HomeMy WebLinkAbout7. See-Gwun Avenue Speed HumpsMount
Mount Prospect Public Works Department
INTEROFFICE MEMORANDUM
TO: VILLAGE MANAGER MICHAEL JANONIS
FROM: TRAFFIC ENGINEER
DATE: APRIL 3, 2014
SUBJECT: SEE -GWUN AVENUE TRAFFIC CALMING PROJECT
THE APRIL S, 2014 COMMITTEE -OF- THE -WHOLE MEETING WILL BE AN OPPORTUNITY TO ONCE AGAIN
DISCUSS THE SPEED HUMPS ALONG SEE -GWUN AVENUE. STAFF IS REQUESTING A FINAL DECISION TO
THIS ISSUE. OPTIONS INCLUDE REMOVING THE SPEED HUMPS WITH NO FURTHER ACTION, REPLACING
THE SPEED HUMPS WITH AN ALTERNATE PLAN, OR LEAVING THE SPEED HUMPS IN PLACE. THIS
MEMORANDUM PROVIDES A BRIEF HISTORY OF THE ISSUE AND A RECOMMENDATION OF THE LATEST
ALTERNATE PLAN.
Background
See -Gwun Avenue between Lincoln Street and Golf Road is a north -south collector street near the Mount
Prospect Golf Club and Lincoln Middle School. While designed like most of the local, residential streets in
the neighborhood, it has the only bridge over Weller Creek. As a result, it carries more traffic than a local
street. Between Lincoln Street and Lonnquist Boulevard, the street is 26' wide (back -of -curb to back -of-
curb) with slight curves and a hill on the 700 block. Between Lonnquist Boulevard and Golf Road, the
street is 31' wide (back -of -curb to back -of -curb) and is straight and flat.
In 2002, a resident petition requested that the Village address the high volumes and speeds along See -
Gwun Avenue. During the next few years, a number of traffic studies took place. Improvements that were
made included removing sight obstructions near the intersections, adding Stop signs at Council Trail,
constructing a section of sidewalk along the 700 block to complete the public sidewalk along the west side
of the street, and implementing an aggressive Police enforcement campaign geared at slowing vehicles.
Some residents were still unsatisfied with the results and wanted more done to curb the speeding. In
2005, a group of residents requested that speed humps be installed along the street. At the time, the
Village had just begun to experiment with traffic calming measures but did not have a formal program.
There weren't any streets that had speed humps and the Village Board directed Staff to install a series of
them along See -Gwun Avenue as an experimental project. Construction of seven speed humps took
place in 2006 (Attachment A).
In 2007, a neighborhood meeting was held to discuss the results of a Village post- study. While recorded
speeds were lower, there were a number of negative outcomes including a shift in traffic to adjacent
streets, slower response by emergency vehicles, an increase in noise from braking and accelerating over
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See -Gwun Avenue Traffic Calming Project
April 3, 2014
the humps, and their overall appearance. Among the residents along See -Gwun Avenue, half of them
supported the speed humps while half wanted them removed.
The Village Board agreed that the speed humps ought to be removed primarily based on their negative
effect on emergency vehicle response. However, until an alternate plan could be developed and agreed
upon the speed humps would remain. Over the next few years many discussions took place on a traffic
calming program. And in summer of 2011 one was adopted. At the time, it was agreed that developing
an alternative traffic calming plan along See -Gwun Avenue should follow the process outlined in the
plan.
In 2012, the Engineering Division with the cooperation of the Police Department, Fire Department, and
Public Works Department, developed an alternate plan that adhered to the guidelines in the traffic
calming program (Attachment B). It involved replacing the speed humps with a combination of median
islands, pavement markings and roadway signs. It also involved replacing the roll curb along the 700
block (Lonnquist Boulevard to Council Trail) with barrier curb. The plan, however, was not supported by
the residents and ultimately rejected by the Transportation Safety Commission.
No additional discussion had taken place on the subject until the end of last year. Storm sewer
improvements were made along the 800 and 900 blocks (Golf Road to Lonnquist Boulevard) and the
existing three speed humps were temporarily removed as part of construction. This prompted
comments from residents ranging from "leave them out ", to "put them back in ", to "put more in and
make them taller." Staff plans to reinstall them in -kind this spring unless otherwise directed.
