HomeMy WebLinkAbout2019-12-02; Traffic and Mobility Commission; ; REGIONAL TRAFFIC CALMING PRACTICESItem #4
Meeting Date: December 2, 2019
To: Traffic and Mobility Commission
Staff Contact: John Kim, City Traffic Engineer
John.Kim@carlsbadca.gov, 760-602-2757
Subject: Regional Traffic Calming Practices
Recommended Action
Receive an informational presentation providing an overview of traffic calming in the region
including best practices, standards and programs.
Executive Summary
On June 11, 2019, a Minute Motion was proposed by Mayor Pro Tem Bhat-Patel, seconded by
Council Member Hamilton, to perform a comprehensive traffic calming analysis to include what
types of traffic calming measures are currently used in the region, research new approaches to
traffic calming and report what measures are commonly used in the City of Carlsbad. The
Motion carried unanimously 5-0.
On November 19, 2019, staff presented to City Council an information item providing an
overview of traffic calming in the region. A Minute Motion was proposed by Council member
Schumacher, seconded by Mayor Hall, to present this item to the Traffic and Mobility
Commission and to receive their input. The Motion carried unanimously 4-0.
Discussion
The Carlsbad Residential Traffic Management Program (CRTMP) outlines the strategy and
procedures to reduce the negative impacts associated with vehicular traffic by providing traffic
calming on residential streets. The program was developed in 2001 and revised in 2011. The
goals of the CRTMP include:
• Improving quality of life in neighborhoods
• Creating safe streets by reducing collision frequency and severity
• Reducing negative effects of vehicular speeding
• Utilizing features that are self-enforcing.
The CRTMP utilizes three phases to address speeding concerns on residential streets. The
purpose of these three phases is to provide a best value, cost-effective approach by
incrementally increasing the magnitude of applied solutions as needed to achieve the
program’s goals.
Phase I is initiated when a resident contacts the city to express a concern regarding speeding on
their residential street. Transportation staff, in close collaboration with the Police Department,
utilize engineering, education and enforcement efforts to address the concerns.
Phase I focuses on the human element of driver behavior and leverages strategies such as
education of the public, police presence and police enforcement to help reduce speeding. The
engineering tools available in Phase I include speed limit signs, warning signs, pavement
legends and temporary speed feedback signs. The temporary speed feedback signs serve a dual
purpose: collection of speed data and as a speed reduction feature. Phase I solutions are
usually implemented at the staff level and may include work orders for installation of signs and
pavement legends. Depending on availability of temporary speed feedback signs and the type
of work proposed, Phase I can last between four to six months.
If the Phase I solutions do not adequately address the reported issues, Phase II of the CRTMP
can be considered. The threshold for Phase II eligibility is a minimum critical speed of 32 miles
per hour (MPH), determined by using data collected during Phase I. This threshold was set so
that city resources could be most effectively allocated for the highest priority traffic safety
needs. The critical speed, otherwise known as the 85th percentile speed, is the speed at which
85% of the drivers drive at or below. The critical speed, as described in the California Manual on
Uniform Traffic Control Devices (CA MUTCD), represents one standard deviation above the
average speed and is used for speed zoning purposes.
Phase II of the CRTMP is initiated when speed measurements indicate a critical speed of 32
MPH or higher on a residential street. Phase II utilizes cost-effective physical traffic
management devices such as speed cushions and tables, high-visibility crosswalks, narrowing
travel lanes with striping, and neighborhood signs. Please note that although they are included
in the 2011 edition of the CRTMP, stop signs are no longer considered by staff as a viable
recommendation for traffic calming, based on the CA MUTCD guidance that stop signs should
not be used for speed control (Section 2B.04, Paragraph 05). In situations where a traffic
calming feature is desired at an intersection, staff will consider such features as a traffic circle
or speed cushion instead of a stop sign.
Per the CRTMP, consensus support of the community is required before Phase II measures can
be implemented. The first step toward establishing consensus is a neighborhood meeting.
Residents and property owners within the project study area are invited to attend a
neighborhood meeting organized by staff. At the meeting, staff presents traffic calming
strategies and options tailored to their individual street. Input provided by the meeting
attendees is used to develop a preferred concept plan for traffic calming.
