Site Overview
The existing store is located within the
Route 159 to the west (a row of outparcels is located between the Plaza and Route 159).
Construction was recently completed by the Illinois Department of Transportation (IDOT) to widen
Route 159 to a five-lane section (two through lanes in each direction plus a center left-turn lane)
adjacent to the site. Route 159 now consists of five lanes from Edwardsville to
(with the exception of downtown
This site currently has good accessibility from the regional road network, and the improvements to
Route 159 have eased congestion on that roadway and further enhanced access for patrons of
opposite Junction Dnve, though the intersection of the Plaza's ring road with Cottonwood Dnve is
also heavily utilized. A traffic signal has recently been installed at that location to serve both the
ring road and a new grocery store on the south side of
In addition, patrons of the site may also access Route 159 via
restricted to right-dright-out only as part of IDOT's widening project) and at its signalized
intersection with
adjacent Lowe's store was constructed. Finally, access to the rear of the site (near the Tire & Lube
Express) is provided via a driveway on
Wal-Mart loading dock in the southeast comer of the building.
It should be noted that both IDOT and the
evaluating potential changes in traffic operations at this site. Specifically, DOT has jurisdiction
over Route 159, while the Village controls
full traffic impact study to specifically analyze the capacity of the external intersections.
Existing Access & Circulation Issues
In general, the availability of multiple points of access to the site provides favorable accessibility to
the existing Wal-Mart from the external roadways. The recent expansion of Route 159 to five lanes
has significantly improved conditions on that roadway and reduced delays associated with accessing
the site from the north, west and south.
In addition, motorists exiting the site onto
experienced lengthy delays during peak periods as well. However, the increased capacity on Route
159 along with the recently installed traffic signal at the ring road intersection have substantially
improved conditions at that location and facilitated improved access tolfrom the east.
Although the site's external access constraints have largely been addressed by these recent
improvements, several issues were identified with regards to the existing Wal-Mart store's internal
circulation and parking. For ease of reference, the areas of concern are identified graphically in
Exhibit 1 and described in detail as follows.
A. Access tolfrom West Ring Road
Access to the existing Wal-Mart parking lot is provided via three drives on the three-lane ring
road between Cottonwood Road and Junction Drive. The northernmost entrance to the lot is
located too close to Junction Drive and the "canoe" diverter for incoming motorists, which
results in frequent conflicts between motorists executing northbound left tums onto Junction
Drive and those making southbound left-tum movements into the site parking lot.
In addition, each of the three driveways on the ring road have substantial sight distance
restrictions due to the presence of bushes along the east side of the road. That vegetation
obstructs the sight lines of motorists attempting to exit the lot and forces drivers to pull slightly
into the roadway in order to view oncoming traffic, which is a significant safety concern.
B. Parking Conflicts
A review of a previous study on parking lot crashes at Cottonwood Plaza and several other area
shopping centers (as part of a University research project) revealed that a total of 60 crashes were
reported within the Cottonwood Plaza parking lot in 2001 alone, and the large majority of these
incidents occurred in fiont of Wal-Mart. During recent observations at the store, numerous
conflicts were observed within the parking lot, including activity near the ring road entrances,
near the rear access drive at the southwest comer of the building and within the parking lot itself.
One contributing factor to these conflicts appears to be that there is currently no contiguous
north-south drive aisle within the parking lot, so motorists must utilize the ring road, cut across
the parking aisles or traverse the fiontage of the store in order to circulate within the parking lot.
Motorists were typically observed doing the latter two alternatives, and the 2001 crash records
included numerous incidents &om vehicles cutting across the lot and hitting another moving or
parked car. The prevalence of these collisions is likely due to the expansive parking lot and the
lack of separation or delineated drive aisles throughout the lot.
C. Access Constraints to Cottonwood Road
At the southern end of the ring road, the activation of the signal on Cottonwood Road has
improved conditions for motorists exiting the site. However, inbound motorists fiom the east are
sometimes c'blocked" by westbound queues at the signal. The proposed installation of a
westbound right-turn lane at this location would significantly improve these conditions.
D. Traffic Flows Between Front and Rear of Store
Although they are apparently intended primarily as truck and Tire & Lube Express entrances and
only for secondary customer access, the two entrances near the southeast comer of the site (one
on Cottonwood Road and one on Kriege Farm Road) are used extensively by customers
accessing the front parking bt. This heavy use is likely due in part to the congestion present at
Cottonwood Road's intersection with the ring road and also to the increasing customer
population to the east of the site.
The heavy use of the rear Cottonwood Road entrance by traffic traversing between the fiont and
rear of the store creates motorist confusion and conflicts between entering and exiting
movements. Specifically, that entrance was not designed to carry substantial traffic flows and
the throat depth available for storing exiting motorists is minimaL This issue has qparently
raised concern by the Village, and a "No Turns" sign has been installed at that location.