Speed Humps
The speed humps along See -Gwun Avenue were installed at the direction of the Village Board in 2006. A
series of seven, 3" high asphalt speed humps spaced approximately 300' apart were used to slow
vehicles. Prior to installing the speed humps, a traffic study was performed to gather volume and speed
data. North of Lonnquist Boulevard, the average speed was 26 mph and the 85 percentile speed was
30 mph. South of Lonnquist Boulevard, the average speed was 31 mph and the 85 percentile speed
was 36 mph. The posted speed limit on See -Gwun Avenue is 25 mph. Daily volumes were
approximately 1000 vehicles except along the block that has the bridge over Weller Creek. Here, the
daily volume was approximately 2000 vehicles.
Two post- studies were then done after installation of the speed humps. North of Lonnquist Boulevard,
the average speed dropped to 23 mph and the 85 percentile speed was 28 mph. South of Lonnquist
Boulevard, the average speed dropped to 23 mph and the 85 percentile speed was 28 mph. Daily
volumes were approximately 600 vehicles except along the block that has the bridge over Weller Creek.
Here, the daily volume was approximately 1700 vehicles.
The speed humps have had their greatest impact on the 800 and 900 blocks, south of Lonnquist
Boulevard. Speeds have been reduced to make them more typical to surrounding residential streets.
Speeds north of Lonnquist Boulevard have not significantly changed as pre- speed humps speeds were
within range of other neighborhood streets. Overall volumes have reduced, on the magnitude of 40%
on some blocks, displacing vehicles to adjacent streets. Both We -Go Trail and Na -Wa -Ta Avenue have
experienced an increase in traffic volume. With See -Gwun Avenue defined as a collector street, 400
vehicles are now using other routes.
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See -Gwun Avenue Traffic Calming Project
April 3, 2014
The last resident survey was done in 2007. 56% of those that responded favored keeping the speed
humps. This was slightly down from the initial survey before installation of the speed humps. Residents
perceived speeds to be lower but were concerned with delays in emergency response, noise and
aesthetics. Residents on We -Go Trail and Na -Wa -Ta Avenue are displeased with the increase in traffic
on their streets.
Traffic Calming Program
In July 2011, the Residential Traffic Calming Program was adopted by the Village Board. This
comprehensive plan covers a number of aspects of traffic calming including minimum criteria, the
process to consider a ,project, and acceptable types of measures. It was agreed that developing an
alternate traffic calming plan for See -Gwun Avenue should follow the adopted guidelines. For your
reference, the full document is available on the Village website via the "Traffic Calming" quick link.
As mentioned earlier, See -Gwun Avenue is defined as a collector street. As such, there are restrictions
as to the types of traffic calming measures that can be used. The program specifically states "Primary
emergency vehicle response routes and collector streets are not eligible for vertical deflection
measures. This is because it is not only imperative that emergency vehicles not be hindered while
responding to an emergency but just as important that the outcome not result in a significant
redistribution of traffic within a neighborhood." Therefore, speed humps should not be considered as a
traffic calming measure on See -Gwun Avenue.
Another important factor in considering traffic calming measures for See -Gwun Avenue is what blocks
actually qualify. The Village is not going to place traffic calming measures on every street. They are
reserved for those streets that continue to experience high speeds and volumes after more conventional
methods such as signs and police enforcement have not resolved the concerns. It is expected that
traffic calming will be considered on the 5 — 10% of neighborhood streets that have excessive speeds
and volumes compared to typical numbers in the Village.
For a street to qualify for traffic calming measures according to the program, at least one of the criteria
thresholds below must be met:
Speed*
• The average speed is at least 5 mph above the speed limit
• The 85`' percentile speed is at least 9 mph above the speed limit
Volume **
The average daily traffic is at least 1000 vehicles
The peak hour volume is at least 120 vehicles
* the 20 mph school speed limit is to be used along streets adjacent to schools, when applicable signs are in place, and when
enhancing pedestrian safety is a primary goal; in all other cases the standard posted speed limit for the street is to be used
** applies only to collector streets adjacent to high pedestrian generator facilities (schools, churches, parks, etc.) and local streets
Considering the speed and volume data along See -Gwun Avenue before installation of the speed humps,
does the street qualify for traffic calming measures?
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See -Gwun Avenue Traffic Calming Project
April 3, 2014
Pre - existing Traffic Conditions
The recorded average and 85 percentile speeds north of Lonnquist Boulevard before installation of the
speed humps were typical for most neighborhood streets and do not meet the speed criteria. South of
Lonnquist Boulevard, the average and 85 percentile speeds were 6 mph and 11 mph above the posted
speed limit, respectively. This segment of roadway has exceeded the threshold for traffic calming
measures. Here, the focus would be to slow vehicles without displacing them to adjacent streets.