A mail survey is used to quantify neighborhood support for the traffic calming plan developed
at the neighborhood meeting. The surveys are sent to all residents and property owners in the
project study area. The CRTMP requires that at least 50% of the mailed surveys be returned to
constitute a valid survey and that a support rate of 67% or more is required to indicate positive
community support for the proposed plan. If these support requirements are satisfied, the
proposed traffic calming plan is brought before the Traffic & Mobility Commission for their
recommendation and then to City Council for project approval. If City Council approves the
traffic calming plan, the project enters the design phase, which will result in a set of
construction plans for implementation. It can take between 6-12 months to complete the Phase
II process. Traffic speeds are measured after Phase II implementation to verify the effectiveness
of the implemented solutions.
If the Phase II solutions do not adequately address the reported issues, residents can request
moving to Phase III of the CRTMP.
Phase III utilizes more expensive physical traffic calming devices that change the character or
nature of an intersection or roadway and includes traditional traffic calming features such as
traffic circles, center island narrowing, curb radius reductions, raised intersections, mid-block
chokers, lateral shift in lanes, chicanes, intersection bulb-outs, realigned intersections, forced
turn channelization, median barriers and traffic diverters.
Eligibility for Phase III is determined using a Phase III Qualification Criteria to be conducted by
staff. The criteria consider such factors as travel speeds, traffic volumes, collision history,
absence of sidewalks, proximity to schools and presence of marked crosswalks, and utilizes a
points assignment system. A minimum score of 51 points is required for candidate streets to be
considered for Phase III.
With the three-phase CRTMP, the city has a comprehensive and efficient strategy to address
speeding issues on residential streets. In 2018, the CRTMP resulted in construction of traffic
calming improvements on Corintia Street, Daisy Avenue, Cadencia Street and Harbor Drive. The
measured critical speeds after implementation (Corintia Street - 29 MPH, Daisy Avenue - 29
MPH, Cadencia Street - 30 MPH and Harbor Drive - 23 MPH) indicate the successful application
of Phase II measures on these streets.
In 2019, the CRTMP process has been active with ten streets currently in the Phase II process
including Amargosa Drive, Basswood Avenue, Hillside Drive, Avenida Diestro, Estrella de Mar
Road, Harwich Drive, Segovia Way, Avenida Pantera, La Golondrina Street, and Cadencia Street
(Lower). Neighborhood meetings for these ten streets have been completed.
Due to the success of Phase II measures, Phase III of the CRTMP has not yet been implemented
on any street in Carlsbad.
Traffic Calming on Non-Residential Streets
In certain situations, traffic calming features may be considered on non-residential streets.
Since most non-residential streets lack single-family homes with direct frontage upon them, it
would be difficult to obtain consensus using the methodology outlined in the CRTMP. Another
consideration is that most of the traffic calming features previously described have been
designed for relatively low speeds and may not be appropriate for higher speed/higher volume
roadways. In the past, staff has implemented traffic calming on non-residential streets on a
case-by-case basis as projects of the CRTMP. Examples of these include the recently completed
project that installed speed feedback signs on Jefferson Street, State Street, Tamarack Avenue,
Alicante Road and El Fuerte Street and the road diets on La Costa Avenue and Avenida Encinas.
Traffic Calming in Other Cities: As part of this report, staff has investigated the following cities
in San Diego County to determine and compare traffic calming practices, methods and features:
• Chula Vista
• Coronado
• Del Mar
• El Cajon
• Encinitas
• Escondido
• Imperial Beach
• La Mesa
• Lemon Grove
• National City
• Oceanside
• Poway
• San Diego
• San Marcos
• Santee
• Solana Beach
• Vista
Table 1: Traffic Calming in the Region
Carlsbad Chula Vista Coronado Del Mar El Cajon Encinitas Escondido Imperial Beach La Mesa Lemon Grove National City Oceanside Poway San Diego San Marcos Santee Solana Beach Vista Established Program
Speed Humps Only
Program is Confirmed Active
Program is Confirmed Inactive
As Table 1 shows, of the 17 cities researched for this report, 10 have formalized traffic calming
programs that can be reviewed and compared. Agencies that have generalized descriptions of
traffic calming on their website without specific recommendations (Chula Vista) and agencies
with limited, speed hump-only policies (Coronado, Del Mar and El Cajon) were not included in
the following analysis. It is interesting to note that three agencies that have established traffic
calming programs in place have informed us that their programs are inactive or suspended (El
Cajon, Oceanside and Vista). The traffic calming programs of the 10 compared agencies are
focused on residential streets with only four agencies (Encinitas, Oceanside, San Diego and
Solana Beach) allowing consideration of traffic calming on arterial roadways.
