HomeMy WebLinkAbout8/21/2002 - STAFF REPORTS (11) DATE:
TO: City Council
FROM: Director of Public Works/City Engineer
NEIGHBORHOOD TRAFFIC CALMING PROGRAM
RECOMMENDATION:
It is recommended that the City Council approve and adopt the City of Palm Springs
Neighborhood Traffic Calming Program.
SUMMARY:
Concern from residents regarding traffic speeds and volumes are at an all time high
and are increasing on a weekly basis Recently developed tools, collectively called
"Neighborhood Traffic Calming", have provided the Traffic Engineering industry with
more ways to reduce the negative effects of vehicle use, alter driver behavior and
improve conditions for pedestrian and other users. Staff is requesting the
implementation of a program to guide them in how the City Council would like these
tools used in Palm Springs. This program will also serve to prioritize traffic calming
requests, based on specific data of the identified issue.
BACKGROUND.
In the past when a resident called to complain about traffic speed or volume in their
neighborhood, staff would conduct a traffic and engineering survey to validate the
complaint. If the complaint was valid, staff would refer the problem to the police
department for enforcement. Although increased enforcement generally provides
a temporary reduction in trafficspeeds, once enforcement is complete traffic usually
returns to its normal pattern. If enforcement cannot correct a speed problem the City
may end up increasing the speed limit to comply with state speed laws. This
increase may not be desirable to the City or it's residents.
Neighborhood Traffic Calming allows the City to choose roadway characteristics that
produce the desired speed limit and volume for each roadway. The key word here
is "desired", which must be a combination of property owners' and residents'
opinions, along with the City's General Plan requirements as approved by City
Council.
The concept of developing a Neighborhood Traffic Calming Program was discussed
at the March 20, 2002, City Council meeting, two Council Study Sessions, as well
as three separate neighborhood meetings over the last year At the March 20, 2002,
meeting, Council suggested clarification wording, which has now been incorporated
into the document, specifically on page 10 regarding possible fees, on page 13
concerning notification of any financial commitment being required of the
neighborhood, and on the page 19 Table showing that median islands would
contribute to speed reduction. Council also asked that the draft plan be submitted
to the City Attorney for review. Comments have been received from the City
Attorney and his suggestions have also been incorporated within the plan along with
all previously received citizen input.
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Neighborhood Traffic Calming Program
July 17, 2002
Page 2
The primary purpose of the program is to provide a structured means to address
neighborhood concerns over traffic safety. Once the neighborhood's concerns have
been properly identified, City staff will work with the neighborhood to develop
responsible measures that consider the "4E's" or Education, Enforcement,
Engineering and Enhancement. Elements of one or more of the '4E's" may be
incorporated into the traffic calming plan and presented to the City Council for its
consideration.
SUBMITTED: -,- �✓ A-�_
DAVID J. BARAKIAN
Director of Public Works, City Engineer
APPROVED:-?.:-
City Manager
Attachments:
1. Minute Order
2. Traffic Calming Program
Neighborhood
Traffic
Calming
Prog ra m
City of Palm Springs
Department of Public Works and Engineering
David J. Barakian, City Engineer
Richard B.Jenkins,Traffic Engineering Coordinator
July 2002
Punted 3-7u1-02
-9A3
Table of Contents
1. Introduction 3
What is Traffic Calming? 3
Multiple Purposes of Traffic Calming 3
An Integrated Approach to Traffic Calming 4
Future Program Updates 5
What's Included in this Policy? 5
2. Traffic Calming Impacts 6
Travel Speeds 6
Traffic Volumes 7
Collisions
8
Emergency Responsiveness 8
3. Implementation Process 10
Community Identification of the Problem 10
Level 1 Implementation Process 11
Level 2Implementation Process 12
Funding Considerations 14
4. Guidelines for Installation 15
Speed Hump Guidelines 15
Crosswalk Guidelines 15
Stop Sign Guidelines 15
Appendix
Traffic Calming Toolbox 17
Application of Tools 17
Level 1 Traffic Calming Tools 17
Level 2 Traffic Calming Tools 26
Combining Traffic Calming Measures 26
Use of Temporary Measures 26
Implementation Process Chart 42
Community Action Request Form 43
Prioritization Worksheet 44
Acknowledgments 47
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1. Introduction
What is Traffic Calming?
The City of Palm Springs frequently receives complaints from its residents about speeding
and cut-through traffic in our neighborhoods. Several Palm Springs neighborhoods have
identified traffic safety and speed as high priorities needing improvement. Without proper
treatment, neighborhood livability will become more adversely affected. In response to the
public's concerns, the City of Palm Springs has developed a Neighborhood Traffic Calming
Program.
The term "traffic calming" is defined differently throughout the United States and the
world. The Institute of Transportation Engineers, an international education and scientific
association of transportation professionals, defines traffic calming as follows:
Traffic calming is the combination of mainly physical measures that reduce the
negative effects of motor vehicle use, alter driver behavior and improve conditions
for non-motorized street users.
The City of Palm Springs expands this definition to also include consideration of non-
physical measures, such as educational programs and enhanced enforcement.
Multiple Purposes of Traffic Calming
The immediate purpose of traffic calming is to reduce the speed and volume of traffic to
acceptable levels. Reductions in traffic speed and volume, however, are just means to
other ends such as traffic safety and active street life. Traffic calming is undertaken for
many different reasons, including:
➢ Reducing through traffic
➢ Reducing truck traffic
➢ Reducing the occurrence of excessive speeding
➢ Reducing noise, vibration and air pollution
➢ Reducing accidents
➢ Providing safer environment for pedestrians and children
➢ Reducing crime
➢ Supporting redevelopment
As discussed later, many different traffic calming tools are available to achieve the above
goals.
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An Integrated Approach to Traffic Calming
The City of Palm Springs'Traffic Calming Program addresses the issue many residents have
expressed, namely "Too many cars, going too fast by my house," by working closely with
residents to identify existing problems, define neighborhood goals, and garner community
support. The program relies heavily on community participation and action.
After the identification of a neighborhood problem, City staff and residents use an
integrated approach to develop reasonable measures that consider the"4Es":
Education
Enforcement
Engineering
Enhancement
➢ Education: Residents are provided with information and tools necessary to make
informed decisions about neighborhood traffic concerns.
➢ Enforcement: Community identified strategies can be put into effect through
targeted traffic enforcement.
➢ Engineering: Through a City staff and resident partnership, physical traffic calming
strategies are developed based on engineering principles, community input, and
financial feasibility.
➢ Enhancement: Design and landscaping features can be used to improve the
aesthetics and livability of neighborhoods and to enhance many physical measures.
Elements of one or more of the"4Es"are incorporated into all of the traffic calming tools
considered by the City. After development of a community-driven neighborhood traffic
calming plan, actions may be implemented using a staged approach.
Level 1 actions may be implemented first. Level 1 measures consist of easily
implementable, low-cost, and often less controversial tools such as neighborhood traffic
safety campaigns, radar speed display units, neighborhood speed watch programs,
targeted police enforcement, sign installation, and pavement marking changes.
If it is determined, that more assertive measures need to be implemented, Level 2
improvements may be considered. Level 2 actions alter the configuration of neighborhood
streets, so they often require engineering, are higher-cost, and require community
consensus prior to installation. Level 2 measures consist of physical devices such as speed
humps, traffic circles, curb extensions, median islands, and other measures described
within this Policy. Level 1 measures need not be implemented prior to implementing Level
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2 measures.
The City's integrated traffic calming approach includes an essential community involvement
program. Community involvement and buy-in is a prerequisite. Because for every action
there is an opposite reaction, be it diversion of traffic to another roadway, or neighborhood
opposition to particular traffic calming devices, the success of City traffic calming projects
depend on considerable resident involvement.
