HomeMy WebLinkAbout4BCity Council Staff Re{Jorl
DATE: April 22, 2021 UNFINISHED BUSINESS
SUBJECT: REVIEW DESIGN CONCEPT AND PROVIDE DIRECTION ON THE PALM
CANYON DRIVE / INDIAN CANYON DRIVE / CAMINO PAROCELA
TRAFFIC ROUND-ABOUT, CITY PROJECT NO. 20-03.
FROM: Justin Clifton, City Manager
BY: Development Services Department
This a request for the City Council to review the design concept and provide direction to
Staff on how to proceed with the design of the round-about proposed at the intersection
of Palm Canyon Drive/ Indian Canyon Drive, and Camino Parocela, City Project No 20-
03 (the "Project).
RECOMMENDATION:
Provide direction to Staff with respect to the approval of the final concept drawings and
to move forwar~ with the GOnstruction drawings for the Palm Canyon Drive/ Indian Canyon
Drive/ Camirid Parocela Traffic Round-about, City Project No. 20-03.
BUSINESS PRINCIPAL DISCLOSURE:
Not applicable
BACKGROUND:
In 2016, during the conceptual design phase of the Indian Canyon Drive Two-Way
Conversion Project, the City Council requested the 2-way conversion to extend south of
Ramon Road to Camino Parocela.
At the City Council meeting of October 4, 2017, the Council reviewed the conceptual
drawings for the 2-way conversion project, and staff presented for Council's consideration
a traffic round-about concept for the 5-legged intersection of Palm Canyon Drive / Indian
Canyon Drive/ Camino Parocela, shown here:
ITEM NO. 4 E:>
1
City Council Staff Report
April 22, 2020-Page 2
Review and Provide Direction on Indian Canyon/Palm Canyon/Camino Parocela Round-About (CP 20-03)
Albert Webb Associates (Webb) our on-call traffic engineering consultant analyzed traffic
circulation at this intersection in two ways: (1) with a modified traffic signal, and (2) with a
traffic "round-about" design. A copy of the design with a modified traffic signal is included
as Figure 1, and the initial conceptual design of a traffic "round-about" is included as
Figure 2 on the next pages.
2
City Council Staff Report
April 22, 2020-Page 3
Review and Provide Direction on Indian Canyon/Palm Canyon/Camino Parocela Round-About (CP 20-03
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City Council Staff Report
April 22, 2020-Page 4
Review and Provide Direction on Indian Canyon/Palm Canyon/Camino Parocela Round-About (CP 20-03
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City Council Staff Report
April 22, 2020-Page 5
Review and Provide Direction on Indian Canyon/Palm Canyon/Camino Parocela Round-About (CP 20-03
Webb determined that either option will function, however, the traffic "round-about" design
was preferred from a traffic safety perspective in that the rate of traffic accidents at these
types of intersections with a "round-about" are significantly reduced from those with traffic
signal controls.
On June 20, 2018, the City Council reviewed and approved the construction drawings for
the Indian Canyon Drive Two-Way Conversion Project. At that time, staff advised Council
that Webb had further refined the traffic round-about conceptual design, shown as Figure
3 on the next page.
Webb advised that the total cost of the traffic round-about was projected at $2 million
which exceeded available funding. At that time, Council approved the Indian Two-Way
Conversion Project to proceed without the traffic round-about concept, and that if other
budgeted funds became available, staff would proceed with the final design of the traffic
round-about to be constructed as a future project.
On January 30, 2020, The City Council approved a purchase order with Webb for the
development of the final design concept and construction drawings for the Project. The
staff report is included as Attachment 1.
STAFF ANALYSIS:
Webb has reached the first Project milestone by completing the final analysis of the round-
about and providing the Final Design Concept. As part of the effort to analyze the
effectiveness of the round-about and to refine the design, Webb worked with Roundabotix
a design firm that specializes in round-about design. Roundabotix analyzed lane
configurations, round-about layout, truck turning movements, fastest path movements,
entrance angles, natural path and sight distance. The result of Roundabotix analysis
resulted in the Conceptual Roundabout Validation Report that is included as Attachment
2.
Webb used the Validation Report provided by Roundabotix to complete the Final Design
Concept and has requested that the City approve the Final Design Concept prior to
moving on with the construction drawings. Staff has reviewed the validation report and
the final concept as shown in Figure 4 and recommends approval of the Final Design
Concept. The current rough order of magnitude costs provided by Webb for the
construction of the round-about is between $2 million and $2.5 million. Webb will have
the ability to produce a more current and accurate cost estimate when the construction
documents are completed.
