Department Activity ReportsMEMORANDUM
December 30,1998
To: Glen Neier, City Attorney / Interim City Man
From: Jim Hansz, Director of Public W r -
Subject: Traffic signal improvements
I have just received the attached correspondence from NMT concerning improvements to the
signals in town.
• In phase II of the area wide signal upgrade project there will be protected left turn arrows
added at the intersections listed. We have for some time asked that this be done, and when
questioned by the public we have encouraged them to share their opinions on this with MDT.
It appears to have finally paid off. Phase II improvements may be put to bid this spring, if all
the details can be finalized.
In addition to these left turn arrows, we have been informed that NOT has agreed to
implement coordination of the Idaho lights in the near future. Our signals personnel will
assist in this effort to provide for better timing of the existing lights along Idaho. This can be
done with the existing signal equipment. We understand this may begin in a few weeks.
I believe many on the City Council will be interested to know of this. Please share this
information as soon as possible.
N1AS cR FILE
COPY
Montana Department of Transportation
Helena, Montana 59620-14Q1r
M4YvVh
Memorandum
./�%: James T. Weaver, P.E. ,-
District Administrator -Missoula "�•
From: VO Donald P. Dusek, P.E.
Traffic Engineer
Date: December 21, 1998�'�
Subject: NH-STPP 6799(13) DEC 2 8 1998
Citywide - Signal Upgrade
[Fire Sites - Left Turn Arrow Study) MJNTANA DEPARIM£41
Kalispell CN # A701 0' TRArNATION
Ku.ISFEL t;'.X'i1"
As a result of public comment generated by the news release on this project we conducted an analysis
of the left tum activity at five locations in the community. These locations include three intersections
along Idaho St. (US 2 `P-1I and two along W. Reserve Dr. (S-548). The first three, tied in with Idaho,,
are its intersections with 51" Ave. WN (FAU-6721), 3e° Ave. EN (FAU-6724) and 4" Ave. EN (FAU-
6725). Relative to the remaining two, associated with W. Reserve, we have its intersection with both
LaSalle Rd. (US 2 `P•11 and US 93 (P-5).
In general we found the need for left turn arrows at four of the fire intersections. This would provide
a protected/permitted left turn arrow for only one left turn from the arterial at each location, because
the distribution of left turn traffic was highly directional at each site. The resulting revision would
a left -turn arrow as
LOCATION MOVEMENT needing arrow
• US 2 & W. Reserve ht8 on US 2 turning left
• Idaho & 4°t WB on Idaho turning left
• Idaho & 3'd WS on Idaho turning left
• Idaho & 5" WB_ on Idaho turning left
The field data and analysis provided the reasoning behind the need for these arrows by showing a high
proportion of the subject left turns being made during the clearance intervals. That is a high conflict
period. We found that the only way to improve the situation was through adding the protected
movement. Just modifying the signal timing would not work.
There will be a trade-off in delay and congestion. We will 'identify measures to keep those negatives
to a minimum. in our opinion these changes will result in a net improvement in intersection operation.
It is our recommendation these revisions be carried out with phase it of this traffic -signal -upgrade
project scheduled for the Kalispell communit
With regard to US 93 and W. Reserve Drive, we found that there are sufficient gaps during the green
intervals to effectively provide for left turn traffic from US 93. Left turn traffic is not being forced to use
the clearance intervals. Implementing left turn arrows on US 93 would add to intersection congestion
and increase the rear -end accident potential. Therefore, our recommendation is to maintain the
existing signal phasing at this intersection.
If you have questions or wish to discuss fts in more detail, feel free to contact either JohnQuist or me.
36-DPD:JUQ\TRF M_5site_K1298
cc: C. Peil
R. Morgan
L. Talseth
J..Quist