Future Program Updates
The City of Palm Springs' Neighborhood Traffic Calming Program is considered a living
document. It will be updated from time to time as new traffic calming techniques are
developed and tested. As the City's neighborhoods gain more experience with traffic
calming, procedures may be revised. In addition, traffic calming device installation
guidelines will be added as they are developed.
What's Included in this Policy?
The City of Palm Springs'Neighborhood Traffic Calming Program Policy is divided into the
following five chapters:
➢ Chapter 1. Introduction: This chapter, which provides an overview of the City of
Palm Springs'Traffic Calming Program.
➢ Chapter 2. Traffic Calming Toolbox: Presents descriptions of various Level 1 and
Level 2 traffic calming tools.
➢ Chapter 3. Traffic Calming Impacts: Provides discussion of travel speed and
volume, collision potential, and emergency response impacts.
➢ Chapter 4. Implementation Process: Discusses the City of Palm Springs'integrated
and community-driven traffic calming approach.
➢ Appendix. Guidelines for Installation: The Appendix includes suggested guidelines
for the installation of various traffic calming tools.
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2. Traffic Calming Impacts
This chapter describes impacts of different types of traffic calming measures. Using
qualitative and quantitative data available from before-and-after studies, the ability of
various Level 2 devices to reduce travel speeds, cut-through traffic volumes, and collision
potentials are discussed. In addition, the impact of traffic calming measures on emergency
responsiveness is presented. Level 1 impacts are not discussed since very few before-and-
after studies have been conducted on these type of traffic calming improvements.
Travel Speeds
One of the primary goals of traffic calming is to reduce travel speeds on residential streets.
In traffic engineering, speed distributions are typically represented by 85th percentile
speeds since most studies show that at least 85 percent of the drivers operate at speeds
which are reasonable and prudent for the conditions relative in each situation. Most of the
speed data available from before-and-after studies of traffic calming are 85th percentile
speeds.
Table 2.1 summarizes the speed impacts of various traffic calming measures. The data
shown in the table are based on the results of hundreds of before-and-after studies.
Table 2.1 Speed Impacts Downstream of Traffic Calming Measures
85tl'Percentile Speed
Sample m�h
Measure Sample
Avg. Avg. Change Percentage
Before After After
Calming Calming Calming
Speed Hump 179 35.0 27.4 -7.6 -22
9
Raised Crosswalk 58 36.7 30.1 -6.6 -18
2.7 3.2 8
Raised Intersection 3 34.6 34.3 -0.3 -1
6.0 3.8 10
Traffic Circle 45 34.2 30.3 -3.9 -11
4.4 3.2 10
Narrowing 7 34.9 32.3 -2.6 -4
2.8 5.5 22
Entrance Barrier 16 32.3 26.3 -6.0 -19
5.2 5.2 11
Diagonal 77 29 3 27.9 1.4 4
Source:" rafficcalfing are of the cute,"n7r August 9. 5.2 4.7 17
Measurements within the parentheses represent the standard deviation from the average.
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As shown in Table 2.1, speed humps have the greatest impact on 85th percentile speeds,
reducing them by an average of more than seven miles per hour (mph), or 20 percent.
Raised intersections and traffic circles have the least impact.
It should be noted that the speed impacts of traffic calming measures rely not only on the
geometrics of the device, but the spacing between successive devices. Previous studies
indicate that speeds increase about 0.5 to 1.0 mph for every 100 feet of separation for
speed hump spacing up to 1,000 feet.
Traffic Volumes
Another primary goal of traffic calming is to reduce cut-through traffic volumes on
residential streets. Traffic volume impacts are much more complex and site-specific as
compared to speed impacts because of the availability of alternative routes and the split of
traffic between localized trips (that need to travel along the traffic calmed location) and
through traffic (which can often take another route).
Although traffic volume changes are difficult to assess, based on previous studies, two
measures of impact are summarized in Table 2.2. The table provides information on
average percentage change in daily traffic volumes after treatment. The results shown in
Table 2.2 should be viewed as representative only.
Table 2.2 Speed Impacts Downstream of Traffic Calming (Measures
Sample Measure Sample Size Average Percent Change in Volume*
vehicles per day)
Speed Humps 143 -18
24
Raised Crosswalks 46 -12
20
Traffic Circle 49 -5
46
Narrowing 11 -10
51
Entrance Barrier 53 -42
41
Diagonal Diverter 27 -35
46
Full Closure 19 -44
36
Source:'Traffic Calming,State of the Practice,"rrE,August 1999.
Measurements within the parentheses represent the standard deviation from the average.
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Traffic volume changes are usually the greatest when roadway closure devices are used,
such as entrance barriers, diagonal diverters and cul-de-sacs. Of Level 2 measures,traffic
circles typically have the least effect in reducing traffic volumes.
It should also be pointed out that while implementation of certain traffic calming devices
can reduce traffic volumes along the intended route,they may also increase traffic volumes
along nearby residential streets. This potential impact should be considered before
deciding on which traffic calming tools are to be implemented.
Collisions
By slowing traffic, eliminating conflicting movements, and increasing drivers' attention,
traffic calming can result in fewer collisions. And, due to lower speeds, they are often less
serious when collisions do occur.
Table 2.3 compares before-and-after collision frequencies for various Level 2 traffic calming
measures. As shown, several traffic calming devices reduce the potential for collisions.
Traffic circles are very effective as they lower the number of potential vehicle conflict points
(since no left-turn or straight-through movements are allowed).
Table 2.3 Average Annual Collision Frequenciles
Before and After Traffic Calming
Sample Average Annual Collisions
Sample Measure Size Before Percentage
Calming After Calming Chan e
Speed Hump 50 2.62 2.29 -13
Raised Crosswalk 8 6.71 3.66 -45
Traffic Circle 130 2.19 .064 -71
Source: Unpublished documents supplied by traffic calming programs.
Many traffic calming measures not only reduce the potential for collisions between two or
more vehicles, but also between vehicles and pedestrians or between vehicles and
bicyclists. Several treatments improve the sight distance between these modes, and/or
provide safe refuge areas for crossing pedestrians and bicyclists. On the other hand, some
measures that reduce travel lane widths could increase the potential for conflicts between
vehicles and bicyclists.
Emergency Responsiveness
Many traffic calming tools that are effective due to their ability to physically control traffic
circulation can also negatively impact several classes of emergency vehicles. The City of
Palm Springs and its residents place a very high priority on minimizing emergency response
time.
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Several localities have performed controlled tests of speed humps, raised crosswalks, and
traffic circles to see how much delay they produce. Table 2.4 presents the test results.
Table 2.4 Emergency Response Time Studies Results
Community Measure Celay at Slow Point
seconds
Austin,TX 12'Speed Hump 2.8(fire engine)
3.0(ladder truck)
2.3(ambulance w/out patient)
9.7 ambulance withpatient)
Berkeley,CA 12'Speed Hump 10.7(fire engine)
9.2(ladder truck)
22'Raised Crosswalk 3.0(fire engine)
13.5 ladder truck
Boulder,CO 12'Speed Hump 2.8(fire trunk)
25'Traffic Circle 7.5 fire engine)
Montgomery Co.,MD 12'Speed Hump 2.8(ladder truck)
3.8(ambulance)
4.2(fire truck)
18'Traffic Circle 5.4(ladder Vruck)
3.2(ambulance)
5.0(fire truck)
7.0 um r truck
Portland,OR* 14'Speed Hump 5.2(fire engine)
2.9(custom rescue vehicle)
6.6(ladder truck)
22'Raised Crosswalk 3.0(fire engine)
0.3(custom rescue vehicle)
3.0(ladder truck)
16'-24'TrafficCircle 6.1(fire engine)
3.1(custom rescue vehicle)
8.4 ladder truck
Sarasota FL 1 12'Speed Hump 9.5 ambulance
*Assumes a 35-mph response wising speed.
