White St Pro P H FollowupMEMORANDUM
April 11, 2002
TO:
FROM:
SUBJECT:
The Honorable Mayor and City Council Members
Michael C. Van Milligen, City Manager
White Street Reconstruction Project - Public Hearing Follow-Up
Public Works Director Mike Koch submits the attached memo to provide follow-up
information on several questions left unanswered at the conclusion of the public hearing
on the White Street Reconstruction Project from 21st to 32nd Street.
Michael C. Van Milligen
MCVM/jh
Attachment
cc: Barry Lindahl, Corporation Counsel
Cindy Steinhauser, Assistant City Manager
Michael A. Koch, Public Works Director
CITY OF DUBUQUE, IOWA
MEMORANDUM
April 10, 2002
TO:
FROM:
SUBJECT:
Michael C. Van Milligen, City Manager
Michael A. Koch, Public Works Director
White Street Reconstruction Project - Public Hearing Follow-Up
INTRODUCTION
The public hearing on the White Street Reconstruction Project from 21st to 32nd
Street was held by the City Council on January 21, 2002. Even though the
project was approved, there were several questions left unanswered at the
conclusion of the hearing.
BACKGROUND
The unresolved issues are summarized as follows:
Can White Street be narrowed to 37 feet in width in the 22nd to 24th Street
blocks? This is intended to slow down the perceived excessive speeding
in these blocks.
Can the proposed pavement thickness between 22nd and 24th Streets be
decreased from the proposed 8" thickness to 7" as it the balance of the
project?
Can the advance signage be improved to better direct motorists and
truckers to turn left at 21st Street, which is the marked truck route?
Can the horizontal offset of White Street at 22nd Street be lessened to
improve the traffic flow to motorists crossing 22nd Street at White?
5. Can the City limit the number of trucks on White Street between 21st and
24th Street?
DISCUSSION
1. Street Width
The Engineering Division's review of the plans for paving of the section of
White Street between 22nd and 24th street indicates that there should not
be a problem in narrowing the proposed pavement width from 41' to the
requested 37-foot width.
Traffic volumes in this two-block area were found to be 585 vehicles per
day southbound on White Street and 1,083 vehicles northbound. The 85th
percentile speed, which is the speed normally considered when
performing speed studies, is 25.0 m.p.h, for southbound traffic and 26.6
m.p.h, for northbound traffic. This is consistent with the street's posted 25
m.p.h, speed limit. There were speeds in excess of 25 - 26 m.p.h.;
however, these numbers were small in comparison to the total volume of
traffic on the street. No further action is felt to be necessary to control
traffic speed on White Street between 22nd and 24th Street.
The City's experience on the reconstruction of the City streets is that traffic
speeds do not increase after the completion of a paving project. This has
been documented over several years by performing "before" and "after"
speed studies.
2. Pavement Thickness
The total daily traffic on White Street from 22nd to 24th Street is 1,668.
This is equivalent to a medium volume local residential street. There
should, therefore, be no problem in decreasing the proposed pavement
thickness to 7", which would be consistent with the balance of the project.
3. Signage
The Engineering Division's review of signage did indicate that a couple of
changes were in order. A maP is enclosed showing these changes and
their location.
First, a "No Trucks Over 5 Tons Licensed Weight" sign was installed for
northbound traffic immediately north of 21st Street. (Trucks are prohibited
in this block of White Street unless making local deliveries.) This should
require trucks to either follow the marked truck route over to Central
Avenue or to turn eastbound on 21st to Jackson Street. Qne set of
improperly-placed lane use signs was also removed. An additional "No
Truck" sign will be placed for northbound traffic north of 22nd Street. This
would be identical to the newly-placed sign at 21st Street.
As can be seen on the map, there are already advance signs between 19th
and 20th, and between 20th and 21st Street indicating the proper lane
usage to follow Highway 52 north to Central Avenue. The placement of
these signs was also reviewed by the Iowa Department of Transportation
since this is a marked highway route.
Both IDOT and the City feel that with the changes indicated the signage
should be up-to-date and appropriate for the situation.
The Engineering Division also looked at modifications to the existing
island at the intersection of 21st and White Street to determine if it should
be made larger in order to slow northbound traffic in the 21st to 22nd Street
block and to keep trucks from continuing on White Street north of 21st
Street.
As can be seen on the enclosed photograph, the existing concrete island
is about as large as it can be to safely pass by the median with sufficient
clearance. If the island were enlarged to the east, parking would have to
be removed from the east side of White both north and south of 21st Street
to allow for sufficient clearance. This would, however, defeat the purpose
of the widening of the island, since vehicles would then not be required to
slow down to continue this northbound movement.
Similar to the other section of White Street, the existing 25 m.p.h, speed
limit is appropriate for this block, with vehicles traveling 27.5 m.p.h, for the
85t~ percentile speed northbound and 24.7 m.p.h, southbound.
This flow of traffic northbound past 21st Street appears deliberate
according to the traffic volumes taken in this area. Fifty-five percent (55%)
of this northbound traffic is destined for 22nd Street and does not continue
northerly beyond this point.
4. Horizontal Offset at 22nd Street
The Engineering Division has reviewed the current offset in the curb lines
of White Street from the south side of 22nd to the north side. The reason
for the offset is unclear, but it is clear that even with narrowing of White
Street to 28', the offset cannot be made significantly smoother than it
currently is without the purchase of additional right-of-way. This is
because we are still working on the same right-of-way width of both sides
of 22nd Street and the narrowing of White Street north of 22nd only results
in a total curb offset of 3'.
Attached is a plan of the current configuration of the intersection. The
plans to narrow White Street provide for the east curb to be moved 3'
westerly, creating an offset roadway within the right-of-way. If the
narrowing were to be made equally on both sides of the street, the offset
between the curbs would become even greater. Also attached is a plan
showing the amount of right-of-way which would be needed to align the
centedines of White Street across 22nd Street.
5. Truck Usage
The issue of truck usage was addressed in Paragraph 3.
ACTION TO BE TAKEN
The City Council is requested to review the responses of the City staff to the
issues left outstanding at the conclusion of the public hearing and to give
direction to City staff on how to proceed on the various issues.
MAK/vjd
cc: Michael Felderman, Civil Engineer
Bill Schlickman, Engineering
REFERENCE:
White Street
Average Annual Daily Traffic
1. Street Width
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