Aside from conflicts at the rear of the store, these back-to-fiont flows (and vice versa) are
constrained along the south side of the Wal-Mart store where relatively narrow lane widths are
provided. In addition, sight distance is restricted by the comer of the lawn and garden center at
the intersection of that side road with the parking lot, and the west leg of that intersection is
confi,wed at a skew.
E. Truck Access
The existing Wal-Mart store is served by loading docks at the southeast comer of the building.
Signage within this area denotes the Kriege Farm Road driveway as the truck entrance and the
Cottonwood Road drive as the truck exit. Although trucks do seem to follow that circulation
plan, truck operations are constrained due to the lack of a clear turnaround area. Specifically,
trucks were frequently observed maneuvering around vehicles parked near the Tire & Lube
Express as well as backing off of the site onto adjacent parking lots and roadways in order to
access the loading docks.
It was noted that the presence of parking within the center of the lot was not depicted on the
current site plan (or former plans) since that area was apparently designated as a truck
turnaround area. The addition of that parking (presumably to serve the Tire & Lube Express
demands) is contributing to the constrained truck operations.
Anticipated Changes in Site-Generated Traffic Associated with the Supercenter
It is our understanding that the existing 129,175 s.f. Wal-Mart store would be expanded to a 210,569
s.f. Supercenter. In order to accommodate the expansion, approximately 12,768 s.f. of shops and
restaurants immediately adjacent to the store would be removed. In addition, the existing
Cottonwood Mall, which contains a small movie theatre and some office space but is generally
underutilized, would be removed. That two-story facility contains approximately 53,638 s.f., though
much of that space is currently vacant. Finally, an existing shop space near the north of end of the
center (formerly Big Lots) would be reduced fiom 25,000 s.f. to 9,900 s.f. and a small 100 s.f. shop
would be added to the north end of the building.
In total, approximately 8 1,406 s.f. of space would be removed from the Plaza and 81,394 would be
added to Wal-Mart for a slight net decrease in total site square footage. However, many of the stores
that would be eliminated are "specialty retail" facilities (Payless Shoes, Radio Shack, CAT0
clothing store, etc.) that are relatively low traffic generators and, more importantly, the Cottonwood
Mall currently generates only minor peak period traffic activity despite its large square footage.
Conversely, the Wal-Mart addition, which will include groceries, would be expected to generate a
meaningful increase in traffic, though many of those additional trips would be "captured" from the
existing clientele.
In an effort to predict how much additional traffic would be generated by the supercenter, we
researched available reports published by the Institute of Transportation Engineers (ITE) as well as
data provided by Wal-Mart &om independent studies of other facilities. These resources produced
wide-ranging results that underscore the fact that Wal-Mart's trip generation can be heavily
influenced by population, building size and market area (presence of competing uses). However, it
Mr. Theo Stone
March 8,2007
Page 5
may be surmised that due to the "capturing" of existing patrons, the net increase in traffic is not
proportionate to the added floor area. In fact, there is some evidence to suggest that the net trip
generation rate (trips per 1,000 s.f. of floor area) for a Wal-Mart Supercenter is lower than for a
typical Wal-Mart store, though a more conservative approach was used in this analysis.
Based on a composite of the various resources, it was estimated that Wal-Mart Supercenters generate
traffic at a rate of 5.12 trips/l,OOO s.f. during the p.m. peak hour of a weekday and 6.19 trips/1,000
s.f. during the midday peak of a Saturday. These rates were used to forecast the trip generation for
the proposed store, from which traffic for the existing store was deducted using standard ITE rates
(5.06 trips/1,000 s.f. and 7.58 trips/1,000 s.f. for the p.m. and Saturday peak hours, respectively).
For the purposes of these calculations, it was also necessary to estimate the traffic activity that is
currently associated with the uses that would be removed as part of the proposed project. Fbr the
adjacent shops and shop space at the north end of the site, the ITE rates for Specialty Retail uses
were applied over their full square footage. However, in order to account for the hgh vacancy rate
and low activity of Cottonwood Mall, only 25% of its square footage was considered to be currently
"active."
The resulting calculations are summarized in Table 1. As can be seen, the proposed expansion
would be expected to generate a net increase of 315 trips during the p.m. peak hour and 215 trips
during the Saturday peak hour. On a daily basis, it is estimated that the supercenter would generate
an additional 4,670 trips.
It should be noted that these volumes represent total trips (both inbound and outbound). After
allowing for directional splits, the proposed expansion would add a maximum of 160 total vehicles
per hour (vph) either inbound or outbound during the p.m. peak hour. After distributing these trips
between the several primary access drives serving the site, it is likely than the net increase to any
individual movement at those locations would be relatively minor.
Anticipated Deficiencies and the Need for Improvements to Accommodate the Supercenter
Given the recent completion of the improvements to Route 159 and Cottonwood Road, it is
anticipated that sufficient capacity is available to accommodate the proposed expansion without the
need for M e r improvements on these external roadways (aside fi-om a right turn lane on
Cottonwood Road that is already proposed as part of the site plan). However, it is important to note
that the resulting increase in traffic activity would exacerbate the existing internal circulation issues
described above.
