TRANSPORTATION ADVISORY BOARD AGENDA ITEM
ACTION REQUESTED:
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Approve a Recommendation to Establish a 25 MPH Speed Limit for the Atwater Subdivision
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DEPARTMENT: Transportation, Engineering and Development
SUBMITTED BY: Michael Prousa, TED Project Manager
BACKGROUND:
Atwater is a newer subdivision bounded by Diehl Road (north), Fairway Drive (east), North Aurora Road (south), and Shore Road (west). The streets in Atwater have been operating under the default 30 mph limit established by the Illinois Vehicle Code.
DISCUSSION:
The Transportation, Engineering and Development Business Group (TED) investigated the need for neighborhood speed limits for Atwater. Staff has received several recent requests for speed limit signage in the Atwater subdivision.
The study warrants used to establish speed limits are located in Section B of the Illinois Department of Transportation (IDOT) "Policy on Establishing and Posting Speed Limits" and the Illinois Vehicle Code.
This IDOT Policy uses the 85th percentile speed (the speed at which 85 percent of the vehicles are driving at or below) and other adjustment factors for potential conflicts that includes the number of driveways, pedestrians, crashes, and on-street parking to determine the recommended posted speed limit.
Traffic data was collected at 3 different representative locations across the Atwater subdivision. Maps of the proposed streets and their locations are attached. The 3 studies were done on Alderleaf Lane, Balsam Cove Road, and Country Club Boulevard from July 8 - July 15, 2020.
The 85th percentile speed and the upper 10 mph pace for Alderleaf Lane was 33.5 mph and 30 mph. The prevailing speed is the average of the 85th percentile and the upper 10 mph pace, which equates to 31.75 mph. The 85th percentile speed and the upper 10 mph pace for Balsam Cove Road was 33.5 mph and 30.5 mph. The prevailing speed was 32 mph. The 85th percentile speed and the upper 10 mph pace for Country Club Boulevard ...
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