5
City Council Staff Report
April 22, 2020-Page 6
Review and Provide Direction on Indian Canyon/Palm Canyon/Camino Parocela Round-About (CP 20-03
Figure 3 -Revised Traffic Round-About Concept Design
6
City Council Staff Report
April 22, 2020-Page 7
Review and Provide Direction on Indian Canyon/Palm Canyon/Camino Parocela Round-About (CP 20-03)
Figure 4 -Traffic Round-About Final Design Concept
7
City Council Staff Report
April 22, 2020-Page 8
Review and Provide Direction on Indian Canyon/Palm Canyon/Camino Parocela Round-About (CP 20-03
ENVIRONMENTAL IMPACT:
Section 21084 of the California Public Resources Code requires Guidelines for
Implementation of the California Environmental Quality Act ("CEQA"). The Guidelines are
required to include a list of classes of projects which have been determined not to have
a significant effect on the environment and which are exempt from the provisions of
CEQA. In response to that mandate, the Secretary for Resources identified classes of
projects that do not have a significant effect on the environment, and are declared to be
categorically exempt from the requirement for the preparation of environmental
documents. In accordance with Section 15301 "Existing Facilities," Class 1 projects
consist of the operation, repair, maintenance, permitting, leasing, licensing, or minor
alteration of existing public structures, facilities, mechanical equipment or topographical
features involving negligible or no expansion of use beyond that existing at the time of the
lead agency's determination. Therefore, in accordance with Section 15301 (c), staff has
determined that the Palm Canyon Drive/ Indian Canyon Drive/ Camino Parocela Traffic
Round-About, City Project No. 20-03, is considered categorically exempt from CEQA and
a Notice of Exemption will be prepared and filed with the Riverside County Clerk.
FISCAL IMPACT:
This action does not require any additional funding. At the January 30, 2020, City
Council Meeting the City Council approved a Purchase Order to Webb in the amount of
$236,·17 4 for the completion of the construction docume·nts for the Palm Canyon Drive /
Indian Canyon Drive/ Camino Parocela Traffic Round-About, City Project No. 20-03, from
excess available Measure J Funds.
Following final design, staff will review the construction estimate and present to Measure
J Commission and City Council for consideration of funding through various sources,
including Gas Tax, Measure A, Measure J, or the Capital Fund.
SUBMITTED:
Director of Development Services
Justin ~IC.
City Manager
Attachment:
1. Staff Report 1-30-2020
Marcus L. Ful er, MPA, PLS, PE
Assistant City Manager
2 Conceptual Round-about Validation Report
8
Attachment 1
9
City Council Staff Report
DATE: January 30, 2020 CONSENT CALENDAR
SUBJECT: AUTHORIZE A PURCHASE ORDER IN THE AMOUNT OF $236,174
WITH ALBERT A. WEBB ASSOCIATES, A CALIFORNIA
CORPORATION, FOR CIVIL ENGINEERING DESIGN SERVICES FOR
THE PALM CANYON DRIVE / INOIAN CANYON DRIVE / CAMINO
PAROCELA TRAFFIC ROUND-ABOUT, CITY PROJECT NO. 20-03.
FROM: David H. Ready, City Manager
BY: Marcus L. Fuller, Assistant City Manager/City Engineer
SUMMARY:
Approval of this item will authorize a purchase order in the amount of $236,174 with
Albert A. Webb Associates, a California corporation, for civil engineering design
services associated with the Palm Canyon Drive / Indian Canyon Drive / Camino ·
Parocela Traffic Round-About, City Project No. 20-03.
RECOMMENDATION:
1. Authorize a Purchase Order in the amount of $236,174 with the City's "on-call" civil
engineering firm, Albert A. Webb Associates, a California corporation, pursuant to
Agreement No. 8356, for engineering design services relative to the Palm Canyon
Drive/ Indian Canyon Drive/ Camino Parocela Traffic Round-About, City Project No.
20-03; and
2. Authorize the City Manager to execute all necessary documents.
BUSINESS PRINCIPAL DISCLOSURE:
Albert A. Webb Associates, is a California corporation, whose officers and owners are
Matt Webb, Scott Webb, and Steve Webb. A Public Integrity Disclosure Form is
included as Attachment 1.
BACKGROUND:
In 2016, during the conceptual design phase of the Indian Canyon Drive Two-Way
Conversion Project, the City Council requested the 2-way conversion to extend south of
Ramon Road to Camino Parocela.
