5.12. SR 08-21-2006
City of Elk River
REQUEST FOR COUNCIL ACTION
Agenda Section Meeting Date
En · eerin Au st 21, 2006
Item Description
School Street/] ackson Avenue Intersection Analysis
Item Number
5.12.
Prepared by
Te Maurer, Ci
Reviewed by
Introduction
This spring, the City Council authorized the analysis of the School Street/] ackson Avenue
. . .
mtersectlon operation.
Discussion
The analysis centered on the improvement to the intersection operation that could be achieved by
adding left turn lanes to the southbound and eastbound legs, which currently do not have left turn
arrows. To facilitate the analysis, turning movement volumes were counted on May 23rd and May
24th from 7 - 9 a.m. and 2 - 6 p.m. As is to be expected, there was a morning peak hour from
7:15 - 8:15 a.m. associated with the beginning of school. The same is true of a p.m. peak from
2:15 - 3:15 p.m. Also, there was a secondaty peak from 4:30 - 5:30 p.m.
As has been previously discussed, adding left turn arrows for southbound and eastbound
movements would require restriping of J ackson Avenue. The proposal would be to restripe
Jackson Avenue from School Street to TH 10 as a three-lane facility with a center left turn lane.
This would serve two putposes; 1) it would add a long left turn lane at School Street for the
morning a.m. school rush, 2) it would add a left turn lane for the proposed Jackson Villa
T ownhome development on the west side of J ackson Avenue. This restriping would require a
restriping of a portion of J ackson Avenue north of School Street to make the geometries work
properly.
The analysis of the existing traffic and future considerations at this intersection indicated that the
restriping and modification to the signal to provide left turn arrows on all four legs would
improve the overall operation of the intersection. The one exception to this, given the current
configuration, was the southbound a.m. peak hour through and right turn lane which would be
combined movements, had a relatively long queue length of 230 feet. Further analysis was done
to determine whether or not the addition of a separate right turn lane for the southbound leg only
would help the situation. The conclusion of this further analysis was a separate right turn lane
approximately 200 feet in length including taper would significantly reduce the queue length for
the southbound traffic in the a.m. peak.
Adding this right turn lane to the southbound leg brings several other issues into play. First,
additional right of way would need to be secured from the School District, since the existing right
of way of J ackson Avenue would not allow sufficient room for adding a right turn lane. Second,
adding the southbound right turn lane would require more significant modifications to the
existing signal system. The signal controller which is located in this quadrant would need to be
relocated. The signal pole in this quadrant would also need to be relocated, along with an
extension to the mast arm.
Financial Impact
Simply adding the left turn arrows to the two remaining legs of the intersection is a relatively
simple modification. The signal mast arms would need to be slightly lengthened and new heads
added to facilitate the left turn arrow. All total, the estimated cost to modify the signal would be
approximately $35,000. In addition, there would be the cost of sealcoating and restriping Jackson
A venue.
The second option which includes adding a right turn lane to the southbound leg of the
intersection would have much more significant impacts to the signal system. In addition to
adding left turn arrows, the controller and the signal pole in the northwest quadrant would need
to be relocated and a more significant extension made to the mast arm. These modifications to
the signal system are estimated to cost approximately $75,000. In addition, more right of way
would need to be secured from the School District. Assuming this could be done at no cost, the
construction of the right turn lane is estimated at an additional $75,000. Therefore, this option,
which would provide for better intersection operation, has a price tag of approximately $150,000
plus the cost of sealcoating and restriping of J ackson Avenue.
Both School Street and J ackson Avenue are eligible for the use of Municipal State Aid funds.
Attachments
. None, however graphics will be available at Monday evening's meeting to further discuss
this issue.
Action Requested
Discussion of the preliminary intersection analysis and direction to staff on how to proceed with
this issue.
Council Action
Motion by _
Second by _
Vote
Follow Up
S:\EngineerImprovProj\2006 Improvement Projects\School St.Jackson Intersection\08 21 06 cc memo.doc