Source:"Traffic Calming,State of the Practice,"IFE,August 1999.
As shown in Table 2.4, regardless of the traffic calming measure or fire-rescue vehicle,the
delay per traffic calming measure is often under 10 seconds. Traffic circles appear to
create longer delays than speed humps, but speed humps have a greater probability of
damage to fire-rescue vehicles and injury to patients in ambulances. Finally, raised
crosswalks, because they are longer, create shorter delays than speed humps.
Consideration of traffic calming devices will always include a review of possible negative
impacts, including emergency response times.
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3. Implementation Process
The City of Palm Springs' Neighborhood Traffic Calming Program is based on substantial
community participation. Because residents are primarily the initiators of traffic calming
requests and must live day-to-day with the resulting actions, the City includes
neighborhood participation throughout the process. Development of successful traffic
calming programs depends on a strong interaction between the community and City staff.
One of the intents of the program is to provide a clear structure for addressing traffic
concerns in the City's neighborhoods. Traffic concerns may exist throughout an entire
neighborhood, or may be specific to a particular street, segment of roadway, or at a spot
location. The City's implementation process consists of two levels, as shown on Page 42.
Both levels require, as a first step, community or City staff identification of existing
problems. The process allows implementation of traffic calming tools in a timely manner in
conditions where problems could be addressed with fairly routine solutions.
Community Identification of the Problem
The traffic calming process begins once the City's Department of Public Works and
Engineering receives a request from a neighborhood to initiate a study or the Department
identifies a traffic problem through its regular review of traffic statistics. In the case of a
neighborhood-initiated request, a resident or a group of residents must complete a
Community Action Request form. The form must include a discussion of the current traffic
problems and the names and signatures of at least five other affected property owners
supporting the request to initiate a study. A Community Action Request form is provided
within this chapter. The requesting party(ies) may be charged a fee per speed survey
location.
Upon receipt of the Community Action Request form,the City's Department of Public Works
and Engineering will document the neighborhood concern, conduct a field investigation,
and collect data, as appropriate(e.g., traffic volumes, collision data,travel speeds,etc.). If
City staff determines that the neighborhood's identified problem can be easily reduced or
alleviated with a Level I action (e.g., easily implementable and low cost tools, primarily
consisting of education and enforcement techniques),the City will propose implementation
of the most appropriate Level I improvement(s) at a neighborhood meeting.
After collecting survey information, City staff will evaluate the need for traffic calming. If
the need for traffic calming is not supported by the data collected, a report will be issued to
the requesting party(ies). If traffic calming is supported by the data, the Public Works and
Engineering Department will contact the City of Palm Springs Office of Neighborhood
Involvement and Public Participation and request that a neighborhood meeting be held to
discuss the finding and form a neighborhood work group meeting. This procedure will also
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serve as the first step in the case of a Department identified problem. The group will work
with City staff to identify the most effective solutions to the identified problem. Solution
consensus will place the necessary project improvements on the list for prioritization.
The prioritization process provides the City with clear guidelines on how to manage its
limited resources effectively and appropriately when dealing with citywide traffic calming
needs. It is also allows the City to work with the neighborhoods that have the most
pressing problems first. When a particular location reaches the top of the City's
prioritization list, it will enter into the next phase of the traffic calming implementation
process.
Level 1 Implementation Process
City staff will review the neighborhood priority process annually. When a specific
neighborhood problem is identified, City staff will arrange an initial neighborhood meeting
with the assistance of those residents that signed the original Community Action Request
form. This will occur according to the problem's priority listing. At the meeting, City staff
will present findings from the initial field investigation and data collection phase, and
provide a presentation of the City of Palm Springs'Neighborhood Traffic Calming Program.
A volunteer group of residents chosen by the neighborhood participants will form the
project's Community Working Group.The community working group will be responsible for
arranging subsequent group meetings and shall keep their neighborhood constituents
informed as to progress. A goal is to have members that represent the various
geographical areas and interests within the neighborhood. City Staff will arrange and
provide the location for the initial meeting.
The Community Working Group will work with City staff in an advisory role and will meet to
review existing problems, determine community goals, establish the neighborhood study
boundary, discuss and evaluate various measures, and gain community acceptance on
which measures to implement as means of addressing the problems. The group will also
determine how long to implement the recommended improvements, although a minimum
testing period of three months will be required.
Upon approval by the Group and City staff, the appropriate improvements will be further
prioritized for installation, in accordance with the Council approved Capital Improvement
budget. Following the pre-established implementation period, City .staff will collect new
data to determine the effectiveness of the measures put into place. The Community
Working Group will then meet to discuss if their goals have been met.
If the prescribed actions have proven effective in addressing the goals, the improvements
will stay in place or permanent devices will be installed. If the actions are ineffective, the
Community Working Group may consider reapplying for a traffic calming plan or pursue
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potential implementation of Level 2 measures. A discussion of this process is provided
below.
Level 2 Implementation Process
Level 2 traffic calming improvements may be considered if Level 1 measures do not meet
the goals established by the Community Working Group, as previously discussed. In
special circumstances, City staff may determine that Level 1 measures cannot achieve the
desired outcomes and may recommend immediate consideration of Level 2 measures.
Projects that move into Level 2 consider physical travel speed and traffic volume reduction
measures and therefore require increased neighborhood consensus.
Before a Level 2 program can commence for a particular neighborhood, residents and
property owners within the study area boundary will be surveyed to determine their level of
support in considering Level 2 improvements. The City's Department of Public Works and
Engineering,Traffic Management Center, in conjunction with City of Palm Springs Office of
Neighborhood Involvement and Public Participation will conduct the survey. A minimum of
one third of those surveyed must agree to proceed in developing an expanded plan. If less
than one third agree, then Level 2 improvements will not be considered.
If the vote supports consideration of Level 2 measures,the Community Working Group will
be formed or reestablished. It may be necessary to expand or otherwise alter the
composition of the initial group (if any) due to the likely greater impacts that could result
under a Level 2 traffic calming plan.
City staff will work with the Community Working Group in an attempt to identify as many
stakeholders that will be directly effected as possible. Their perspective is essential for
developing a plan that effectively addresses existing concerns without creating new
problems.
The Community Working Group will meet to review, or revisit existing problems and
community goals, and identify the appropriateness of various Level 2 measures in
addressing the existing problems. City staff will collect, sometimes with neighborhood
support, additional data to support the process (e.g., delay studies, vehicle license plate
studies, etc.). City staff will assist the Community Working Group in developing a Level 2
traffic calming plan (note that the plan may contain some Level 1 types of measures).
Next, the Community Working Group will present the proposed Level 21 traffic calming plan
(which may consist of alternatives) to neighborhood residents and property owners at a
neighborhood meeting. In addition, the plan may be presented though a newsletter or
other type of mailing. The City will assist the neighborhood in these efforts. However, it is
vital that the Community Working Group also work to gather support for the project.
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After the neighborhood meeting, residents and property owners may be asked to vote on
whether or not to conduct a temporary test of the proposed Level 2 traffic calming plan. A
vote will generally occur if a solid consensus is not reached at the open house. At least 60
percent of the residents and property owners (household locations will be determined by
City staff and the working group)that could be affected by the proposed changes in traffic
flow must favor implementation of Level 2 measures in order to proceed. In addition, at
least 75 percent of the residents and property owners immediately adjacent to each
proposed device must favor implementation. One vote will be granted to each residence
and/or property owner. The voting period will last up to four weeks. In order for the vote
to be considered valid, a minimum of one third of all of those balloted must respond.
