WEIGH‐IN‐MOTION ON THE ILLINOIS TOLLWAY
October 16, 2019
Master Sgt. Steven LeGrand, Illinois State Police District 15Michel Lavigne, Illinois Tollway GEC
Welcome and introductions…
Overview of WIM technology…
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Reduces overweight vehicle traffic
Increases pavement life
Data gathered assists with future pavement designs and enforcement
Uses sensor inputs to calculate• Classification• Weights • Speed • Vehicle length
Presented by MSgt. Steven LeGrand and Michel Lavigne on October 16, 2019
PURPOSE OF WEIGH ‐ IN ‐MOTION
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With axle spacing and weight the WIM is able to determine vehicle’s classification.
Definition
• WIM system is the process of measuring the dynamic tire forces of a moving vehicle and estimating the corresponding tire loads of the static vehicle
• Provides vehicle count, classification and speed in addition to weight
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EXISTING AND PROPOSED LOCATIONS
Presented by MSgt. Steven LeGrand and Michel Lavigne on October 16, 2019 3
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Advantages• Installed by saw cuts only • Plate can be removed and replaced
Disadvantages• Cavity below bending plate must be cleaned annually to prevent drain clogging
• Components require annual maintenance and calibration
Presented by MSgt. Steven LeGrand and Michel Lavigne on October 16, 2019
TECHNOLOGYBENDING PLATE
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Reducing road surface degradation around the plate.
Meets ATSM 1318 Type III for accuracy (GVW±6 percent).
Bad installation can create premature pavement degradation.
Salt corrosion of metallic parts.
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TECHNOLOGYQUARTZ SENSORS
Presented by MSgt. Steven LeGrand and Michel Lavigne on October 16, 2019 5
Advantages• Embedded in pre‐cast concrete slab • Can be replaced with minimum saw cut
Disadvantages• Five‐year maximum longevity
Graphic Source: FHWA
Meets ATSM 1318 Type III for accuracy (GVW±6 percent).
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TECHNOLOGYPRECAST
Presented by MSgt. Steven LeGrand and Michel Lavigne on October 16, 2019 6
Precast installation on the Northbound Tri‐State Tollway (I‐294/I‐80) just north of the Chicago Southland Lincoln Oasis
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TECHNOLOGYS ITE SELECTION CRITERIA
Presented by MSgt. Steven LeGrand and Michel Lavigne on October 16, 2019 7
• High‐volume truck zone preferable
• Weigh‐in‐motion systems must be located upstream of a safe location to pull over trucks
• Straight, smooth and level existing pavement
• Close proximity to power and communication infrastructure
Jane Addams Memorial Tollway (I‐90) at Beverly Road WIM
Example: crash investigations sites and mainline toll plazas.
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FACTORS AFFECTING TECHNOLOGY SELECTION
• Reliability of ITS components• Locations that allow successful installation• Array of sensors to be installed• Sensitivity of sensors
• Temperature, vehicle dynamics, traffic volume, speed
• Resilience of sensor installation• Calibration frequency and accuracy of readings
• Life span of sensors and other components
• Life‐cycle costs – components, operations and maintenance, vendor support
Presented by MSgt. Steven LeGrand and Michel Lavigne on October 16, 2019 8
Functional Performance Requirements for WIM Systems
*Includes single or dual tires Source: FHWA
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TECHNOLOGY EVALUATION
Standardizing deployment
Minimizing operations and maintenance costs
Minimizing risk of failure
Presented by MSgt. Steven LeGrand and Michel Lavigne on October 16, 2019 9
Lane Unidirectional Bending Plate – Staggered Configuration