With respect to traffic volume, the criteria have been created to primarily address those local streets
that experience cut through traffic. Most collector streets are exempt since the Village is not looking to
shift traffic from collector streets onto local streets. However, for those collector streets adjacent to a
high pedestrian generator facility, the criteria does apply with the goal to enhance pedestrian safety.
For See -Gwun Avenue, the 600 block in front of the Mount Prospect Golf Club (high pedestrian
generator facility) does exceed the volume threshold.
The Alternate Plan
The two basic types of traffic calming measures are vertical deflections and horizontal deflections.
Speed humps are considered vertical deflections as they force vehicles to slow down by going over
them. As discussed earlier, speed humps are not supported on collector streets like See -Gwun Avenue
per the adopted traffic calming program.
Horizontal deflections force vehicles to slow down by going around them or narrowing the roadway.
This can be done by a variety of measures: traffic circles, chicanes, curb extensions, median islands, etc.
The Engineering Division considered all of these as part of an alternate plan that was presented to the
Transportation Safety Commission in 2012 (Attachment B). The preferred design, a series of 30' long
median islands, was opposed because of the loss of some on- street parking and the high density of boat
owners on the street that may have difficulty pulling in and backing out their boat trailers. The median
islands would be decorative and include a combination of small species trees and grass. The total
estimated cost for this project was $112,000.00 of which $70,000.00 was estimated to replace the curb
along the 700 block. However, the plan was rejected by the Transportation Safety Commission based on
input received at the meeting.
Since then, the Engineering Division has considered less intrusive measures for See -Gwun Avenue.
Measures that would not hinder emergency vehicles or disrupt on- street parking while slowing vehicles
and having an aesthetic element. The latest alternate plan involves replacing the speed humps with a
textured, colored street print (Attachment Q. Approximately 1" of the asphalt would be replaced with a
hot, colored material and stamped with a pattern before cooling. Each area would span the width of the
street and be approximately 30' long. Vehicles would be able to drive over and park on the street prints.
They would add a decorative element to the street and provide a visual queue for vehicles to slow
down. The product is known to last the life of the surrounding asphalt and will not fade over time.
Permanent speed feedback signs installed in the parkway would supplement the street prints to remind
motorists to obey the speed limit. The combination of decorative street prints and speed feedback signs
have been used in other communities with success. The latest plan is supported by the Police
Department, Fire Department and Public Works Department. The total estimated cost for this project is
$230,000.00 of which $70,000.00 is estimated to replace the curb along the 700 block.
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See -Gwun Avenue Traffic Calming Project
April 3, 2014
$180,000.00 has been allocated in the 2014 Village Budget for this project. All future maintenance costs
would be done by the Public Works Department and would be factored in future budgets.
Sidewalk
The 700 block (Lonnquist Boulevard to Council Trail) of See -Gwun Avenue has a 4" tall roll curb with
sidewalk adjacent to it. Residents have complained motorists drive /park on the sidewalk. Relocating
the sidewalk to the right -of -way line would be disruptive to existing trees and landscaping, and hasn't
been supported by residents. Another option is to replace the curb with a barrier curb to discourage
motorists from driving /parking on the sidewalk. The estimated cost to replace 1450' of curb is
$70,000.00. It should be noted there is approximately 17,000' (3.2 miles) of curb in the Village with a
similar situation; roll curb with an adjacent sidewalk. Committing to the sidewalk work on See -Gwun
Avenue may set a precedent for other streets in the future. Replacing all roll curb adjacent to sidewalk
could cost in excess of $800,000.00.
Recommendation
The Engineering Division continues to support the alternate plan presented to the Transportation Safety
Commission in 2012 that included a combination of median islands, pavement markings and roadway
signs. However, to address the residents' concerns from the meeting, the Engineering Division
recommends implementing the latest plan that includes a combination of street print and speed
feedback signs. This project can be accomplished in 2014. To keep the project under budget, it is
recommended the sidewalk work along the 700 block not be included in the scope of work. If replacing
the roll curb with barrier curb is supported by the Village Board, it is recommended this work be done in
2015.
Staff will be in attendance at the April 8, 2014 Committee -of- the -Whole Meeting to present the
background and recommendation, and answer questions from the Village Board.
Matthew P. Lawrie'�.�
I concur with the above recommendation.
Sean P. Dorsey, Director of Public Works
c: Transportation Safety Commission
Attachments: Attachment A: Speed Hump Plan (2006)
Attachment B: Median Island Conceptual Plan (2012)
Attachment C: Street Print & Speed Feedback Sign Conceptual Plan (2014)
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