In some cases, neighborhood participation in funding a proposed Level 2 plan may be
necessary. If a financial commitment is required from the neighborhood, this stipulation
will be included in the ballot, along with the estimated total cost and proposed
apportionment to each individual property owner.
After conclusion of the voting process, City staff will notify residents and property owners
about the ballot results. If the Level 2 traffic calming plan does not receive enough votes
for testing, the proposed devices will not be installed. The community may re-apply for a
traffic calming plan in three years or sooner if special circumstances indicate that further
review should be considered.
If approved, the proposed Level 2 traffic calming plan will be implemented on a test basis
using temporary control devices, where possible, for a period determined by the City's
Department of Public Works and Engineering. In most cases,the test program will last one
year - with the ultimate duration agreed to by the Community Working Group in
conjunction with City staff.
Following the test period, City staff will collect new data (e.g., traffic volume counts,speed
surveys, etc.) in order to determine the effectiveness of the measures put into place.
These results will be provided to all of the neighborhood residents and property owners.
Then the devices may be installed in a permanent manner, removed,or a further vote may
be taken using the same process as described previously. Again, City staff will notify
residents and property owners about the ballot results. If permanent measures are voted
in, the Level 2 traffic calming plan will be fully implemented with permanent devices. City
staff will give notification to the neighborhood prior to construction.
After construction of the permanent Level 2 measures, the City's Department of Public
Works and Engineering will continue monitoring the effectiveness of the plan for up to one
year. City staff will prepare a report of the findings for presentation to the neighborhood.
Depending on the nature of the measures, this report could include a maintenance plan for
residents and property owners.
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Funding Considerations
Funding for the implementation of a traffic calming plan should be considered throughout
the plan development process. If funding limitations will impact the range of options
available, this needs to be identified early in the process and the variety of appropriate
devices should reflect these limitations. It must be reiterated that Level 2 devices are
expensive. Furthermore, the City's Neighborhood Traffic Calming Program operates on a
limited budget. The budget is approved annually and is contained in the City's Capital
Improvement Program.
However, if a neighborhood wants to implement a more extensive plan than what City Staff
believes is appropriate to resolve the identified problem(s), then the City Council may need
to approve the plan with additional funds and/or the neighborhood may be requested to
participate in funding all or a part of the project.
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4. Guidelines For Installation
The City of Palm Springs will continually develop recommended guidelines for the
installation of various traffic calming tools. This chapter will be updated from time to
time to provide new and/or revised guidelines for traffic calming devices. The
guidelines discussed below can be used in most circumstances; however, special
situations may sometimes apply since many streets have differing characteristics.
Speed Hump and Speed Cushion Guidelines
The following guidelines should be followed when considering the installation of speed
humps:
I. The street or street segment shall be a two lane residential local or collector street,
not found on the State or California's functional classification maps, where its
primary function is to provide access to abutting residences.
2. The street or segment shall be fully improved, i.e. includes curb and gutter or curb
and gutter shall be constructed as part of the project that constructed the humps or
cushions. Streets without full improvements may be considered if physical
conditions exist that will allow the humps or cushions to operate effectively.
3. The street segment shall be at least 600' long.
4. The installation of humps or cushions shall not adversely affect response time for
emergency service vehicles.The Department of Public Works and Engineering staff
in conjunction with potentially affected Public Safety Departments shall determine if
there is any affect to existing response times.
5. Guidelines apply to streets with a speed limit of 30 miles per hour or less.
6. The critical speed (i.e. the 85"'% speed) should be at least seven miles per hour
over the speed limit.
7. At least 50% of the traffic should exceed the speed limit.
8. The average daily traffic volume should be more than 500 vehicles per day, but less
than 3,000 vehicles per day.
Crosswalk Guidelines
Crosswalks shall not be installed unless the location demonstrates.a high concentration
of pedestrians and shall be installed in conjunction with traffic control devices such as
traffic signs. New crosswalks at uncontrolled intersection or mid-block locations shall be
strictly limited and shall be allowed only in the most urgent circumstances and if
pedestrian safety can be provided.
Stop Sign Guidelines
Stop sign installation shall be guided by the MUTCD stop sign warrants or the"Multi-
Way STOP Installation Criteria for Neighborhood Street" as found in the January-
February 1999 issue of the WesternlTE.
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Appendix
Traffic Calming Toolbox 17
Application of Tools 17
Level I Traffic Calming Tools 17
Level 2 Traffic Calming Tools 26
Combining Traffic Calming Measures 26
Use of Temporary Measures 26
Implementation Process Chart 42
Community Action Request Form 43
Prioritization Worksheet 44
Acknowledgments 45
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Traffic Calming Toolbox
Application of Tools
Traffic calming tools come in all shapes and sizes, from the subtle to the very aggressive.
Each tool has appropriate applications, limitations on its use, advantages, disadvantages,
and costs associated with it. Before considering any traffic calming tool or a combination
of tools, it is important to clearly understand the residents' concerns and the factors or
conditions that generated those concerns. For example, sometimes all that is needed to
alleviate high speeds along a residential street is increased neighborhood awareness or
enforcement of speed limits. Physical devices such as speed humps are often well suited
for speed control, but may create increased noise; therefore, if residents are concerned
with both speed and noise, the installation of speed humps may not be the best choice at
particular locations. It is important to understand all of the issues associated with each
tool to identify the most appropriate one for the circumstances.
It is also important to recognize that if cut-through traffic is the problem (as determined by
traffic counts), it suggests one set of measures. If speeding is the problem (as determined
by speed measurement), it suggests another set. High collision rates, crime, or urban
blight may suggest a third set.
The following Table provides a general assessment of traffic calming measures. Chapter 2
provides more specific detail on how various traffic calming tools affect traffic speed and
volumes, vehicle collisions, and other quality of life measures.
Level 1 Traffic Calming Tools
Level 1 measures consist of easily implementable and low-cost tools,such as neighborhood
traffic safety campaigns, radar speed display units, targeted police; enforcement, sign
installation, and pavement marking changes. Level 1 measures,as discussed in Chapter 3,
will always be implemented and tested prior to consideration of more restrictive measures.
Level 1 actions primarily consist of education and enforcement tools.
The following pages provide a gallery of potential traffic calming measures.
17
�/9
Generalized Assessment of Traffic Calming Measures
Meawre Reduces Reduces Moise Loss of Restricts Emergency
Traffic Parki Access Im cts Maint. Cost
Level 1 Measures•
DSpeedNo
Maybe No Change one None None No $250/Day
Neighborhood Ma be Minimal No
S ns y Chan a None None Non. Occasional $200/Sign
High Visibility No
Crosswalks Maybe No Change None None None Yes $1-5K
Police No
Enforcement Yes Maybe Change None None None No $75/Hr
Narrowing No
Lanes Yes Maybe Chan a None None None Yes $1-3K
Speed Limits No
Z
ing Maybe No Change None None None Occasional $200/Sign
p Maybe Maybe Increase None None Yes Occasional $200/Sign
ns
ed No yes No
tions Cha a None Yes Maybe Occasional $200/Sign
Meewres•
Island Yes Maybe Decrease Yes Yes Yes Yes $10-75K
Gateway Yes Yes Varies Maybe Yes None Yes $10-20K
Curb Extensions Yes No No Yes None Some Yes
Change
$10-20K
Chokers Yes Maybe Chan a Yes None Some Yes $10K
Speed
Humps/Cushion Yes Maybe Increase None None Yes Yes* $3-5K
s
Raised Yes Maybe Increase Yes None Yes Yes*Crosswalk $5-10K
Raised Yes Maybe Increase
Intersection y Maybe None Yes Yes $25-50K
Traffic No
Circles Yes Maybe Change Yes Yes Yes Yes $15-25K
IntersectionNo
Channelizing Yes Maybe Change Yes None None Maybe $15-20K
ChicaneNo
Yes Maybe Chan a Yes Maybe Some Maybe $20-40K
Movement Maybe Yes Decrease None Yes Yes Yes Barrier $SK
Entrance No
Barriers Maybe Yes Chan a Maybe Yes Maybe Yes $15-20K
Diagonal Maybe Yes No Maybe Yes Yes Yes Dlverter Chan Y $15-35K
Street Maybe Yes No
Closure Chan a Maybe Yes Yes Yes $20-35K
*Speed humps and raised crosswalks must be reinstalled each time a street is resurfaced.
