne Sandberg, P.E.
Deputy Director / Assistant County
Engineer
Washington County
11660 Myeron Road North
Stillwater, MN 55082
Phone: 651-430-4339
Fax: 651-430-4350
wayne.sandberg@co.washington.mn.us
Ted Schoenecker, P.E.
Transportation Engineer
Washington County
11660 Myeron Road North
Stillwater, MN 55082
Phone: 651-430-4319
Fax: 651-430-4350
ted.schoenecker@co.washington.mn.us
Kristi Sebastian, P.E., P.T.O.E
Traffic Engineer
Dakota County
14955 Galaxie Avenue,
Transportation Department
Apple Valley, MN 55124
Phone: 952-891-7178
Fax: 952-891-7127
kristi.Sebastian@co.dakota.mn.us
Dan Soler, P.E.
Traffic Engineer
Ramsey County
1425 Paul Kirkwold Drive
Arden Hills, MN 55112
Phone: 651-266-7114
Fax: 651-266-7710
dan.soler@co.ramsey.mn.us
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REFERENCES
1. Synthesis of Safety Research Related to Speed and Speed Management, FHWA-RD-
98-154 (July 1998). Available on-line athttp://www.tfhrc.gov/safety/speed/spdtoc.htm
2. Pesti, G. and P.T. McCoy, “Long-Term Effectiveness of Speed Monitoring Displays
in Work Zones on Rural Interstate Highways”. In Transportation Research Record:
Journal of the Transportation Research Board, No. 1754, TRB, National Research
Council, Washington, D.C., 2001, pp. 21-30.
3. Casey, S. M. and A.K. Lund. “The Effects of Mobile Roadside Speedometers on
Traffic Speeds.” Accident Analysis and Prevention, Vol. 25, 1993, pp. 627-634
4. Chang, K., M. Nolan and N.L. Nihan, “Radar Speed Signs on Neighborhood Streets:
An Effective Traffic Calming Device?”, Proceedings of the 2004 ITE Annual
Meeting, Lake Buena Vista, Florida.
5. Lee, C., Sangsoo Lee, Bongsoo Choi, and Youngtae Oh, “Effectiveness of Speed
Monitoring Displays in Speed Reduction in School Zones,” In TRB 85th Annual
Meeting: Compendium of Papers. CD-ROM. TRB, National Research Council,
Washington, D.C., 2006, Paper 06-0818.
6. Garber, N. J., and S. Srinivasan. “Influence of Exposure Duration on the
Effectiveness of Changeable Message Signs in Controlling Vehicle Speeds at Work
Zones.” In Transportation Research Record: Journal of the Transportation Research
Board, No. 1650, TRB, National Research Council, Washington, D.C., 1998, pp. 62-
70.
7. Ullman, G.L., and E.R. Rose. Evaluation of Dynamic Speed Display Signs (DSDS).
In TRB 2005 Annual Meeting CD-ROM, TRB, National Research Council,
Washington, D.C., 2005, Paper No. 05-2304.
8. Manual of Transportation Engineering Studies, H. Douglas Robertson, Editor,
Institute of Transportation Engineers, Prentice-Hall, Inc. (1994).
9. Manual on Uniform Traffic Control Devices for Street and Highways, US
Department of Transportation, Federal Highway Administration, 2003 Edition.
10. NEMA TS 4: Hardware Standards for dynamic Message Signs (DMS) with NTCIP
Requirements, National Electrical Manufacturers Association (NEMA), Rosslyn,
Virginia (2005).
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COUNTERMEASURES THAT WORK
SPEEDING AND SPEED MANAGEMENT
COUNTERMEASURES
OTHER STRATEGIES FOR BEHAVIOR CHANGE
Dynamic Speed Display/Feedback Signs
Effectiveness:
Cost:$
Use:High
Time:Short
Unstaffed speed display devices, also known as speed feedback signs, which can be portable (on
trailers) or permanently installed, can show drivers that they are speeding and may encourage some
drivers to slow down. These feedback signs (with radar to detect speeds) may also suggest to drivers
that speeds are being monitored or enforcement is nearby. Portable changeable message signs
(PCMS) are a similar device that can be triggered by speeding but display a message such as “Slow
Down Now.”
Automated speed display monitors also provide a method to collect location-specific travel speed
data. A meta-analysis of dynamic speed feedback devices found that these devices are effective at
reducing speed at installation locations for different vehicle types across a variety of roadway
contexts (Fisher et al., 2021).
Use:
Use of permanent installations seems to be growing but the actual number of displays and signs in
use is unknown. Use of the displays tend to occur in work zones, school zone, transitional zones, and
curves.
Effectiveness:
Several studies have shown these signs can slow speeds while in use. A high-quality multi-site study
for FHWA has also documented crash reductions. However, speeds seem to rebound quickly
downstream and as soon as the devices are removed (Donnell & Cruzado, 2008; Hajbabaie et al.,
2011; Walter & Broughton, 2011), prompting recent efforts to evaluate permanent installations. Most
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studies have evaluated use of these devices in school zones, work zones, and other risky locations
such as at curves.
Signs that provided either an implication that speeds were being monitored or a social norms
message (“Average Speed” at the site; “Your Speed”) were effective at reducing speeds in a 50 km/h
(31 mph) zone (Wrapson et al., 2006). Several U.S. studies have found promising reductions of
speeds in school zones in response to permanent installations of speed display or changeable
message signs (Lee et al., 2006; O’Brien & Simpson, 2012; Rose & Ullman, 2003), and little sign of
driver “habituation” to the signs during school hours (O’Brien & Simpson, 2012).