ITEM NO ~Sl'ill-f S ' a t ;;:w;z;, t ¼ft Q\
1 10
City Council Staff Report
January 30, 2020-Page 2
Approval of Purchase Order with Webb Associates (CP 20-03)
At the City Council meeting of October 4, 2017, the Council reviewed the conceptual
drawings for the 2-way conversion project, and staff presented for Council's
consideration a traffic round-about concept for the 5-legged intersection of Palm
Canyon Drive/ Indian Canyon Drive/ Camino Parocela, shown here:
Webb analyzed traffic circulation at this intersection in two ways: (1) with a modified
traffic signal, and (2) with a traffic "round-about'' design. A copy of the design with a
modified traffic signal is included as Figure 1, and the initial conceptual design of a
traffic "round-about" is included as Figure 2 on the next pages.
2 11
City Council Staff Report
January 30, 2020-Page 3
Approval of Purchase Order with Webb Associates (CP 20-03)
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City Council Staff Report
January 30, 2020-Page 4
Approval of Purchase Order with Webb Associates (CP 20-03)
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13
City Council Staff Report
January 30, 2020· Page 5
Approval of Purchase Order with Webb Associates (CP 20·03)
Webb determined that either option will function, however, the traffic "round-about"
design was preferred from a traffic safety perspective in that the rate of traffic accidents
at these types of intersections with a "round-about'' are significantly reduced from those
with traffic signal controls. The US Department of Transportation -Federal Highway
Administration published Safety Aspects of Roundabouts, and identifies that a typical
four-legged intersection has 16 crossing (i.e. right-angle) vehicle conflict points, which
are entirely eliminated with a round-about design. It is these crossing vehicle conflict
points that cause the most severe and fatal vehicle accidents due to the high speed and
"T-Bone" accidents that often occur as a vehicle fails to stop at a red light, as opposed
to side-swipe accidents at lowers speeds within a round-about, as demonstrated in this
graphic representation:
A copy of the Safety Aspects of Roundabouts is available online at:
https://safety.fhwa.dot.gov/intersection/innovative/roundabouts/presentations/safetv as
pects/short.pdf
On June 20, 2018, the City Council reviewed and approved the construction drawings
for the Indian Canyon Drive Two-Way Conversion Project. At that time, staff advised
Council that Webb had further refined the traffic round-about conceptual design, shown
as Figure 3 on the next page.
5 14
m
City Council Staff Report
January 30, 2020-Page 6
Approval of Purchase Order with Webb Associates (CP 20-03)
Figure 3 -Revised Traffic Round-About Concept Design
15
City Council Staff Report
January 30, 2020-Page 7
Approval of Purchase Order with Webb Associates (CP 20-03)
Webb advised that the total cost of the traffic round-about was projected at $2 million
which exceeded available funding. At that time, Council approved the Indian Two-Way
Conversion Project to proceed without the traffic round-about concept, and that if other
budgeted funds became available, staff would proceed with the final design of the traffic
round-about to be constructed as a future project.
STAFF ANALYSIS:
The Indian Two-Way Conversion Project is substantially complete, with continuing fine-
tuning and adjustments of the traffic signal timing and coordination. The project
included the modified traffic signal at the Palm Canyon Drive/ Indian Canyon Drive/
Camino Parocela intersection. Traffic flow through this intersection will function, but will
be delayed given the separate traffic signal phasing required for the 5-legged
intersection.
Staff is recommending that Council authorize final design of the traffic round-about
design for this intersection, with an intention of programming construction in the 2020/21
fiscal year.
Webb has provided a proposal to complete the final design of the traffic round-about, for
a not to exceed time and material budget of $236,174. A copy of Webb's proposal is
included as Attachment 2.
ENVIRONMENTAL IMPACT:
Section 21084 of the California Public Resources Code requires Guidelines for
Implementation of the California Environmental Quality Act ("CEQA "). The Guidelines
are required to include a list of classes of projects which have been determined not to
have a significant effect on the environment and which are exempt from the provisions
of CECA. In response to that mandate, the Secretary for Resources identified classes of
projects that do not have a significant effect on the environment, and are declared to be
categorically exempt from the requirement for the preparation of environmental
documents. In accordance with Section 15301 "Existing Facilities,• Class 1 projects
consist of the operation, repair, maintenance, permitting, leasing, licensing, or minor
alteration of existing public structures, facilities, mechanical equipment or topographical
features involving negligible or no expansion of use beyond that existing at the time of
the lead agency's determination. Therefore, in accordance with Section 15301 (c), staff
has determined that the Palm Canyon Drive I Indian Canyon Drive / Camino Parocela
Traffic Round-About, City Project No. 20-03, is considered categorically exempt from
CECA and a Notice of Exemption will be prepared and filed with the Riverside County
Clerk.