Sources:"Neighborhood Traffic Management&Calming Program,"City of Buena Ventura,CA 1997 and Parisi Associates.
18
Speed Display Unit
Level 1
Description: The most common form of
radar speed display unit is a portable trailer 20
equipped with a radar unit that detects the : LIMIT _
speed of passing vehicles and displays it on ', c,;=
a reader board, often with a speed limit sign ,_-�
next to the display.
Application: The primary benefit of a �-_:
speed display unit is to discourage speeding _4
along neighborhood streets.
t�
Advantages: Disadvantages:
+Effective education tool. -Not an enforcement tool.
+Good public relations tool. -Ineffective on multi-lane roadways.
+Encourages speed compliance. -Less effective on high volume streets.
+Can reduce speeds temporarily. -Subject to vandalism.
Special Considerations:
• Used throughout the city on an ongoing basis.
• The purpose of the unit is to remind drivers that they are speeding.
• Encourage compliance with the posted speed limit.
• Usually only effective in reducing speeds when actually being used.
• In longer term (30 days), speeds can decrease by 6% on low volume roads.
• Effect usually negligible on higher volume streets serving through traffic.
• Some motorists may speed up to try to register a high speed.
• Should not be used in remote areas due to possible vandalism.
Cost:
• $250 per day.
19
es
s
9��1
Higher Visibility Crosswalks
Level 1
Description: Higher visibility
crosswalks can be created by
using paving blocks or
contrasting color concrete, or
painting zebra stripes in lieu of
or between the crosswalk's
outer boundary stripes, and
using flashing beacon warning
signs or flashing pavement
beacons. ----`L
1a--
Application: The primary ^�
benefit of a higher visibility
crosswalk is to increase
crosswalk visibility to drivers.
Advantages: Disadvantages:
+More visible than traditional x-walks. -Pedestrians may ignore traffic more.
+Indicates preferred crossing location. -Only used at uncontrolled crosswalks.
+Can slow travel speeds. -Usually require more maintenance
+Can be aesthetically pleasing than traditional crosswalks.
Special Considerations:
• Higher visibility crosswalks indicate preferred crossing location to pedestrians.
• Pedestrians may place too high a reliance on ability to control driver behavior.
• Specially paved types require more maintenance than traditional crosswalks.
• Should only be used at uncontrolled crosswalks.
• Less expensive, but not as effective as raised crosswalks (Level 2).
Cost:
• $1,000 to $5,000 each.
20
00M
Targeted Police Enforcement
Level 1
Description: The Police Department deploys 'r�SPEED CMECKEO
motorcycle or automobile officers to perform targeted `` •Y PA7gOL rA
P
? CONING UP i
enforcement on residential streets for at least an hour a �SEwgo YOU �.
day. 11
�pl .Ali M9 J
Application: The intended benefit of targeted police" ! � .
enforcement is to make drivers aware of local speed
limits and to reduce speeds.
kf!!WA/MWtl nn.W }�' [4I1:WIWb[eq[Lnw
W9wIIH/H.Wmm Imp IHX//w �.nMIgIxHWw/�11.
Advantages: Disadvantages:
+Visible enforcement is very effective. -Temporary measure.
+Driver awareness increased. -Requires long-term use to be effective.
+Can be used on short notice. -Fines are lower than enforcement cost.
+Can reduce speeds temporarily. -Disrupts traffic on high volume streets.
Special Considerations:
• Police enforcement is continually in effect throughout the city.
• Usually used only on neighborhood streets with documented speeding problems.
• Typically only effective while officer is actually monitoring speeds.
• Often helpful in school zones.
• May be used during a learning period when new devices are first implemented.
• Long-term benefits unsubstantiated without regular periodic enforcement.
• Expensive.
Costs:
• About $75 per hour for officer and equipment.
21
«41
��
Narrowing Lanes
Level 1
Description: On this level 1
type of measure, striping is usually :
used to create narrow lanes, often
about 10 feet wide. The unused
pavement can be used to stripe ,
bicycle and/or parking lanes.
Application: The primary
benefit of narrowing lanes through r
striping is to slow vehicle speeds.
Advantages: Disadvantage:
+Can be quickly implemented. -Increases regular maintenance.
+Slows travel speeds. -Not always perceived as effective tool.
+Improves safety. -Adds striping to neighborhood streets.
+Can be easily modified. -Increases resurfacing costs.
Special Consideration:
• Narrowed travel lanes provided "friction" and can slow vehicle speeds.
• Can be installed quickly and easily revised over time,
• Designated bicycle lanes and/or parking lanes can be created„
• Adds centerline and edge line striping to neighborhood streets.
• Can be used around curves to force vehicles to stay within lanes.
• On curves, raised dots are usually most effective on centerline.
Costs:
• $1,000 to $3,000 each.
22
0
Speed Limit Signing
Level 1
Description: 25 mile per hour speed limit signs are installed SPEED
along neighborhood streets. LIMIT
Application: The primary benefit of speed limit signing is to
encourage slower vehicle speeds along residential streets. Signs
are only installed along streets where speeding is a problem. 25
Advantages: Disadvantages:
+Clearly defines legal speed limit. -Requires on-going police enforcement.
+Can reduce speeds if enforced. -Not effective solely by itself.
+Usually popular with neighborhood. -Low sped limits may be unreasonable.
+Low cost installation. -Adds additional signs in neighborhood.
Special Considerations:
• Should only be used on streets where speeding is a documented problem.
• Requires police enforcement to remain effective.
• Speed limits lower than 25 mph can only be set by engineering analysis.
• Unrealistically low speed limits will likely result in signs being disregarded.
• Increased cost of sign maintenance.
Cost:
• $200 per sign.
23
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may
Stop Signs
Level 1
Description: Stop signs are either installed on the side
street where no signs currently exist or on the main street
at an intersection where the side street already has stop
signs.
I•�
Application: Stop signs should only be considered r'
when warranted based on established criteria.
•. r'
Advantages: Disadvantages:
+Requires traffic to stop. -May lead to increased mid-block speeds.
+Assists pedestrian crossings. -Increases noise and air pollution.
+May slightly reduce cut-thru traffic. -Can create problems if unwarranted.
+Lowers speeds at the intersection. -May increase emergency response time.
Special Considerations:
• Stop signs should only be installed if warranted based on established criteria.
• Drivers may not comply with stop signs if installation is unwarranted.
• Mid-block speeds can increase to make up for "lost" time.
• At low volume, unwarranted locations, many drivers will "roll" through.
• Can create safety problems for pedestrians when compliance is poor.
• Stop signs may increase certain types of collisions, e.g., rear-ends
• Stop signs may reduce other types of collisions, i.e., broadside collisions.
• May increase emergency response times.
• Increases noise near intersection due to vehicle deceleration and acceleration.
Cost:
• $200 per sign.
24
S�l
Restricted Movement Signing
Level 1
Description: Turn prohibition signs involve the use of
standard No Left Turn, No Right Turn, or Do Not Enter
signs to prevent undesired turning movements onto
residential streets. They may include peak period
limitations.