Other studies have shown that speed trailers or por table changeable message signs, which may
include speed feedback plus other messages such as “Slow Down Now” when triggered by a
threshold speed, can also be effective in reducing speeds in work zones (Brewer et al., 2006; Mattox
et al., 2007). In work zones, a combination of a parked police vehicle and speed feedback trailer
reduced average and 85th percentile traffic stream speeds and free flow speeds to a similar degree as
automated camera enforcement, whereas the effect of speed trailers alone was the same as no
treatment. The presence of parked police alone was also effective, but to a lesser extent than the
combination of police + trailer or the camera system. The number of speeders above 10 mph over the
limit was essentially reduced to zero by both the automated enforcement and police + trailer
combination. However, the treatment effects on speeds in work zones disappeared within 40 – 50
minutes of removal (Hajbabaie et al., 2011).
Permanently installed dynamic speed display signs also decreased speeds and crashes at rural, two-
lane curves (speed limits 50 to 60 mph). A high-quality evaluation of dynamic speed display or curve
warning signs installed at 22 rural, two-lane sites in 7 States estimated that crashes were decreased
by 5 to 7% (Hallmark et al., 2015). The evaluators tested speed feedback signs and dynamically
activated curve warning signs with the message “Slow Down” when motorists exceeded the 50th
percentile speed on sites selected for speeding and crash problems. The speed sign displayed the
vehicle’s actual speed, up to a cer tain threshold, which was selected to avoid the possibility that
displaying actual speeds would encourage some motorists to test their speeds above this level. Once
this maximum speed was displayed, the signs replaced the number or message with the actual speed
limit or advisory limit. The evaluation found both sign types reduced the average mean speed and
proportions of vehicles exceeding by 5, 10, 15, and 20 mph at 1 month, 12 months, and 24 months
after installation at most locations. Although trends suggested the speed feedback signs were
slightly more effective at reducing speeds at more sites compared to the “slow down” signs,
statistical tests could not confirm this trend.
In summary, use of travel speed or other speed feedback messages displayed only when the motorist
is exceeding a threshold speed can be effective at slowing speeds when used at locations where
drivers can perceive the need to slow (school zones, curves, work zones). Use of visible law
enforcement presence may enhance effectiveness. Some drivers may not reduce speed in response
to these devices unless they perceive that law enforcement is nearby.
Cost:
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Hallmark et al. (2015), identified reliable, durable (would last at least 2 years) systems that cost less
than $10,000 per sign for installation, support, and maintenance for a curve-based permanent speed
feedback sign evaluation, but some types of signs did experience technical issues.(Signs may be
powered with solar panels.)
Time to Implement:
Once law enforcement agencies and engineering safety partners have determined locations where
dynamic speed display may help to control speeds, implementation time should be fairly short.
Other considerations:
Work zones: See NCHRP Report 746 (Ullman et al., 2013) for in-depth discussion of
advantages, disadvantages, and deployment considerations for various methods of traffic
enforcement in work zones. According to this report, there have been insufficient controlled
trials to identify the optimal mix of enforcement types and other treatments for different
highway types, geometries, and work zone situations. The report reiterates the impor tance
of work zone speed limits that reflect the situation, including the presence of workers or
alignment changes. A study of speed controlling strategies before freeway (repaving) work
zones in Oregon recommended using a combination of reduced speed limit signs, portable
changeable message signs, and speed feedback signs based on reductions in speed
achieved with different combinations of these treatments (Gambatese & Zhang, 2014).
There is more information about deployment in the repor t.
Prev: Other Strategies for Behavior Change | Next: Intelligent Speed Assistance
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Page 25 of 27
2.b
City Council Work Session Memo
MEETING DATE: April 21, 2026
TO: Mayor, City Council and City Administrator
FROM: Kelly Torkelson, Assistant City Administrator
SUBJECT: Performance Measure Report
ACTION REQUEST:
Staff is looking for initial comments from the City Council on whether suggested measures
reflect the Council's 2025-2026 operational goal for developing organizational performance
measures.
BACKGROUND:
The City Council has established four strategic priorities that guide the work of the City. City
programs, services, and initiatives are aligned to support one or more of these priorities. Each
year, the City advances a range of initiatives designed to further these strategic priorities. These
efforts often span multiple priority areas and involve coordination across departments to
achieve outcomes.
The draft report will demonstrate the strategic priority outcomes from 2025 and will be
organized into four sections, one for each strategic priority, and includes both qualitative
descriptions of initiatives and quantitative performance measures.
Staff is looking for feedback from the City Council if this report reflects their goals for the
2025-2026 City Council operational goal of developing organizational performance measures
or if there is more information the council would like to see represented before staff present
the report to the City Council and public during a City Council meeting.
ATTACHMENTS:
None
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2.c
City Council Work Session Memo
MEETING DATE: April 21, 2026
TO: Mayor, City Council and City Administrator
FROM: Meredith Lawrence, Parks and Recreation/Assistant Public Works Director
SUBJECT: Independence Day/250th Anniversary Event Update
ACTION REQUEST:
Informational. Staff will provide a brief update on the event plan for the 250th anniversary of
the United States.
BACKGROUND:
The City Council asked staff to plan a 2026 Independence Day Event in celebration of the
County's 250th anniversary—in addition to the annual fireworks celebration.
ATTACHMENTS:
None
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