7 16
City Council Staff Report
January 30, 2020-Page 8
Approval of Purchase Order with Webb Associates (CP 20-03)
FISCAL IMPACT:
This is a new capital project that requires appropriation of funding. At the December 18,
2019, Measure J Commission meeting, the Measure J Commission reviewed a list of
recommended capital projects for Measure J funding. At that time, the Measure J
Commission recommended to the City Council to appropriate funding for the Palm
Canyon Drive / Indian Canyon Drive / Camino Parocela Traffic Round-About, City
Project No. 20-03, from excess available Measure J Funds. Staff recommends the City
Council approve an appropriation of $300,000 from Measure J Capital Funds from
excess and carry over funds. The current available balance in the Measure J Fund
unscheduled capital project account (261-4500-50000) is $4.3 million.
Following final design, staff will review the construction estimate and present to
Measure J Commission and City Council for consideration of funding through various
sources, including Gas Tax, Measure A, Measure J, or the Capital Fund.
SUBMITTED
fb~P.E., P.L.S.
Assistant City Manager/City Engineer
Attachment:
1. Public Integrity Disclosure Form
2. Webb Proposal
ATTACHMENTS 1 AND 2 REMOVED TO
REDUCE THE SIZE OF THE REPORT. ALL
ATTACHMENTS ARE ON FILE WITH THE
CITY CLERK
8 17
Attachment 2
18
Palm Canyon -Indian Canyon
Roundabout
City of Palm Springs, CA
Conceptual Roundabout
Validation Report
May 2020
Roundabotix
Rachel Price, PE
roundabotix@outlook.com
858-348-7533
19
Project Title:
Owner:
Introduction/
Initial Design
Assumptions
Lane
Configuration
RB Layout
Figure 1
Design Notes
Design Phase (%): Geometrics
Date: Ma 2020
Roundabotix was contracted by Albert A. Webb Associates to provide geometrics
for a roundabout at the at the intersection of Palm Canyon Drive, Indian Canyon
Drive and Camino Parocela. This is a five-leg, multilane roundabout. The
following assumptions were given for the roundabout conceptual designs:
-The approach speed is 40mph or less for all approaches.
-The design must accommodate a California-Legal truck.
-Bus-45 can make straight thru movements without encroaching into
adjacent lane.
The goal of any roundabout design is to provide geometrics where a diverse mix of
users can successfully share the public right-of-way in a safe and efficient manner.
Accommodating the various users through the intersection while providing good
speed control and proper path alignments is imperative for the success of the
project. With these goals in mind, a conceptual roundabout tailored to fit within
the constraints of the project was designed.
The lane configuration for the roundabout is based on 2% annual growth in traffic
volume for twenty years starting with the base project volumes found in the Counts
Unlimited Report for the peak hour traffic, dated 3/7/2020. The design year
volume in the peak-hour is almost 2700 vehicles per hour. It was determined that a
single-lane roundabout would not adequately handle these design-year peak-hour
traffic volumes. A multilane roundabout that tied into the existing roadway
configuration was accepted. In this configuration the roundabout is multilane
entering and exiting on southbound Palm Canyon Drive, and entering on
northbound Palm Canyon Drive to the exit on northbound Indian Canyon Drive.
All other entrances and exits are single lane.
The traffic analysis can be seen in Appendix A.
To accommodate the existing right-of-way constraints and five legs, the multilane
roundabout does not have a constant inscribed circle diameter (ICD). The
Palm Canyon -Indian Canyon Roundabout
City of Palm Springs, CA 20
Truck Turning
Movements
Figure 2-5
horizontal geometrics of this roundabout can be seen in Figure 1, and the red
numbers on that figure correspond to the numbered bullets below:
1. The outside circulating lane is a wider lane to minimize the potential of
path overlap on the entrance and accommodate a bus in this outside lane.
2. Driveway from parking lot has been revised to avoid pedestrian crossing.
3. Parking that does not interfere with sight distance triangles can remain on
the west leg.
4. It is recommended that a Rectangular Red Flashing Beacon (RRFB) be
used on the crosswalk at the multilane entrances and exits of this
intersection. At this location, it was determined that a zig-zag pedestrian
crossing in the splitter island to push the ped crossing of the exit leg further
away from the ICD was not ideal due to driveway constraints and an
already elongated exit from the oval shape.
5. The driveway on the south leg should be right in/right out.
6. The splitter island could be mountable in front of the driveway on the east
leg to allow for full access if necessary.
7. Upstream of the roundabout on southbound Palm Canyon Drive, the lane
will become right-tum only into a parking facility.