Therefore, we have provided several potential modifications to consider in conjunction with the
proposed expansion, as depicted in Exhibit 2 It should be noted that many of these suggestions
could be implemented independently of one another. The deficiencies and recommended corrective
measures are described as follows:
e Access tolfi-om West Ring Road
In order to correct the existing constraints along the west ring road, it is recommended that the
access between that road and the parking lot be modified. Specifically, the northernmost drive is too
close to Junction Drive and needs to be closed. A potential means of accommodating that closure
and facilitating improved access for Wal-Mart and the remainder of Cottonwood Plaza would be to
remove the existing canoe diverter island and facilitate a four-way internal intersection. In addition
to reducing conflicts along the ring road, that configuration would also provide more direct access
&om Route 159 into the parking lot, while accommodating the parking lot circulation changes
suggested below.
In order to address the sight distance constraints along the ring road, it is recommended that the
existing vegetation along the east side of the road be removed. Those bushes currently represent a
significant sight obstruction, and it would be important to address that safety concern as part of the
proposed project.
0 Parking Conflicts
In order to address the existing circulatory constraints within the parking lot, it is recommended that
the lot be reconfigured to provide a delineated, contiguous internal circulation drive along its
western extents. As depicted in Exhibit 2, this drive could be accommodated through the use of
islands (preferably raised) at the end of each parking aisle. Some of the resulting parking losses
could be recaptured along the western edge of the lot.
In addition, it would be appropriate to provide a continuous raised island along at least one of the
parking aisles in fi-ont of the store. This island would prevent motorists from cutting across the
parking lot (an existing factor in the high number of parking lot collisions at this site) and provide
clear direction regarding the appropriate circulatory patterns within the lot. A raised island in this
Mr. Theo Stone
March 8,2007
Page 7
location could also potentially be used as a pedestrian walkway for customers to use between the lot
and the fiont of the store.
Clearly, the recommended modifications would have an impact on the parking yield within this lot.
If all of the potential improvements were implemented as suggested, approximately 40 less parking
spaces would be provided versus the base site plan. However, it was also noted that 9.5-foot wide
spaces are provided in front of Wal-Mart, while only 9-foot wide spaces are required (and are
provided within the rest of the lot to the north). The use of 9-foot parking spaces should allow the
majority of the potential parking losses to be recaptured.
0 Access Constraints to
In order to address current constraints and improve access to the Wal-Mart parking lot from the ring
road, it is recommended that the ring road be widened to provide a second northbound lane fiom
lane. The provision of this auxiliary lane would allow motorists to bypass any blockages in the
inside (existing) northbound lane and reduce the potential for spillbacks into the signalized
intersection with
Traffic Flows Between Front and Rear of Store
As previously discussed, the heavy use of the rear site entrances and the resulting flows between the
fiont and back of the store (along the south side of the building) create conflicts currently. These
concerns are likely to worsen with the expansion of the store and ongoing residential growth to the
east of the site. Furthermore, it is our understanding that a lawn and garden pick-up drive is
proposed along the south side of the store as part of the expansion project, and that modification
would further reduce the available width of the drive (which is already constrained).
In order to address these issues, it is recommended that consideration be given to restricting the
south-side access dnve to service only eastbound traffic flows. This modification would
significantly reduce traffic flows utilizing the rear access drives, while still allowing access between
the fiont and rear of the store. In particular, an eastbound configuration of the drive would allow
customers parked within the fiont lot to use the lawn and garden pick-up drive without leaving the
site.
Truck Access
The proposed changes for access between the front and rear of the store would also reduce traffic
activity within the existing loading zone at the southeast comer of the site. However, the presence of
parking within the turnaround area would still constrain truck maneuvers. In order to address that
issue, consideration should be given to removing or reducing the allowed parking within that area,
though alternative locations for parking (should it need to be replaced) are not apparent.
Mr. Theo Stone
March 8,2007
Page 8
Based on the proposed site plan, it appears that a second loading dock area would be constructed to
service the grocery portion of the Supercenter. Unfortunately, the turnaround area depicted for that
truck dock is also within an existing prking field behind
duplicating the constraints associated with the existing loading area, it is recommended that a clear
truck turnaround be provided (free of regular parking) to the extent possible.
In closing, it should be reiterated that it is our belief that this site is capable of accommodating the
proposed store expansion &om a traffic engineering perspective. The proposed internal circulation
modifications would ease existing constraints and facilitate safer and more convenient access to and
within the site.
We trust that you will find this assessment useful in evaluating traffic conditions associated with the
proposed
questions or comments concerning this material or if you require any additional information.
Sincerely,
<-
Dustin B. Riechmann, P.E., PTOE
Project Engineer