Application: The primary benefit of restricted ,
movement signing is to reduce cut-through traffic volumes
along residential streets. It
Advantages: Disadvantages:
+Redirects traffic to main streets. -May divert traffic to other streets.
+Reduces cut-through traffic. -Require enforcement.
+Can address time-of-day problems. -Adds more signs to neighborhood.
+Low cost. -Usually not effective all day.
Special Considerations:
• Restricted movement signing is best used on major or collector streets.
• Most effective at periphery of a neighborhood to prevent entering traffic.
• Has little or no effect on speeds for through vehicles.
• Turn prohibitions can be used on a trial basis.
• Violation rates are about 50% without enforcement.
• With active enforcement, violation rates are reduced to about: 20%.
• Turn restrictions are most effective when limited to peak hours.
• Less effective when applied around-the-clock.
• 24-hour restrictions better served with closures than with signing.
Costs:
• $200 per sign.
25
0."!
����
Level 2 Traffic Calming Tools
Level 2 actions alter the configuration of neighborhood streets, so they often require
engineering, are higher-cost, and require community acceptance prior to installation. Level
2 measures are only used after Level 1 measures have been implemented and proven
ineffective in addressing particular neighborhood traffic needs or where it is evident that a
Level 1 measure will be ineffective. Before Level 2 traffic calming actions are implemented,
the neighborhood and City staff must carefully evaluate the benefits and disadvantages of
each action.
The following pages provide a gallery of potential Level 2 traffic calming measures. It is
often possible to combine elements of various Level 2 actions or to slightly modify
treatments.
Combining Traffic Calming Measures
Often, the most effective traffic calming programs use a variety of traffic calming tools.
Combinations of traffic calming measures can be used, and are often encouraged, in
different neighborhoods and even along the same street. As shown in the toolbox of Level
1 and Level 2 applications, many of the measures complement each other. For instance,
speed humps and chokers can be used effectively together, as can traffic circles and curb
extensions. Center median islands and chokers are often installed together. Raised
crosswalks and curb extensions also work well together. Many other combinations of traffic
calming tools can be effective.
Use of Temporary Measures
Whenever feasible, the City of Palm Springs will install temporary Level 2 traffic calming
devices subject to an assessment of impacts and support of the residents. It should be
noted that while the use of temporary devices can help determine the resulting travel
speed and traffic volume changes,temporary devices are usually not aesthetic. Because of
this, there is always the risk that residents will criticize the device's appearance instead of
its effectiveness in traffic calming. However, the use of attractive materials, colors and
composition can create acceptable temporary devices. For example, planters, which can
provide landscaping opportunities, as well as access control, can be used as temporary
street closures.
26
of
Median Island
Level 2
Description: Median islands
are raised islands in the center
of a street that can be used to
narrow lanes for speed control
and/or to create a barrier to
prohibit left-turns into or from a
side street. They can also be —
used for pedestrian refuge in the
middle of a crosswalk.
Application: Median islands 1 �
are used on wide streets to
lower travel speeds and/or to
prohibit left-turning movements.
Advantages: Disadvantages:
+Effectively reduces vehicle speeds. -Could require parking removal.
+Can reduce collision potential. -May reduce driveway access.
+Reduces pedestrian crossing. -Could impact emergency vehicles.
+Opportunity for landscaping. -May create more difficult access.
+-May divert unwanted traffic volumes. -Requires additional maintenance.
Special Considerations:
• Median islands, when used to block side street access, may &vent traffic.
• In this condition, they may impact emergency response times.
• Median islands may visually enhance the street through landscaping.
• Median islands used for lane narrowing should result in a least 12' lanes.
• Fire departments usually prefer median islands to some other measures.
• Bicyclists prefer not to have travel way narrowed.
Costs:
• $10,000 to $75,000 each (depending on size).
27
oqll..
?)"111
Gateway
Level 2
Description: Gateway
entrance treatments consist of � •,;,:,
physical treatments like pillars " '<
and other vertical treatment as
well as texture treatments to the
street surface and are located at
key entryways into a
neighborhood. They often
consist of features, like chokers,
that narrow a street in order to
reduce the width of the street's
traveled way.
Application: The primary
benefit of gateway treatments is speed reduction. They provide visual cues that tell drivers
they are entering a local residential area or, that the surrounding land uses are changing.
Advantages: Disadvantages:
+Can reduce vehicle speeds. -Maintenance and irrigation needs.
+Creates identity for neighborhood. -May require removal of parking.
+Can discourage cut-through traffic. -Can impede truck movements.
+Opportunity for landscaping. -Creates physical obstruction.
Special Considerations:
• Gateways have minimal influence on driver's routine behavior.
• Overall speeds and volumes may only minimally be influenced.
• Gateway treatments make drivers more aware of neighborhood environment.
• Can incorporate neighborhood identification signing and monumentation.
• Care should be taken not to restrict pedestrian visibility at adjacent crosswalk.
• Textured pavements could introduce some new noise.
Costs:
• $10,000 to $20,000 each.
28
.3 �
Curb Extension
Level 2
Description: Curb extensions
narrow the street at the
intersection by extending the
curbs toward the center of the
roadway or by building detached
raised islands to allow for
drainage and bike lane access. s
Application: Curb extensions
are used to narrow the roadway
and to create shorter pedestrian „ -1
crossings. They also improve - . ..
sight distance and influence
driver behavior by changing the
appearance of the street.
Advantages: Disadvantages:
+Better pedestrian visibility. -Can require removal of parking.
+Shorter pedestrian crossing. -May create hazard for bicyclists.
+Can decrease vehicle speeds. -Can create drainage issues.
+Opportunity for landscaping. -Difficult for truck traffic to turn right.
Special Considerations:
• Curb extensions can be installed at intersections or mid-block (see chokers).
• Mid-Block chokers are often used with pedestrian crossing treatments.
• Curb extensions should not extend into bicycle lanes, where present.
• Curb extensions at transit stops enhance service.
• No noise and little emergency service impacts.
• May require landscape maintenance to preserve sight distances.
Costs:
• $10,000 to $20,000 each.
29
®RN
7/7-
Choker
Level 2
Description: Chokers are mid-
block curb extensions that narrow
a street by extending the sidewalk
or widening the planting strip. The
remaining cross-section can consist
of one lane (for one way streets)
or two narrow lanes.
Application: Chokers are
1
intended to reduce traffic volumes
and speeds by narrowing the
roadway and making it
uncomfortable to drive above the
desired speed. __- - -- - -- --
Advantages: Disadvantages:
+Effectively reduces vehicle speeds. -Can require removal of parking.
+Shorter pedestrian crossing. -May create hazard for bicyclists.
+Provides improved sight distance. -Can create drainage issues.
+Opportunity for landscaping. -May impede truck movements.
Special Consideration:
• Chokers can be designed with protected bike lane next to original curb.
• Chokers with exclusive bike lanes can collect debris in bike lane.
• Can impact driveway access.
• Also reduce travel speeds when cross-section reduced substantially.
• Preferred by many emergency response agencies to other measures.
• Provide excellent opportunities for landscaping.
Costs:
• $10,000 each.
30
0"i-ot4t
Y/T3/
Speed Hump
Level 2
Description: Speed humps
are asphalt mounds constructed
on residential streets. They are
usually placed in a series and
spaced 300 to 600 feet apart.
Speed humps are typically 12'-20'
feet long and no more than 3
inches high. The vertical
deflection of the hump is
designed to encourage motorists
to reduce their speed.
Application: The primary
benefit of speed humps is speed
reduction. They work well in
conjunction with curb extensions.
Advantages: Disadvantages:
+Effectively reduces vehicle speeds. -Slows emergency vehicles.
+Does not require parking removal. -Increases noise near speed humps.