8. Ramps will be provided to connect to existing shoulders and provide access
to shared use path for bicyclists.
The design vehicle movements, California-Legal Truck, were calculated with 6-in
tire clearance to all mountable curbs, 0-in tire clearance to all truck apron curbs,
and 0-in tire clearance to all gutters (which gives a 2.0-ft buffer to the face of curb).
Due to the conservative nature of AutotumTM, these offsets will ensure the design
vehicle will easily be accommodated in the intersection. It is recommended that
truck-friendly curbs be used in the construction of the splitter islands, outside
curbs, and of course truck apron within the limits of the roundabout.
The roundabouts have been designed for trucks to claim both lanes on the
multilane entrances and through the entirety of the intersection. With this design,
the speeds through the roundabout can be minimized, and pedestrian crossing
distances can be minimized which increases the safety at the intersections.
There is no need to have trucks stay in their own lane for this project. In general,
truck drivers prefer to claim the lane on the entrance of the roundabout, in order to
ensure there are no pinched vehicles in the circulating lane. When appropriate,
designing the roundabout with trucks claiming both lanes on the entrance is the
safest type of design for truck traffic, vehicle traffic, and pedestrian/bicycle traffic.
Palm Canyon -Indian Canyon Roundabout
City of Palm Springs, CA 21
Fastest Path
Movements
Figure 6-8
Entrance Angles
Figure 9
The roundabouts have been designed for a Bus-45 to stay in the outside lane as
they navigate northbound and southbound through the intersection.
To calculate the fastest paths of entrance, circulating, and right-turning movements,
the method developed by Ada County Highway District was used. The method
was created to be objective, repeatable, conform to the current FHW A Roundabout
Guide and to reflect anticipated driver behavior/vehicle performance.
Because of the complexity of this roundabout. The circulating radii for
northbound/southbound movements is based on the oval of the circulating lane.
The radii of the oval circulating path is more than 80ft long, or more than 4 car
lengths, which is adequate to influence circulating drivers.
The speeds between conflicting movements are within the proposed guidelines of
NCHRP 672, of 12mph or less.
Multilane entrance speeds were calculated to be 25mph, and single-lane entrance
speeds were calculated to be 22mph or under. All exiting speeds were calculated
to be under 30mph at crosswalk locations, based on an influence of the roundabout
intersection and an acceleration the distance to the crosswalk location. These
speeds indicate a safe design for all users of the intersection.
A check on the entrance angle of each approach was conducted. The method used
to determine the entry angle is conservative, as it is taken at the yield line and uses
the full travel length calculated for the intersection sight distance. In addition, the
critical headway is 5.0sec which adds another factor of safety into the calculation.
A final factor of safety is provided by using the fastest path speeds rather than in
lane speeds or intersection design speeds. With that in mind, not every leg was
able to achieve the 75 degrees at the yield line. However, setting this angle at the
crosswalk ( after the drivers have successfully determined any potential ped/bike
conflicts), a 75 degree angle between the entering traffic and adjacent upstream
approach was achieved. It should be noted that this is still conservative, as the
driver actually begins to look for the upstream potential conflicting path 50ft from
the yield line. As stated in NCHRP 672, in complex roundabouts such as this one,
the engineer must balance not only the entry angle, but also entry path speeds,
potential for path overlap, right-of-way constraints, and sight distance. By
achieving an entrance angle of 75degrees at the crosswalk location, this delicate
balance has been achieved without adversely affecting drivers ability to determine
yield behavior.
Palm Canyon -Indian Canyon Roundabout
City of Palm Springs, CA
April 2020
22
Natural Path
Figure 10
Sight Distance
Figure 11-13
The southbound Palm Canyon Drive and southbound Indian Canyon Drive
entrances are relatively close together. By elongating the oval, the distance
between these entrances would increase, however, the sight distance triangles
necessary would begin to be impeded by buildings, etc. In addition, circulating
speeds would increase and disturb the careful balance of speeds through the
intersection. The entrances were designed to ensure at least two car lengths exist
between yield lines of southbound Indian Canyon Drive southbound Palm Canyon
Drive.
To check the natural path for the multilane entrances, the method developed by the
State of Wisconsin was used. This method predicts the possibility of path-overlap
occurring in multilane designs. In addition, the length of the entrance curve into
the roundabout was measured to be at least 70ft for all multilane entrances which is
a good indication that the curvature of the entrance is dictating proper path
alignment.
Sight distance triangles were calculated based on fastest path speeds rather than
design speeds of the intersection. This is a conservative approach. The stopping
sight distance was calculated for circulating vehicles as well as approaching
vehicles.