As described previously, Phase I of the CRTMP utilizes features that are relatively inexpensive
and easy to implement. Table 2 shows these cost-effective features and how they are utilized
regionally.
Table 2: Phase I Features Compared
Carlsbad Encinitas Escondido Imperial Beach La Mesa Lemon Grove Oceanside Poway San Diego Solana Beach Vista Education
Police Enforcement
Regulatory/Warning Sign
Non-Standard Sign
Pavement Legend
Speed Feedback Sign
Neighborhood Monitoring
Looking at these features, we note that Carlsbad does not use non-standard signs. Some
agencies have chosen to deploy signs that are not compliant with the CA MUTCD such as KEEP
KIDS ALIVE DRIVE 25. Although Carlsbad does not support usage of such signs in the public
right-of-way, we do not disallow the use of these signs on private property as long as the sign
complies with the city’s sign ordinance (Carlsbad Municipal Code Chapter 21.41).
The bulk of traffic calming tools that Carlsbad utilizes are found in Phases II and III of the
CRTMP. For comparative purposes, these have been divided into four categories: vertical
deflection measures, horizontal deflection measures, diversion measures and other measures.
Table 3: Vertical Deflection Measures Compared
Carlsbad Encinitas Escondido Imperial Beach La Mesa Lemon Grove Oceanside Poway San Diego Solana Beach Vista Speed Table/Raised X-Walk
Speed Cushion
Raised Intersection
Table 3 shows the variety of measures that use vertical deflection to slow down vehicles. Please
note that there is variation in the design and implementation of vertical deflection measures
for each agency. It would be accurate to state that Carlsbad utilizes the full range of vertical
deflection features that are used regionally.
Table 4: Horizontal Deflection Measures Compared
Carlsbad Encinitas Escondido Imperial Beach La Mesa Lemon Grove Oceanside Poway San Diego Solana Beach Vista Median
Curb Radius Reduction
Traffic Circle
Mid-Block Choker
Lateral Shift
Chicane
Intersection Bulb-out
Re-aligned Intersection
Roundabout
Table 4 shows the different types of horizontal deflection measures that are used regionally for
traffic calming. Although roundabouts are not listed as an available feature in the Carlsbad
program, staff does not consider this an omission since traffic circles can be considered, in the
context of residential streets, as equivalent to roundabouts.
Table 5: Diversion Measures Compared
Carlsbad Encinitas Escondido Imperial Beach La Mesa Lemon Grove Oceanside Poway San Diego Solana Beach Vista Turn Restriction via Sign
Forced Turn Channelization
Median Barrier
Semi-Diverter
Partial Diverter
Diagonal Diverter
Street Closure
Many traffic calming programs, including Carlsbad’s, include features that are more appropriate
for addressing cut-through traffic rather than speed reduction. Table 5 lists the diversion
measures offered in the region. Since speeding has been the primary concern of residents who
have contacted the city and, since all of the diversion measures in the CRTMP reside in Phase
III, no diversion measures have yet been implemented in Carlsbad. The only diversion tool that
is offered regionally, but not in Carlsbad, is street closure.
Table 6: Other Features Compared
Carlsbad Encinitas Escondido Imperial Beach La Mesa Lemon Grove Oceanside Poway San Diego Solana Beach Vista Residential Stop Sign *
High Visibility Crosswalk
Narrowing Lanes/Striping
Neighborhood Warning Sign
Textured Pavement
Entry Treatment
Driveway Link
Woonerf
Pedestrian Hybrid Signal
The last set of features that were compared are those that did not fit the prior categories. Table
6 above shows these miscellaneous features. As previously noted, Carlsbad no longer utilizes
stop signs as a traffic calming tool. There are a couple of interesting features that are specific to
Encinitas only. The Woonerf is described as a public right-of-way space that is shared by
vehicles and people in cars. The Driveway Link converts a two-lane street into a winding one-
way street over a short distance, connecting residential driveways. Escondido offers the
pedestrian hybrid signal as a traffic calming feature in their program. Since the pedestrian
hybrid signal requires consideration of specific factors as described in the CA MUTCD, Carlsbad
chooses to analyze implementation of the pedestrian hybrid signal independent of the CRTMP.
Based on staff’s analysis of traffic calming in the region, the CRTMP can be considered a
complete and efficient program that features a full range of traffic calming measures that
compare favorably with what other agencies are using.
Next Steps
Utilizing the available resources, staff will continue to analyze and consider new and innovative
traffic calming techniques as they become known. Staff will formally remove stop signs from
the program in a future programmatical update to the CRTMP.