CITY COUNCIL AGENDA ITEM
ACTION REQUESTED:
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Waive the first reading and pass the ordinance to establish a 25 mph speed limit for several subdivisions and streets across Naperville (requires six positive votes)
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DEPARTMENT: Transportation, Engineering and Development
SUBMITTED BY: Michael Prousa, TED Project Manager
BOARD/COMMISSION REVIEW:
On October 1, 2020, the Transportation Advisory Board (TAB) recommended approval to establish a 25 mph speed limit at several subdivisions and streets across Naperville. (Approved 9-0)
BACKGROUND:
Several small subdivisions in Naperville have not had the neighborhood 25 mph speed limit established on their streets. Most of these streets, constructed in the mid 2010’s or later, have been operating under the default 30 mph limit established by the Illinois Vehicle Code.
Staff from the Transportation, Engineering and Development Business Group (TED) has received several recent requests for speed limit signage and conducted a study to investigate the need for speed limits.
DISCUSSION:
The Study
The 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 such as the number of driveways, pedestrians, crashes, and on-street parking, to determine the recommended posted speed limit.
In total, 65 streets without established speed limits were included in the study. Most of the streets were cul-de-sacs so traffic data was collected at six different representative locations across the city. The study locations were chosen based on characteristics including length, number of driveways, and intersection streets.
The six studies were done from September 11 - September 18, 2020 at Centennial Court, Paisley Lane, Shandrew Drive, Formby Road, Castle Lawn Court and Heatherfield Circle. Maps of the streets with the proposed speed limits, as well as the representative locations, are attached.
Centennial Court
The 85th percentile, and the upper 10 mph pace, was 17 mph and 18.5 mph. The prevailing speed is the average of the 85th percentile and the upper 10 mph pace, which equates to 18 mph.
Paisley Lane
The 85th percentile, and the upper 10 mph pace, was 18.5 mph and 18.5 mph. The prevailing speed was 18.5 mph.
Shandrew Drive
The 85th percentile, and the upper 10 mph pace, was 29.5 mph and 29.5 mph. The prevailing speed was 29.5 mph.
Formby Road
The 85th percentile, and the upper 10 mph pace, was 22 mph and 22.5 mph. The prevailing speed was 22.5 mph.
Castle Lawn Court
The 85th percentile, and the upper 10 mph pace, was 26.5 mph and 27.5 mph. The prevailing speed was 27 mph.
Heatherfield Circle
The 85th percentile, and the upper 10 mph pace, was 26 mph and 27 mph. The prevailing speed was 26.5 mph.
Section B of the IDOT manual allows for adjustments when altering a speed limit due to road factors identified above. The following are the allowable conflict reductions for each street:
1. 10% for driveways
a. All six locations have greater than 61 driveway and street intersection conflicts per mile.
2. 5% for pedestrian
a. Centennial Court is the only location that is on a school walk route and therefore an adjustment is needed.
3. 0% for crashes
a. The crash rate is determined by comparing the amount of crashes on a given road to the citywide average per year. All six locations have a crash rate lower than 1.5 which equates to no adjustment.
4. 5% for parking
a. All six locations have sufficient width for on-street parking.
Considering all the allowable reductions, the adjusted prevailing speed is calculated to be 14 mph for Centennial Court, 16 mph for Paisley Lane, 25 mph for Shandrew Drive, 19 mph for Formby Drive, 23 mph for Castle Lawn Court, 23 mph for Heatherfield Circle. The adjusted prevailing speed is set to the nearest 5 mph increment, which establishes a speed limit of 25 mph as the lowest possible speed limit in accordance with the IDOT manual and the Illinois Vehicle Code. The speed study worksheets illustrating the allowable reductions and location maps are attached.