The pedestrian sight distance triangles included the ramps of the crossing. The
right-tum pedestrian sight distance triangles was taken from the crosswalk rather
than at the yield line if it gave a more conservative approach.
Based on the fastest path speeds for this design, the sight distance triangles are
achievable and nothing is blocked from adjacent buildings.
Palm Canyon-Indian Canyon Roundabout
City of Palm Springs, CA
April 2020
23
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City of Palm Springs V May 2020 24
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City of Palm Springs V May 2020 25
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City of Palm Springs V May 2020 26
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City of Palm Springs V May 2020
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City of Palm Springs V May 2020 28
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Westbound
Palm Canyon/Indian Canyon RB -Speed Curves ,.._... Figure 6
City of Palm Springs ~ May 2020 29
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Southbound (Palm Canyon)
Palm Canyon/Indian Canyon RB-Speed Curves ""Figure 7
City of Palm Springs V May 2020 30
-R1-95FT, 20MPH
-R2-75FT, 18MPH
-D3-25FT, 23MPH*
-R4-52FT, 15MPH
-R5-120FT, 22MPH
* R2 Speed+Acceleration(Distance to Xwalk)
0
Southbound 2 (Indian Canyon)
Fastest Path Analysis
Palm Canyon/Indian Canyon
Ma 7 2020 y '
Southbound (Palm Northbound Westbound Eastbound Canyon)
R1
R2
R3*
R4
RS
Radius (ft) Speed Radius (ft) Speed Radius (ft) Speed Radius (ft) (mph) (mph) (mph)
169 25 139 23 113 21 106
155 22 155 22 / 72 17 90
-26 -26 -21 -
52 15 53 15 53 15 52
76 18 70 18 106 21 147
* R3 speed= lesser of [speed-radius table value] or [R2+Acceleration*Distance to Crosswalk]
+2% superelevation assumed for R1, R3, and R5 movements
-2% superelevation assumed for R2 and R4 movements
Calculated R3 Speed from Acceleration and Distance from ICD to Leading Edge of Crosswalk
FHWA Acceleration 6.9 ft/sec 2 NCHRP Report sn
Beginning Dist. from Approx. Speed Exiting R2 Speed ICD to (R2) Speed (ft/s) Crosswalk Travel Time Increase (R3) Speed
(mph) (ft) (sec) (mph) (mph)
Southbound 22 32 25 0.8 4 26
Northbound 22 32 27 0.8 4 26
Westbound 17 24 22 0.9 4 21
Eastbound 18 26 23 0.9 4 22
Southbound2 18 27 25 0.9 4 23
Speed
(mph)
21
18
22
15
24
N.T.S.
Southbound2 (Indian
Canyon)
Radius (ft) Speed
(mph)
95 20
75 18
-23
52 15
120 22
IIIIIB1m
9091 W Woodglade Lane
llilt, D 83714
..., rtt+m
Palm Canyon/Indian Canyon RB -Speed Curves ,--. Figure 8
City of Palm Springs V May 2020 31
i
Intersection Sight Distance (ISD) S= 1.468*\/"5.0 ! I
·1
.. ---~ .... -·· -__ ,...,,_..... ----
.
'
Southbound
(Palm Canyon)
Northbound
Eastbound
Westbound
Southbound 2
(Indian Canyon)
\ ', \,.,
.. '· \'·........ .. '\.
.., .. r"•,..".,,,-••-~-.,.,.•
.,. . .... . ""~---~--.. .. ..... .. . ., ... -.,. ,.
IIIDIIII
9091 W Woodglade lane
IIDllt, II 11714
..... 115 ::-
; \ I t
I {
' ' '
', j
Adjacent R1
~t--. ,,
Speed
(mph)
~~~
"-.,.
20
21
25
23
21
"-¾~.
'•',,"'-1;<,,,,,
{
\. \
\,,
,,
\
I
Average S1 -Entering S2 -Circulating
Adjacent R2 Adjacent Circulating Intersection Intersection
Speed (mph) Entering Stream Speed Sight Distance Sight Distance (mph) Speed (mph) (ft) (ft)
18 19 15 139 110
18 20 15 143 110
22 24 15 172 110
22 23 15 165 110
17 19 15 139 110
u I
-Entering ISO
-Circulating ISO
··~.
·---·1
.;: :;;:: ....... -:::. :: ;.,::.
N.T.S.
Palm Canyon/Indian Canyon RB -Entrance Angles ,._,. Figure 9
City of Palm Springs V May 2020 32
Wisconsin Design Manual
LOCATION MINIMUM DESIRABLE
NBA -26 FT 40-50 FT
SBA -26 FT 40-50 FT
-9091 W Woodglade Lane
llaill,1111114
...._ 115::e
N.T.S.