+Can reduce vehicular volumes. -May divert traffic to parallel streets.
+Easily tested on temporary basis. -Not aesthetically pleasing.
-Difficult to construct without the proper
tools.
Special Considerations:
• Vehicle speeds between humps have been shown to decrease by up to 25%.
• Volumes may decrease if parallel route, without measures, is available.
• Possible increase in traffic noise from braking and accelerating.
• Highest noise increase from buses and trucks.
• Speed humps reduce emergency vehicle response times.
• 3-5 second delay per hump for fire trucks, 10 seconds for ambulances.
• Speed humps require advance-warning signs and object markers at hump.
• Difficult to construct precisely, unless pre-fabricated.
Cost:
• $5,000 each.
31
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Speed Cushions
Level 2
Description: A speed
H
cushion is typically a _-
rectangular section of
pavement that is raised no
more than 3 inches high.
Speed cushions are placed
across the travel way with
a 2-foot space between
each cushion. The 2-foot
space allows for
commercial vehicles to
traverse the humps without having to actually running over the cushion.This reduces noise
created by large vehicles. Speed cushion sites are generally placed 300-600 feet along the
roadway. Their vertical deflection encourages passenger vehicles to reduce speed.
Application: The primary benefit of speed cushions is speed reduction without
excessive noise generally created by commercial vehicles.
Advantages: Disadvantages:
+Effectively reduces vehicle speeds. -Slows emergency vehicles.
+Does not require parking removal. -Increases noise near speed cushions.
+Can reduce vehicular volumes. -May divert traffic to parallel streets.
+Easily tested on temporary basis. -Not aesthetically pleasing.
+Preformed units are available and are
easy to install.
Special Considerations:
• Vehicle speeds between locations have been shown to decrease by up to 25%.
• Volumes may decrease if parallel route, without measures, is available.
• Possible increase in traffic noise from braking and accelerating.
• Highest noise generators like buses and trucks do not generate as much noise as
with speed humps.
• Speed cushions reduce emergency vehicle response times.
• Speed cushions require advance-warning signs and object markers at cushion
location.
• Difficult to construct precisely, unless pre-fabricated.
Cost:
• Varies based on street width, but average residential street cost is $3,000 each.
32
d wMa
Raised Crosswalk
Level 2
Description: Raised
crosswalks are crosswalks
constructed 3 to 4 inches above
the elevation of the street. They
are usually about 22 feet long,
with a flat section in the middle
and ramps on the ends.
Sometimes the flat portion is
constructed with brick or other
textured materials.
Application: Raised
crosswalks are intended to
reduce vehicle speeds specifically
where a high amount of
pedestrians cross the street.
Advantages: Disadvantages:
+Effectively reduces vehicle speeds. -May generate increased noise.
+Good pedestrian safety treatment. -Can require drainage modifications.
+Does not affect access. -Only 3 seconds delay for fire trucks.
+Flat portion can be textured. -Often require signage and markings.
- If crosswalk location is new, there maybe a
Special Considerations: loss of parking.
• Raised crosswalks are usually 22 feet long, with a 10-foot wide flat section.
• Lower elevation than sidewalk to alert visually impaired it=s a crosswalk.
• Careful design is needed due to potential drainage issues.
• Usually preferred by Fire Departments over standard speed hump.
• Work well in combination with curb extensions and curb radius reductions.
• Doe not affect access.
• Increases pedestrian visibility and likelihood that driver yields to pedestrian.
• Often referred to as speed tables or speed platforms.
Costs:
• $5,000 to $10,000 each.
33
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: :
Raised Intersection
Level 2
Description: A raised
intersection is a flat, raised area `
covering an entire intersection.
There are ramps on all ;
approaches. The plateau is
usually about 4" high. Usually,
the raised intersection is
finished in brick or other
textured materials.
Application: Raised `
intersections are used to reduce W'
through movement speeds and t
provide
eisafer street crossings for
pedestrians.
Advantages: Disadvantages:
+Effectively reduces vehicle speeds. -Expensive to construct and maintain.
+Good pedestrian safety treatment. -Requires drainage modifications.
+Can be aesthetically pleasing. -Affects emergency vehicle response.
+Does not affect access. -May require bollards to define corners.
Special Considerations:
• Raised intersections usually used in urban areas.
• Make entire intersections more pedestrian-friendly.
• Work well with curb extensions and textured crosswalks.
• Often part of an area wide traffic calming scheme involving both streets.
• Expensive.
• Special signing often required.
Costs:
• $25,000 to $50,000 each.
34
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Traffic Circle
Level 2
Description: Traffic circles
are raised circular islands in an
intersection. They are typically
landscaped with ground cover
and/or street trees. Traffic circles
require drivers to slow down to a
speed that allows them to
comfortably maneuver around the
circle in a counterclockwise ,, L
direction.
Application: The primary
benefit of traffic circles is speed
reduction and reduction of traffic
collisions.
Advantages: Disadvantages:
+Effectively reduces vehicle speeds. -Parking removal required.
+Reduces collision potential. -Can increase bike/auto conflicts.
+Provides better side-street access. -Can impede emergengr vehicles.
+Opportunity for landscaping. -Can restrict large vehicle access.
Special Considerations:
• Traffic circles are best used in a series or with other devices.
• About 30 feet of curbside parking must be prohibited in advance of circle.
• Buses can maneuver around traffic circles at slow speeds.
• Noise impacts are minimal.
• If well maintained, traffic circles can be attractive.
• Many traffic signs and pavement markings are required.
• Traffic circles are less effective at T-intersections and offset intersections.
Costs:
• $15,000 to $25,000 each.
35
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Intersection Channelization
Level 2
Description: Providing
channelization at three-legged rc
intersections forces previous
straight-through movements to
make slower turning
maneuvers. Channelization is 'k
usually raised.
Application: The primary
benefit of realigning
intersections is speed reduction.
Can also be used to redirect
traffic to another facility or to
provide neighborhood gateway. -
Advantages: Disadvantages:
+Effectively reduces vehicle speeds. -Parking removal required.
+Low impact to emergency services. -May direct traffic to other street(s),
+Can discourage through traffic. -Maintenance responsiUlity.
+Opportunity for landscaping. -Fairly expensive.
Special Considerations:
• Intersection channelization slows traffic down near the intersection.
• Improvement may also discourage some cut-through traffic.
• No significant impedance to fire and transit service.
• Provides landscaping opportunities and potential gateway treatments.
• Can require drainage modifications.
• Possible to vary traffic control with stop signs on one or all three legs.
Costs:
• $15,000 to $20,000 each.
36
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Chicane
Level 2
Description: A chicane is a
series of two or more staggered
curb extensions on alternating
sides of a roadway. Horizontal
deflection influences motorists to
reduce speed through the
serpentine roadway.
Application: The primary "` ..-. w. ,.
benefit of a chicane is speed -
reduction without a significant
impact to emergency vehicle
mobility.
Advantages: Disadvantages:
+Effectively reduces vehicle speeds. - Significant parking loss.
+Low impact on emergency vehicles. -Increased maintenance.
+Opportunity for landscaping. -May require right-of-way.
-Expensive.
Special Consideration: -May restrict resident access.
• A chicane cannot usually be used where right-of-way is limited.
• May require removal of substantial amounts of on-street parking.
• Most effective with equivalent traffic volumes along both approaches.
• May increase conflicts with pedestrians and bicyclists.
• A chicane provides landscaping opportunities.
• Design must consider driveway locations.
• No expected noise impacts.
Cost:
• $20,000 to $40,000 each.
37
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Restricted Movement Barrier
Level 2
Description: Restricted
movement barriers are raised
islands that prevent certain
movements at an intersection.
They are often landscaped.
