HomeMy WebLinkAbout2.b. Dodd/Shannon Parkway Stop SignCity of Rosemount
Executive Summary for Action
COMMITTEE OF THE WHOLE: September 12, 2001
Agenda Item: Stop Sign Request - Dodd/Shannon Agenda Section:
Parkway (CS 4LGJ
Prepared By: Gary Kalstabakken Agenda No:
Chief of Police_
Attachments: WSB Letter " 11 Approved By:
Residents requested that traffic and accident data for the intersection of Dodd Boulevard and Shannon Parkway
be evaluated for the purpose of possibly installing four -way stop signs at the intersection. WSB's traffic
engineer evaluated the data and the detailed recommendations are included in the attached letter. In summary,
the recommendation is to leave the current traffic controls in place and continue to monitor the accident data.
This issue is brought for discussion by Council now that the engineer's report has been received.
An additional traffic control issue will also be discussed with Council concerning Shannon Parkway near
Shannon Park Elementary. Staff is recommending the installation of additional signage in the area of the
school. "School Zone" signs are recommended for posting just north and south of the school ground borders.
The second recommendation is to change the speed limit in the area by posting "30 MPH When Children
Present" signs in the area.
RECOMMENDED ACTION NOTES: No action necessary, discussion only.
'A
WS B
&Associates, Inc. July 30, 2001
Mr. Tom Burt
City Administrator FlEcavEt)
City of Rosemount
2875 145 Street West JUL 3 1 2001
Rosemount, MN 55068
Re: Intersection Review
CITY OF� r
Shannon Parkway at Dodd Boulevard
City of Rosemount Project No. 326
WSB Project No. 1304 -00
Dear Mr. Burt:
As you requested, we have reviewed the intersection of Shannon Parkway and Dodd
Boulevard, just north of CSAH 42, in the City of Rosemount. The current intersection
control consists of stop signs for the Dodd Boulevard approaches and yield signs for the
right turn from Dodd Boulevard to north and south Shannon Parkway. The analysis
included in this letter consisted of reviewing the site distance at the intersection, as well as
the potential need for all -way stop sign control.
Site Distance
The site distance at the intersection was evaluated for each approach. It was found that all
approaches had adequate site distance approaching the intersection. However, the right
turning vehicles on Dodd Boulevard to north and south Shannon Parkway are required to
"look over their shoulder" to see oncoming vehicles. This is due to the skew of the
intersection.
S top Sian Installation
The traffic control at an intersection is critical to the operation of both intersecting
roadways. If incorrect traffic control is installed for the existing traffic condition and
topographic characteristics of the intersection, unnecessary delays and crashes could occur.
The traveling public, especially persons not familiar with the area, typically drive based on
instinct. Drivers subconsciously evaluate. their surroundings to determine if a stop sign or
yield sign should or shouldn't be located on an intersection approach. It is very difficult to
determine what the correct intersection control should be, however, the following factors
should be evaluated when determining intersection control:
1. Traffic conditions
4150 Olson 2. Topographic conditions
3
Memorial Highway . Human factors
Suite 300 Based on these conditions and factors, potential intersection control should be evaluated and
Minneapolis determined. Several techniques have been developed to determine what type of intersection
Minnesota control is warranted at specific locations. The best procedure in evaluating the need and
55422 location of all -way stop sign control can be found in the Minnesota Manual on Uniform
7 63541.4800
"53.541.1700 FAX Minneapolis • St. Cloud • Equal Opportunity Employer F:\ WPWIN \1304 -00 \072301 tb.rtf
Mr. Tom Burt
City of Rosemount
July 30, 2001
Page 2
Traffic Control Devices (MMUTCD), Section 213-5. Based on those warrants, the following
requirements are necessary for stop sign installation:
1. All -Way Stop Sign Control
a. Where traffic signals are warranted and urgently needed, the all -way stop can
be an interim measure; or
b. A crash problem indicating that 5 or more reported crashes of a type
susceptible to correction by an all -way stop sign installation in a 12 -month
period; or
c. Minimum traffic volumes:
i. A total vehicular volume entering the intersection from approaches
must average at least 500 vehicles per hour for any 8 hours of an
average day, and
ii. The combination vehicular and pedestrian volume from the minor
street or highway must average at least 200 units per hour for the
same 8 hours, with an average delay to the minor street vehicular
traffic of at least 30 seconds per vehicle during the maximum hour;
but
iii. When the 85 percent approach speed of the major street traffic
exceeds 40 miles per hour, the requirements can be reduced to 70%
(or 30 vehicles per hour).
The traffic volumes in the corridor are approximately 5,200 vehicles per day on Shannon
Parkway and 1,700 vehicles per day on Dodd Boulevard. Assuming that the eighth highest
hour of the day is typically 5% to 6% of the average daily traffic, this intersection would not
meet the volume requirements for all -way stop sign control. Assuming traffic continues to
grow at its current rate (3% - 4% per year), the intersection would meet the requirements in
approximately 3 to 4 years.
If an all -way stop were installed, this would require all vehicles to stop, thereby creating
delays for vehicles on the Shannon Parkway approaches. An operational analysis was
completed assuming a P.M. peak hour traffic volume of 10% of the average daily traffic.
The analysis concluded that with the existing stop configuration the average vehicle would
wait 8 seconds on Dodd Boulevard. Assuming an all -way stop condition the approach
delays on Dodd Boulevard would increase to approximately 10 seconds per vehicle,
however, the delays to vehicles on Shannon Parkway would increase from 0 to
approximately 12 seconds per vehicle. This would translate to a queue length (back -up of
traffic) of 60 to 70 feet (2 to 3 vehicles) on Shannon Parkway waiting to proceed through the
intersection.
With a large difference between the number of vehicles on Shannon Parkway and Dodd
Boulevard, enforcement may become an issue with the vehicles on Shannon Parkway rolling
through the stop signs or not stopping when no vehicles are present on Dodd Boulevard.
This could cause additional crashes in the intersection.
Since 1996, there have been 17 reported crashes at this intersection, four in 1996, five in
1997, four in 1998, two in 1999, and two in 2000. The crashes are primarily right angle
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Mr. Tom Burt
City of Rosemount
July 30, 2001
Page 3
crashes with vehicles pulling out in front of traffic on Shannon Parkway. The number of
accidents in the year 1997 meets the requirement for all -way stop sign control, however,
only four of the five accidents are of a type susceptible (i.e. right angle or left turn into
oncoming traffic- crashes) to correction by all -way stop signs.
Studies conducted throughout the Country have concluded that installation of stop signs
where not warranted or justified can cause additional crashes and create enforcement
problems for local officials. In addition, studies have concluded that the use of stop signs as
a speed reduction measure does not work. In fact, it has been found that speeds near the
intersection will actually increase.
Based on the traffic review as analysis, it would, therefore, be recommended that:
1) The existing stop signs and yield signs on Dodd Boulevard remain as in place.
2) Signs be installed in advance of the intersection on Shannon Parkway indicating
an intersection ahead.
3) Monitor the crash history to see if the number of crashes at the intersection
increases.
If you have any questions or require any additional information on this analysis or
recommendations, please give me a call at (763) 287 -7183.
Sincerely,
WSB & Associates, Inc.
Charles T. Rickart, P.E.
Associate/ Traffic Operations Engineer
c: Bret Weiss, Interim City Engineer
nm/cs
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