I
MEASURED
50 FT
45 FT
Palm Canyon/Indian Canyon RB -Natural Path Check ~ Figure 10
City of Palm Springs V May 2020 33
Stopping Sight Distance (SSD)
Southbound
(Palm Canyon)
Southbound
(Indian Canyon)
Northbound
Eastbound
Westbound
_, .. , -~, .. -~, .. -+, -,. __ --! I
Circulating
\
(
Posted
Speed Limit
(mph)
40
40
40
20
25
Circulating
Speed
m h
15
D= =•=•= =CJ===C)::::::::, u
-Approach SSD
-Circulating SSD
d= 1.468*2.5"V+1.087V/11.2
R1 Speed
(mph)
25
20
23
21
21
Circulating
Stopping Sight
Distance ft
77
Average
Approach
Speed (mph)
33
30
32
21
23
Approach
Stopping
Sight
Distance (ft)
222
197
212
116
136
L
\' \ \
' \ \ \ \
'\ \ \
I
\. .
\
\' '\. /
'\
r
6
Stopping Sight Distance (SSD)
L
N.T.S.
-9091 I Woodglade Lane
llailt,D 11714
Palm Canyon/Indian Canyon RB -Sight Distance Triangles ~ Figure 11
City of Palm Springs V May 2020 34
Stopping Sight Distance (SSD) d= 1.468*2.5*V+1.087*\/J-/11.2
---, ..... ,--•~-t-
Posted Average Approach
;
Speed Limit R1 Speed Approach Stopping
(mph) (mph) Speed (mph) Sight
Distance (ft)
Southbound -.. ·-~-•;
(Palm Canyon) 40 25 33 222
!
Southbound
(Indian Canyon) 40 20 30 197 • i
Northbound 40 23 32 212
Eastbound 20 21 21 116
Westbound 25 21 23 136
L
L
=•= =•=•= ===D=D==G
\
-Ped Approach SSD
N.T.S.
Pedestrian Sight Distance -9111 I Woodglade Lane
llailt,D 11714
Palm Canyon/Indian Canyon RB -Sight Distance Triangles ,._., Figure 12
City of Palm Springs V May 2020 35
Intersection Sight Distance (ISO) S= 1.468*\/"5.0
Adjacent R1
Speed
(mph)
Southbound
(Palm Canyon) 20
Northbound 21
Eastbound 25
Westbound 23
Southbound 2
(Indian Canyon) 21
'·,, ~: ~ .,
'-.. ··,,
' \
l t
'' _,.. -~ ...... --
.. ~# ;..t
( j''
f
l
;
\,_ !
\
'·
D==•=D==U
-Entering ISD
-Circulating ISD
Average
Adjacent R2 Adjacent
Speed (mph) Entering
Speed (mph)
18 19
18 20
22 24
22 23
17 19
6
Circulating
Stream Speed
(mph)
15
15
15
15
15
S1 -Entering
Intersection
Sight Distance
(ft)
139
143
172
165
139
D
D
•
Intersection Sight Distance (ISD)
S2 -Circulating
Intersection
Sight Distance
(ft)
110
110
110
110
110
C)
N.T.S.
IIUD8III
9091 I Woodglade lane
.... 13714 ·--•~t& ...
Palm Canyon/Indian Canyon RB -Sight Distance Triangles "' Figure 13
City of Palm Springs V May 2020 36
Appendix A
Palm Canyon -Indian Canyon Roundabout
City of Palm Springs, CA
April 2020
37
Rachel Price
3960 W Point Loma Blvd H102
San Diego, CA 92110
roundabotix@ouHook.com
MEMORANDUM
To:
From:
Date:
Project:
Subject:
Eugene Abrego
Albert A. Webb Associates
3788 McCray Street
Riverside, CA 92506
Rachel Price
03-23-2020
Palm Canyon and Indian Canyon Roundabout
Roundabout Traffic Analysis
Introduction
Rachel Price was contracted by Albert A. Webb Associates to provide a conceptual
development of a roundabout at the intersection of Palm Canyon Drive and Indian
Canyon Drive. The AM peak. hour, the mid-day peak hour, the PM peak hour, and the
Saturday peak hour were recorded. The existing traffic counts taken on 3-04-2020 and 3-
07-2020 and were used to verify the lane configuration, see Appendix A.
General Traffic Patterns Observed
The majority of the traffic is going northbound (Palm Canyon Drive to Indian Canyon
Drive) and southbound (Palm Canyon Drive to Palm Canyon Drive) through the
intersection. The Saturday peak hour volumes are the highest for every leg of this
intersection, and follows this general traffic pattern, see Figure 1.