Application: The primary
benefit of restricted movement <
barriers is to reduce cut-through
traffic levels. They also provide
pedestrian refuge areas for street
crossings.
Advantages: Disadvantages:
+Redirects traffic to other streets. -Redirects traffic to other streets.
+Reduces cut-through traffic. -Will increase trip lengths.
+Provides pedestrian refuge area. -May impact emergency response.
+Opportunity for landscaping. -Creates physical obstruction.
Special Considerations:
• Barriers have a little or no affect on speeds for through vehicles.
• Should not be used on critical emergency response routes.
• Reduces number of potential conflict points for turning vehicles.
• Possibility for landscaping.
• Many variations are possible, including prohibiting turns to/from main street.
• Design needs to consider drainage needs.
• Usually require signing.
Cost:
• $5,000 each.
38
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Entrance Barrier
Level 2
Description: Entrance
barriers are curb extensions or
barriers that restrict movements
into a street. They are ,
constructed to approximately the
center of the street, effectively
obstructing one direction of
traffic. Entrance barriers create a
one-way segment at the -
intersection, while maintaining
two-way traffic for the rest of the
block.
Application: The primary
benefit of entrance barriers is traffic volume reduction.
Advantages: Disadvantages:
+Reduces cut-through traffic. -May divert traffic to other streets.
+More self-enforcing than signs. -Can increase trip lengths.
+Shorter pedestrian crossings. -Potential parking removal.
+Opportunity for landscaping. -Maintenance responsibility.
Special Considerations:
• Restrict movements into street while allowing resident access within block.
• Potential use must consider how residents will gain access.
• In emergency situations, emergency vehicles can gain access.
• But, required maneuver may increase emergency response times.
• Can be provided on opposite intersection corners.
• Bicycles are typically permitted to travel through in both directions.
• Entrance barriers can be nicely landscaped.
• In effect at all times, even when cut-through volumes may be low.
Costs:
• $15,000 to $20,000 each.
39
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Diagonal Diverter
Level 2
Description: Diagonal
diverters are raised areas placed
diagonally across a four-legged
intersection. They prohibit --- -
through movements by creating '
two 'L"shaped intersections.
Application: The primary �,• a
benefit of diagonal diverters is
reduction in traffic volumes. y
These type of diverters also
minimally decrease speeds near
the intersection. -
Advantages: Disadvantages:
+Reduces cut-through traffic. -Redirects traffic to other streets.
+Self-enforcing. -May increase trip lengths.
+Reduces collision potential. -Can impede emergency vehicles.
+Opportunity for landscaping. -Always in effect.
Special Considerations:
• Diagonal diverters can be designed to allow emergency vehicle access.
• Can be designed to allow pedestrian and bicycle access.
• They may shift problems elsewhere unless strategic program developed.
• Provide advantage over complete street closure as circulation is less impacted.
• Can be attractively landscaped.
• Has little or no effect on mid-block speeds.
• Traffic circles are less effective at T-intersections and offset intersections.
Costs:
• $15,000 to $35,000 each.
40
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Street Closure
Level 2
Description: Full street
closures are barriers placed
across a street to completely
close the street to through-
traffic, usually leaving only !,
sidewalks open. They are ! ;
sometimes called cul-de-sacs
or dead-end streets.
Application: Street
closures are intended to
change traffic patterns. They - q
are very effective at reducing
cut-through and general traffic
volumes.
Advantages: Disadvantages:
+Reduces cut-through traffic. -Directs traffic to other streets.
+May reduce local traffic speeds. -Increases trip lengths.
+Self-enforcing. -Affects emergency response time.
+Opportunity for landscaping. -May lose some on-street parking.
Special Considerations:
• Street closures typically only used after other measures have failed.
• Often used in sets to make travel circuitous, typically staggered.
• Require strategic pattern of devices to not shift problem elsewhere.
• Can be placed at an intersection or mid-block.
• Not used on major emergency response routes or transit routes.
• May be designed to allow emergency vehicle access.
• Usually designed with small opening to allow bicyclists and pedestrians.
• Often consist of landscaping.
Costs:
• $20,000 to $35,000 each.
41
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Implementation Process
Community request for action
City's Evaluation of Conditions
"�Action
of
evel I Yes
res?
rk Group Meetingsw problemstify goals
Determine study area
➢ Evaluate Level I options
➢ Recommend measurements
City's Approval of Plan
Prioritize
Neighborhood
Traffic Issues
Reconvene workgroup for
implementation.
Installation of Temporary Measures
Evaluation of Measures
Did the residents
Yes accept the results No
of Measures?
Replace Temporary Consider Removal
Measurements with of Measures
Permanent Ones
Consider other
Neighborhood Measures
Report
42
Community Action Request Form
The purpose of this form is to enable neighborhoods to request the possible initiation of a traffic study in
accordance with the City of Palm Springs'Neighborhood Traffic Calming Policy.The form must be filled out in
its entirety, including a short description of current problems,and signatures of residents and/or property
owners from at least five different residences within the affected area.
After completing this form, please submit it to:
City of Palm Springs
Department of Public Works and Engineering
Traffic Management Center
3200 Tahquitz Canyon Way
Palm Springs,CA 92262
If you have any questions regarding the completion of this form, contact us at Richard]ICalcimalm-
springs.cam or 760-323-8253 ext. 5.
Describe the location where your concerns occur,including the limits of your neighborhood. Provide a map or
sketch of the effected area.
Describe any traffic or safety issues that concern the residents in your neighborhood.Use additional sheets or
the back of this paper if needed.
Provide the names, signatures, addresses and phone numbers of at least five people who concur with the
concerns listed on this form and who reside at different addresses within the effected neighborhood.
Block Captain
Name Signature Address Phone Number
Additional Names Signatures Addresses Phone Numbers
Place additional names if desired on an additional sheet of paper.
Date of Request:
43
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Neighborhood Traffic Calming Program
Prioritization Worksheet
TO BE COMPLETED BY CITY STAFF
City staff, in accordance with the City of Palm Springs Traffic Calming Policy, will
complete this worksheet. It will be used to prioritize the potential use of neighborhood
traffic calming techniques.
Name of Neighborhood:
Traffic Volumes:
Greater than 2000 vehicles per day= 5 points
1,500 — 2,000 vehicles per day = 4 points
1,000 — 1,500 vehicles per day = 3 points
Collision History on Local Streets
More than 5 in one year=8 points
2-4 in one year=4 points
Traffic Speeds
Critical Speed (85th percentile) is 15 mph over speed limit = 6 Points
Critical Speed (85th percentile) is 10 - 14 mph over speed limit = 4 Points
Critical Speed (85th percentile) is 5 — 9 mph over speed limit 2 Points
Critical Speed (85th percentile) is 0 — 4 mph over speed limit = 0 Points
Cut-Through Traffic Levels
(to be measured only if it is the main stated concern of the neighborhood)
Greater than 25% of vehicles are cut-through = 4 Points
15% - 25% of vehicles are cut-through = 2 Points
School & Public Facilities
Each school or facility adjacent to the street=1 point
Neighborhood Impact
Each 500 linear feet of street experiencing the above problems = 1 point
TOTAL SCORE
44
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6. Acknowledgements.
-Mr. Ken Turner
-City of Concord
-Institute of Transportation Engineers
45
Ofmo
MINUTE ORDER NO.
APPROVING AND ADOPTING THE CITY OF PALM
SPRINGS NEIGHBORHOOD TRAFFIC CALMING
PROGRAM
I HEREBY CERTIFY that this Minute Order approving and adopting the City of Palm Springs
Neighborhood Traffic Calming Program, was approved by the City Council of the City of
Palm Springs, California, in a meeting thereof held on the 171h day of July, 2002.
Patricia A. Sanders
City Clerk