Recommendations
The characteristics of the six streets are representative of conditions throughout the city on similar streets. The study warrants establishing a uniform 25 mph speed limit on the following streets:
|
No. |
Streets |
Area of Restriction |
|
1 |
Amelia Court |
Orleans Av to Terminus |
|
2 |
Arrowwood Road |
Nannyberry St to 248th Av |
|
3 |
Ashwood Park Court |
103rd St to Terminus |
|
4 |
Bethany Court |
Terrance Dr to Terminus |
|
5 |
Birchgrove Drive |
111th to Pond Willow Dr/Pond Willow Ct |
|
6 |
Bourbon Court |
Bourbon Ln/Elyse Ln to Terminus |
|
7 |
Brabazon Court |
Formby Ct/Formby Rd to Terminus |
|
8 |
Brushwood Court |
Heatherfield Cr to Terminus |
|
9 |
Caliente Circle |
248th Av (North) to 248th Av (South) |
|
10 |
Castle Lawn Court |
75th St to Terminus |
|
11 |
Catherine Avenue |
Charles Av to Cotswold Dr |
|
12 |
Catherine Court |
Cotswold Dr/Catherine Av to Terminus |
|
13 |
Centennial Court |
Jackson Av to Terminus |
|
14 |
Colletta Circle |
Plank Rd (West) to Plank Rd (East) |
|
15 |
Compass Court |
Hobson Rd to Terminus |
|
16 |
Cotswold Drive |
Chicago Av to Catherine Av/Catherine Ct |
|
17 |
Declan Court |
Naperville Wheaton Rd to Terminus |
|
18 |
Elijah Drive |
Shiva Ln/Shiva Ct to Mya Ct |
|
19 |
Elyse Lane |
Ursuline Av to Bourbon Ln/Bourbon Ct |
|
20 |
Empress Drive |
Trumpet Av to Lobo Ln (North) |
|
21 |
Enclave Court |
Book Rd to Terminus |
|
22 |
Enterprise Court |
North Aurora Rd to Terminus |
|
23 |
Everwood Road |
Wehrli Rd to Stonebriar Ct |
|
24 |
Fisher Drive |
Diehl Rd to Country Club Bl |
|
25 |
Formby Court |
Brabazon Ct/Formby Rd to Terminus |
|
26 |
Formby Road |
Formby Ct/Brabazon Ct to Perth Dr |
|
27 |
Frontenac Court |
North Aurora Rd to Terminus |
|
28 |
Golf Ridge Circle |
Shore Rd (North) to Shore Rd (South) |
|
29 |
Heatherfield Circle |
Naper Bl (North) to Naper Bl (South) |
|
30 |
Kingsbridge Circle |
Catherine Av (West) to Catherine Av (East) |
|
31 |
Kingsley Court |
Ring Rd to Terminus |
|
32 |
Leona Mae Court |
Plank Rd to Terminus |
|
33 |
Lobo Court |
Olcan Rd/Lobo Ln to Terminus |
|
34 |
Lobo Lane |
Olcan Rd/Lobo Ct to Empress Dr (South) |
|
35 |
Madison Drive |
Wolfs Crossing Rd to Monroe Ct/Monroe Av |
|
36 |
Monroe Avenue |
Wolfs Crossing Rd to Monroe Ct/Madison Dr |
|
37 |
Monroe Court |
Monroe Av/Madison Dr to Terminus |
|
38 |
Murdcock Court |
Hobson Rd to Terminus |
|
39 |
Mya Court |
Elijah Dr to Terminus |
|
40 |
Nanak Court |
Barkdoll Rd to Terminus |
|
41 |
Nannyberry Street |
103rd St to Terminus |
|
42 |
Olcan Road |
Wolfs Crossing Rd to Lobo Ct/Lobo Ln |
|
43 |
Paisley Court |
Paisley Ln/Rosedale Av to Terminus |
|
44 |
Paisley Lane |
Shandrew Dr to Rosedale Av |
|
45 |
Pine Cone Court |
Royce Rd to Terminus |
|
46 |
Pinnacle Court |
Ford Ln/Baker Ln to Terminus |
|
47 |
Pond Willow Court |
Birchgrove Dr to Terminus |
|
48 |
Pond Willow Road |
Cedar Dr to Birchgrove Dr |
|
49 |
Rosedale Avenue |
Shandrew Dr to Paisley Ct/Paisley Ln |
|
50 |
Ryder Court |
Perth Dr to Terminus |
|
51 |
Saddlers Court |
Hobson Rd to Terminus |
|
52 |
Schillinger Court |
Book Rd to Terminus |
|
53 |
Shadow Creek Court |
Torrey Pines Ct/Shadow Creek Ln to Terminus |
|
54 |
Shadow Creek Lane |
Hobson Rd to Torrey Pines Ct/Shadow Creek Ct |
|
55 |
Shamrock Court |
Hobson Rd to Terminus |
|
56 |
Shandrew Drive |
Ogden Av to Blakely Ln |
|
57 |
Sharon Court |
Leverenz Rd to Terminus |
|
58 |
Shiva Lane |
Wehrli Rd to Shiva Ct/Elijah Dr |
|
59 |
Stonebriar Court |
Everwood Rd to Terminus |
|
60 |
Sutton Circle |
Book Rd (North) to Book Rd (South) |
|
61 |
Timber Trail Court |
Naper Bl to Terminus |
|
62 |
Torrey Pines Court |
Shadow Creek Ct/Shadow Creek Ln to Terminus |
|
63 |
Tramore Court |
Plainfield/Naperville Rd to Terminus |
|
64 |
Tranquility Court |
Hobson Rd to Terminus |
|
65 |
Winner’s Cup Court |
Plainfield/Naperville Rd to Terminus |
FISCAL IMPACT:
Speed limit signs are placed at the entrances of a subdivision. From the above list, 24 locations will receive speed limit signage with for an estimated total cost of $1,400.00.