Source: FHWA
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SELF ‐CALIBRATING
Actual weights are entered into the program by the user, who calibrates weigh‐in‐motion system
Reduces amount of maintenance/calibration required
• Weigh‐in‐motion is officially recalibrated annually, along with quarterly maintenance
Presented by MSgt. Steven LeGrand and Michel Lavigne on October 16, 2019 10
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SELF ‐CALIBRATINGRESULTS
Presented by MSgt. Steven LeGrand and Michel Lavigne on October 16, 2019 11
Steer Drive Trailer GVW Steer Drive Trailer GVW
1 3.2% 6.5% 2.8% 4.4% ‐2.4% ‐1.0% ‐0.6% ‐1.1%
2 4.8% 4.2% 3.1% 3.9% ‐1.6% ‐2.6% ‐1.2% ‐1.9%
3 3.2% 3.9% 5.9% 4.6% ‐3.2% ‐1.3% ‐1.9% ‐1.9%
4 4.8% 5.2% 1.9% 3.7% ‐4.0% ‐1.3% ‐2.8% ‐2.4%
5 4.8% 3.6% 4.3% 4.1% ‐3.2% ‐0.3% ‐2.5% ‐1.7%
6 4.8% 5.2% 5.3% 5.2% ‐3.2% ‐2.3% ‐2.5% ‐2.5%
7 4.8% 4.2% 1.9% 3.3% ‐2.4% 1.3% ‐2.8% ‐1.1%
8 3.2% 4.9% 1.9% 3.3% ‐6.5% ‐6.2% 1.5% ‐2.9%
9 3.2% 3.9% 2.5% 3.2% ‐4.0% ‐1.3% 0.9% ‐0.8%
10 2.4% 3.3% 4.3% 3.6% 1.6% ‐2.0% ‐2.8% ‐1.7%
Average 4.0% 4.5% 3.4% 3.9% ‐2.9% ‐1.7% ‐1.5% ‐1.8%
Run
Piezo Quartz Error
Before Calibration
Piezo Quartz Error
After Calibration
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TESTING NEW TECHNOLOGIES
Tire Anomaly Classification System• Tire anomalies and flat tires• Potential safety issues with vehicleimbalance and improper load distribution
• Pilot project planned on Veterans Memorial Tollway (I‐355) weigh‐in‐motion rebuild
• Easily integrated with existing weigh‐in‐motion
Presented by MSgt. Steven LeGrand and Michel Lavigne on October 16, 2019 12
• Decreases directional control
• Increases the risk of catastrophic failure
• Negatively impacts tire life and fuel economy
Mismatched and missing tires result in vehicle imbalance and improper load distribution
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TESTING NEW TECHNOLOGIES
Illinois Department of Transportation installed six TACS statewide since 2017, operated by the Illinois State Police
Presented by MSgt. Steven LeGrand and Michel Lavigne on October 16, 2019 13
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TESTING NEW TECHNOLOGIESBR IDGE WEIGH ‐ IN ‐MOTION
Presented by MSgt. Steven LeGrand and Michel Lavigne on October 16, 2019 14
Testing west of the Tri‐State Tollway(I‐294/I‐80) WIM
• Not used for enforcement• Proximity to WIM allows for system checks
Veterans Memorial Tollway (I‐355) WIM scheduled for repair
• >10‐year expected life• Upgrade will use the same technology as the
Tri‐State Tollway (I‐294/I‐80) install
Reagan Memorial Tollway (I‐88) WIM being studied in conjunction with Aurora Toll Plaza
I‐355 scheduled to be upgraded with tire anomaly sensor (spring 2020)
Thornton Quarry Bridge on the Tri‐State Tollway (I‐294/I‐80)
• Places sensors on steel beams, reads deflection on them and returns a projected weight of vehicle
• Non-invasive, since it is not in the pavement
Not accurate enough today
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WEIGH ‐ IN ‐MOTION ENFORCEMENT
Master Sgt. Steven LeGrand, Illinois State Police
Presented by MSgt. Steven LeGrand and Michel Lavigne on October 16, 2019 15
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Infrastructure protection• Increases pavement life
Improves road safety by removing overloaded trucks
• Reduces amount of tire debris, which causes accidents and vehicle damage
• The Federal Motor Carrier Safety Administration has shown large truck and bus crashes are directly proportional to vehicle weight
Presented by MSgt. Steven LeGrand and Michel Lavigne on October 16, 2019 16
OVERWEIGHT ENFORCEMENT RESULTS
Overloaded trucks are at an increased risk of accidents due to the steering and handling characteristics being altered by excess weight, reduced braking capabilities.
