Submitted By
Bill McKenna, Village Engineer Jack Chalabian, Transportation Commission Chairperson
Reviewed By
LKS
Agenda Item Title
Title
A Motion to Concur with the Transportation Commission’s Recommendation to Deny the Petition to Upgrade from Two-Way, East-West Stop Signs to All-Way Stop Signs at the Intersection of Cuyler Avenue and Iowa Street
End
Overview
Overview
The Village of Oak Park received a petition to install all-way Stop signs at the intersection of Cuyler Avenue and Iowa Street. The Village conducted crash analysis and traffic studies for the intersection. The Transportation Commission voted unanimously to recommend denying the petition to upgrade from two-way, east-west Stop signs to all-way Stop signs at the intersection of Cuyler Avenue and Iowa Street.
Body
Staff Recommendation
Approve the Motion.
Fiscal Impact
There is no fiscal impact for the Transportation Commission’s recommendations.
Background
On October 6, 2017, the Village of Oak Park received a petition to upgrade to all-way STOP signs at the intersection of Cuyler Avenue and Iowa Street. Persons representing 25.5% of the street frontage on the petitioning blocks signed the petition.
A copy of the petition was sent to the petitioner requesting additional signatures be obtained on the petition to make the petition valid. On December 12, 2017 the petition was resubmitted with additional signatures. Persons representing 51.1% of the street frontage on the petitioning blocks signed the petition. The petition was certified as a valid petition. Reasons provided for the petition are: drivers on Cuyler accelerate through this intersection because of the lack of a STOP sign, number of pedestrians that use this intersection, elementary students use the intersection on way to Whittier School, students wait for the Brooks School bus at the intersection, proximity to Whittier School, Dole Library, and Oak Leyden. See Attachment A for a copy of the petition and the related letter of explanation.
See Attachment B for copies of the written public testimony received by the Village for this item. There are a total of three emails included in the written public testimony; all in support of the upgrade to all-way STOP signs at the intersection of Cuyler Avenue and Iowa Street.
A twenty-four hour traffic volume count and speed study was conducted on Tuesday, February 20, 2018 for the 500 and 600 blocks of North Cuyler Avenue and 240 and 300 blocks of Iowa Street. The results were analyzed and then summarized (see Attachment F). Staff also reviewed the crash history of the intersection and generated a collision diagram based on the results (see Attachment H).
The petition was reviewed by the Transportation Commission at its March 22, 2018 meeting. Staff gave a presentation on the issue including: background on the petition, history of traffic control devices at the intersection, analysis of the collected traffic data and collision diagram. No spoken public testimony for this item was provided at the Commission meeting. After hearing Staff’s presentation, the Transportation Commission deliberated on the item. The approved minutes for the March 22, 2018 Transportation Commission meeting are included as Attachment I.
At the March 22, 2018 meeting, the Transportation Commission voted unanimously in favor of recommending to deny the petition to upgrade the intersection of Cuyler Avenue and Iowa Street from two-way, east-west STOP controlled to all-way STOP controlled intersection. See Citizen Advisory Commission Action section of this write-up for a complete listing of the Transportation Commission’s recommendations on this item.
ANALYSIS
Geometry of the Intersection and Neighborhood Context (Attachments C, D & E)
See Attachment C for digital aerial photographs of the Cuyler Avenue and Iowa Street intersection and the neighboring area. Dole Library is less than a block north of the Iowa Street and Cuyler Avenue intersection. Whittier School is one block north and half-block east of the intersection. As a result, many people in the area that walk to either the library or the school would have occasion to travel through the Iowa Street and Cuyler Avenue intersection.
Attachment D shows the traffic control devices on Iowa Street between Ridgeland Avenue and Austin Boulevard as well as adjacent east-west streets, Chicago Avenue and Augusta Street. Attachment E is the Safe Walking Route to School map for Whittier School with a red box around the intersection of Cuyler Avenue and Iowa Street. The Whittier School walking route indicated at the Cuyler Avenue and Iowa Street intersection is to walk north or south through the intersection with the protection of the existing traffic control devices (east-west STOP signs).
Traffic Study - Volume and Speed (Attachments F & G)
Reviewing the 24-hour volumes, the average daily traffic on the 240 and 300 blocks of Iowa Street was 722 and 756 vehicles, respectively. The average daily traffic was 623 vehicles and 660 vehicles for the 500 and 600 blocks of North Cuyler Avenue, respectively. Volumes on all four blocks fall below the 800 to 1,200 vehicle range for typical average daily traffic volume on the Village’s residential streets. Please see Attachment F for a summary of the vehicle traffic study results.
Regarding vehicular speeds, it is an accepted traffic engineering practice to set the speed limit to the 5 mile per hour increment above or below the 85th percentile speed. Village Staff holds the opinion that the majority of drivers will drive at or near the posted speed limit. In addition, it is an accepted fact that the speed indicated on speedometers can vary up to 2 percent above or below the actual speed of the vehicle.
