Memorandum
City of Lawrence
Public Works
|
TO: |
Dave L. Corliss, Debbie Van Saun |
|
FROM: |
Chuck Soules |
|
CC: |
Shoeb Uddin, David Woosley |
|
Date: |
April 27, 2007 |
|
RE: |
W. 6th Street Traffic |
Introduction
The intent of this memo is to provide a better understanding of what a traffic study means and what it is not. Several impact studies have been completed along HWY40 / W. 6th Street with specific reference to the proposed Wal-Mart and Bauer Farms developments. Traffic studies are based on scientific data but there is also a judgment component. Traffic engineers develop assumptions based on experience and similar conditions. Traffic studies look at worse case scenario peak hour volumes. We have heard about level of “Service F” and failing intersections. The industry uses these terms for consistency of reporting although they are confusing and often misunderstood by the general public.
Traffic flow along a corridor is measured only at intersections where traffic is typically controlled. Intersections have a particular level of service, i.e. a standard number of seconds that an average vehicle will have as a delay (or wait) until they can move through the intersection. The longer the delay the lower the grade (A-F). A level of service of any grade is the same number of seconds delay in Lawrence as it is in Paola, Kansas City, or Chicago. However, I think it would be agreed that an intersection designated as failing in Lawrence is probably not the same as a failed intersection in Chicago at the peak hour.
Computer models and levels of service are only as good as the assumptions made about projected volumes of traffic, distribution of vehicles through the street network, type of traffic (truck, pedestrian), traffic generators, destination of traffic, street improvement and street network. Finally, an intersection with a designated/average level of service indicates the average amount of time a motorist may wait during a peak hour. In Kansas City this delay may be experienced through the entire peak hour whereas in Lawrence this delay may only last for a quarter of the peak hour.
W. 6th Street/HWY 40 Corridor
West 6th Street improvements were completed in 2005. The improvements included two through east and west bound lanes and provisions for dual left-turn lanes at each intersection (currently one of the lanes is stripped). The intersections are Wakarusa, Congressional, Queens, Stoneridge Drive and George Williams Way. All intersections will be signalized when intersecting streets are constructed. A conduit for signal coordination was installed to each intersection. A median between intersections and acquired/purchased access control the corridor integrity for safety and efficiency. The intersection at Wakarusa and 6th Street also has dedicated right-turn lanes in all directions. The total cost of the project was $14,778,418.12; of this the city contributed $5,499,022.74.
Development
The purpose of this section is to assess the impact of trips (traffic) generated by all existing and future developments along 6th Street from Folks Road to Congressional Drive for the target year 2025 based on approved traffic impact studies.
Two major developments are being proposed in this area, including Wal-Mart and Bauer Farms.
|
Intersection @ 6th Street |
Approximate Current ADT |
2025 |
|
Folks Road |
19,700 |
52,000 |
|
Champion |
-- |
|
|
Wakarusa |
22,000 |
57,000 |
|
Congressional |
-- |
-- |
6th and Wakarusa Drive
In 2025 the intersection at 6th and Wakarusa will have an average delay of 46 seconds during the peak hour. Today this is comparable to the intersections at 23rd and Iowa (average delay of 54 seconds) or 23rd and Louisiana (average delay of 50 seconds). This intersection, as constructed, will operate at an acceptable level and no other improvements are needed.
Wakarusa and Overland Drive
A right-turn lane from northbound Wakarusa to eastbound Overland Drive needs to be constructed to accommodate traffic generated by the developments today. In order to accommodate future 2025 traffic this intersection should be signalized and additional left-turn lanes will be needed.
6th and Congressional Drive
Improvements to this intersection include installation of a traffic signal and the extension of the existing second northbound lane on Congressional Drive to end at the Wal-Mart west drive. These improvements will accommodate 2025 traffic needs.
Overland Drive and Folks Road
No immediate improvements are required with the proposed developments. However, to accommodate 2025 volumes a signal and left-turn lanes will need to be constructed.
6th and Folks Road
Additional left-turning capacity on Folks Road and 6th Street will be needed to accommodate 2025 traffic.
6th and Champion Lane
A westbound right-turn lane onto Champion and signalization of the intersection will accommodate the proposed development and 2025 traffic volumes.
Summary
· Access control needs to be maintained for the integrity/efficiency of the street network.
· The proposed Wal-Mart/Bauer Farm developments will add traffic to the 6th Street corridor.
· The proposed improvements to the intersecting streets and 6th Street can accommodate the development and anticipated 2025 volumes.
· Concurrent with approval of development plans. Improvements to the city’s transportation system will need to be completed. Funding for those improvements should be considered/evaluated.
Please feel free to ask any questions.
Respectfully submitted,
Charles F. Soules, P.E.
Director of Public Works