1
38
Indian Canyon Drive
Out In Total
DQfil 200 I 10021
0
Hard
Right
~
10
Left
4
Peak Hour Data
i
North
Peak Hour Begin& at 11 :30 A
Figure I: Saturday Peak Hour Volumes
Lane Configuration Recommendations
u
:::rN _.,..
A single lane roundabout will handle the existing volume of traffic for the
Saturday Peak Hour. However, when an estimated growth rate of2% per year is
applied, this single lane roundabout reaches capacity before 10 years of operation.
Therefore, a multilane roundabout was evaluated with two northbound lanes and
two southbound lanes through the roundabout, see Figure 2.
2
39
camlno Parocel11 WB
H
I I ~
I I ~
0
C
I I i ~
E
f
Ill
Figure 2: Recommended Lane Configuration
The estimated 2% growth rate was applied for a 20-year design life , and the
multilane configuration has enough capacity to handle these projected volumes,
see Figure 3. The extra capacity can be seen in the degree of saturation ratio
volume/capacity (v/c). Typically, if the v/c ratio is above 0.85 the roundabout is
approaching full capacity. In this case the highest v/c ratio is 0.533 which shows
there is room for future growth.
3
40
0.533 10.8 LOSB 4.2 106.5 0.56 0.59 0.56 22.8 1
8 T1 1150 2.0 0.533 5.8 LOSA 4.3 108.3 0.55 0.58 0.55 30.4
18 R2 79 2.0 <?-.?_33 ?·7 LO~A 4.~ !08,~ o.~ 0.5~ q_.-54 25.~ I
Approach 1286 2.0 0.533 6.0 LOSA 4.3 108.3 0.55 0.58 0.55 29.8
East: Camino Parocela WB I
1 L2 59 2.0 0.299 10.6 LOSB 1.2 30.8 0.70 0.84 0.74 21.2 1
6 T1 46 2.0 0.299 6.2 LOSA 1.2 30.8 0.70 0.84 0.74 18.6
16 R2 39 2.0 0.299 6.9 LOSA 1.2 30.8 0.70 0.84 0.74 19.0
Approach 143 2.0 0.299 8.2 LOSA 1.2 30.8 0.70 0.84 0.74 19.9
North: Indian Canyon Drive SB
7 L2 16 2.0 0.307 10.3 LOSB 1.8 44.5 0.40 0.53 0.40 20.5
4 T1 282 2.0 0.307 5.5 LOSA 1.8 44.5 0.40 0.53 0.40 31.0
14 R2 26 2.0 0.307 5.3 LOSA 1.8 44.5 0.40 0.53 0.40 21.8
I Approach 324 2.0 0.307 5.7 LOSA 1.8 44.5 0.40 0.53 0.40 29.8
NorthWest: S Palm Canyon Drive SB
7bx L3 1 2.0 0.506 14.4 LOSB 3.8 96.6 0.73 0.80 0.79 29.1 I
7ax L1 57 2.0 0.506 12.4 LOSB 3.8 96.6 0.73 0.80 0.79 18.9
14ax R1 825 2.0 0.506 7.7 LOSA 3.9 98.0 0.72 0.78 0.77 29.3 1
14bx R3 105 2.0 0.506 7.9 LOSA 3.9 98.0 0.72 0.76 0.76 20.4
Approach 988 2.0 0.506 8.0 LOSA 3.9 98.0 0.72 0.78 0.77 27.8
West: Camino Parocela EB
5 L2 107 2.0 0.355 11.4 LOSB 1.6 40.7 0.73 0.90 0.81 20.2 I
2 T1 17 2.0 0.355 6.9 LOSA 1.6 40.7 0.73 0.90 0.81 17.4
12 R2 42 2.0 0.355 7.8 LOSA 1.6 40.7 0.73 0.90 0.81 19.0
Approach 166 2.0 0.355 10.0 LOSB 1.6 40.7 0.73 0.90 0.81 19.6
I
All Vehicles 2908 2.0 0.533 7.0 LOSA 4.3 108.3 0.61 0.67 0.63 28.0
Figure 3: 2040 Future Volumes
Conclusion
A lane configuration with two lanes northbound and two lanes southbound through the
roundabout handles the proposed traffic volumes, assuming a growth rate of 2%. The
existing volumes are also served, and by keeping all other entrances to one lane, the
complexity of the roundabout is not overwhelming for the existing traffic volumes. This
lane configuration also aligns with the existing travel lanes entering the intersection.
4
41