By definition, the 85th percentile speed is the speed at which 85 percent of the vehicles are traveling at or less than. Conversely, 15 percent of the vehicles will be traveling faster than the 85th percentile speed. It has already been stated that speed limits are typically set to the 5 mile per hour increment above or below the 85th percentile speed. This implies that it is expected that approximately 15 percent of vehicles will be traveling faster than the speed limit, if the speed limit is the 5 mile per hour increment below the 85th percentile speed.
Looking at the 85th percentile speeds for the 240 and 300 blocks of Iowa Street, the directional speeds for the two blocks ranged between 23 and 28 miles per hour (mph). The 24-hour survey showed that 30.1% of the eastbound vehicles and 29.7% of the westbound vehicles on the 240 block of Iowa Street were traveling faster than the posted 25 mph speed limit. For the 300 block of Iowa Street, the percentage of vehicles traveling faster than the posted 25 mph speed limit were 3.1% for eastbound traffic and 3.2% for westbound traffic.
Looking at the 85th percentile speeds for the 500 and 600 blocks of North Cuyler Avenue, the directional speeds for the two blocks ranged between 24 mph and 25 mph. The 24-hour survey showed that 14.0% of the northbound vehicles and 14.8% of the southbound vehicles on the 500 block of North Cuyler Avenue were traveling faster than the posted 25 mph speed limit. For the 600 block of North Cuyler Avenue, the percentage of vehicles traveling faster than the posted 25 mph speed limit were 15.7% for northbound traffic and 17.0% for southbound traffic.
Based on the collected data, it appears there may be a slight speeding issue on the 240 block of Iowa Street. Village Staff recommends deployment of portable speed radar signs for a period of time on the block as well as targeted enforcement of the 25 mph speed limit to reduce the number of vehicles that are exceeding the speed limit on this block.
The Manual on Uniform Traffic Control Devices lists that STOP signs should not be used for speed control. Studies have shown there is little or no effect on vehicle speeds on residential roads after the installation of STOP signs. Vehicle speeds are reduced within 150 feet of the intersection otherwise the effect of STOP signs on vehicle speeds is negligible.
Attachment G provides a summary of the number of pedestrians crossing any of the Cuyler Avenue and Iowa Street intersection’s four legs during the 7:00AM-9:00AM and 2:00PM-4:00PM time periods. These time periods capture when students may be walking to or from Whittier School. Also included in the summary is the number of vehicles passing through the intersection during these same time periods.
For the morning two hour period, 58 pedestrians crossed one of the legs of the intersection while 263 vehicles traveled through the intersection. Twenty-four percent (24%) of the morning pedestrians traveled across Cuyler Avenue. In the afternoon two hour period, 62 pedestrians crossed a leg of the intersection while 239 vehicles traveled through the intersection. During this time period, 39% of the pedestrians walked across Cuyler Avenue. The increased number of pedestrians crossing Cuyler Avenue in the afternoon may be a result of the lower number of vehicles traveling through the intersection.
Crash History - Collision Diagrams (Attachment H)
Thirty-six months of vehicle crash reports covering the period of March 2015 through February 2018 were reviewed for the Iowa Street and Cuyler Avenue intersection. Please see Attachment H for the collision diagram. In 1998, the intersection was studied as part of the Village-wide traffic study. At that time, the number of reported crashes at the intersection in the 36 month period totaled zero, while the average daily traffic was 1,457 vehicles.
The 1998 crash rate for the Iowa Street and Cuyler Avenue intersection was calculated to be 0.000 accidents per million entering vehicles (Acc/MEV). This crash rate is then compared to the critical crash rate for the particular section of the Village’s area-wide traffic study. For the north section of the area-wide traffic study (North Boulevard to Augusta Street and Harlem Avenue to Austin Boulevard), the critical crash rate is 0.860 Acc/MEV. If an actual accident rate exceeds the critical crash rate then it is highly probable that the accidents were caused by factors other than chance.
The number of reported crashes that occurred at the Iowa Street and Cuyler Avenue intersection for the thirty-six months ended February 28, 2018 totaled zero. The average daily traffic for the intersection as determined as part of this traffic study is 1,380 vehicles. From this data, the 2018 crash rate for the Iowa Street and Cuyler Avenue intersection is calculated to be 0.000 Acc/MEV. This crash rate is lower than the critical crash as determined in the area-wide traffic study of 1998 (0.686 Acc/MEV). In conclusion, there does not appear to be a problem with vehicle crashes at the Iowa Street and Cuyler Avenue intersection.
Alternatives
The alternative to this recommendation could be to delay action to gain additional information.
Previous Board Action
N/A.
Citizen Advisory Commission Action
The Transportation Commission recommended the following:
1. Deny the petition to upgrade to all-way STOP signs at the intersection of Cuyler Avenue and Iowa Street.
2. Deploy portable speed radar signs on the 240 block of Iowa Street
3. Do targeted enforcement of the 25 mph speed limit.
4. Replace the two-way plaques with CROSS TRAFFIC DOES NOT STOP plaques under the east-west STOP signs.
5. Collect additional data from the speed radar signs.
6. Reach out to the petitioners and residents to educate them about other options within the Traffic Calming Toolbox.
The motions passed seven to zero.
Anticipated Future Actions/Commitments
None at this time.
Intergovernmental Cooperation Opportunities
N/A.
Performance Management (MAP) Alignment
N/A.