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IDEAL CONDITIONS FOR ENFORCEMENT
Presented by MSgt. Steven LeGrand and Michel Lavigne on October 16, 2019 17
Permanent scales provide ideal locations for weighing trucks off the main roadway
The locations contain parking areas for commercial vehicle enforcement.
Due to the large area needed to accommodate the scales, locations are limited.
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ENFORCEMENT PAD
Presented by MSgt. Steven LeGrand and Michel Lavigne on October 16, 2019 18
Parking on the roadway or on the shoulder is dangerous
Off‐roadway parking is ideal for enforcement
Original Veterans Memorial Tollway (I‐355) site required ISP troopers to park next to the weigh‐in‐motion cabinet
The WIM cabinet provided a series of lights that indicated a possible overweight truck.
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Located at Hillside (M‐2) maintenance site
First permanent scale in history of the Illinois Tollway/Illinois State Police District 15
Presented by MSgt. Steven LeGrand and Michel Lavigne on October 16, 2019
PERMANENT SCALE
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ISP troopers look for the following signs of an overweight truck in order to conduct enforcement: • Bulging tires• Trucks accelerating slowly or having trouble stopping• Improperly loaded/leaning trailer, carrying large/heavy machinery, etc.
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WEIGH ‐ IN ‐MOTION DISPLAY
Presented by MSgt. Steven LeGrand and Michel Lavigne on October 16, 2019 20
Weighs vehicles at highway speeds
Collects data on vehicles for the Tollway Engineering Department and for statistical purposes
The main function is to assist ISP with enforcing weight requirements for commercial vehicles in Illinois.
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WEIGH ‐ IN ‐MOTION AT TRI ‐STATE TOLLWAY ( I‐294/I‐80) CHICAGO SOUTHLAND L INCOLN OASIS
Presented by MSgt. Steven LeGrand and Michel Lavigne on October 16, 2019 21
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Provides weights and photos to Illinois State Police laptops in real‐time
Troopers can park anywhere safely downstream, monitor weigh‐in‐motion via laptop and conduct enforcement
Current technology ensures an error rate of +/‐ 10 percentPresented by MSgt. Steven LeGrand and Michel Lavigne on October 16, 2019
TRUCK TRACKING SOFTWARE
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However, we are currently around 5-7 percent error rate and with frequent calibrations expect that to go down to 5 percent.
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ENFORCEMENT
Presented by MSgt. Steven LeGrand and Michel Lavigne on October 16, 2019 23
Weigh‐in‐motion data can only be used for detection – not enforcement
Must use scales certified by the Illinois Department of Agriculture
Permanent scale or wheel‐load weighing can be used
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VIRTUAL WEIGH STAT ION SOFTWAREVEHICLE RECORD DETAILS AND PHOTO DISPLAY
Presented by MSgt. Steven LeGrand and Michel Lavigne on October 16, 2019 24
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I N S ERT WHEE L LOAD WE IGH ING I N ACT ION V IDEO
Presented by MSgt. Steven LeGrand and Michel Lavigne on October 16, 2019 25
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WEIGH ‐ IN AREAS
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Provided to protect troopers• Manual side of Spring Creek Toll Plaza• Crash investigation sites (with guardrail protection)
• Hillside (M2) maintenance site permanent scale
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JANE ADDAMS MEMORIAL TOLLWAY ( I ‐90) CRASH INVESTIGATION SITE
Presented by MSgt. Steven LeGrand and Michel Lavigne on October 16, 2019 27
Allows for safe weighing and inspection
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QUESTIONS?
Master Sgt. Steven [email protected]
Michel [email protected]
Presented by MSgt. Steven LeGrand and Michel Lavigne on October 16, 2019 28
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THANK YOU
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