Weigh-In-Motion (WIM) Data Collection & Reporting

Office of Highway Policy Information2012 Highway Information Seminar - Session: 6BThursday, October 25, 2012 8:00 am – 9:30 amBy: David L. Jones Sr. ,Transportation Specialist

• Provide Background and Update • Describe Truck Weight Program • State Reporting Requirements (TMG) Update• WIM System Deployment & Sensor Technology• Identify Data Collection Issues • TWS Status & National Loading Trends• Open Discussions dialogue

OBJECTIVE

• 1831 Thaddeus Fairbanks• 1918 BPRs First Road Test• 1934 Hayden-Cartwright Act• 1939 Type A

Loadometer

181 Years of Vehicle Weighing

• 1942 Strain Gage Load Cell

• 1950 O.K. Norman

181 Years of Vehicle Weighing

• 1985 Traffic Monitoring Guide

• 1955 AASHO Road Test Approved• 1971 TWS Manual

181 Years of Vehicle Weighing

• 2012 Traffic Monitoring Guide Update

• Ensure Quality Input Data• Provide Latest Procedural and Program Guidelines • Transferable Techniques and Procedures• ITS Data• Bike and Pedestrian

TMG Update Project Goals

• Chapter 1 – Traffic Monitoring Theory, Technology, and Concepts

• Chapter 2 – Traffic Monitoring Program – Business Planning and Design

• Chapter 3 – Traffic Monitoring Methodologies• Chapter 4 – Traffic Monitoring for Non-

Motorized Traffic

Table Of Contents

• Chapter 5 – Transportation Management and Operations

• Chapter 6 – HPMS Requirements for Traffic Data• Chapter 7 – Traffic Monitoring Data Formats• Appendices:

Table Of Contents

• Speed• Non-motorized data• Data Formats • Reporting Requirements• Expanded Examples, Appendixes and References

What’s New

• Updated ~2+ days NHI TMG Training Course• Public Website: http://fhwatmgupdate.camsys.com/

Other Associated Work

Project Information // Project Schedule // Panel Members // Panel // Public Review and Comment

Weigh-In-Motion?

Process of Measuring Dynamic Tire ForcesUsing in Pavement Sensors

To Estimate a Static Vehicle Weight

Why Weigh?

• Pavement Design / Maintenance

• Pavement Design / Maintenance• Bridge Design / Loading

• Pavement Design / Maintenance• Bridge Design / Loading

• Pavement Design / Maintenance• Bridge Design / Loading• Enforcement

• Pavement Design / Maintenance• Bridge Design / Loading• Enforcement• Research

• Pavement Design / Maintenance• Bridge Design / Loading• Enforcement• Research• Freight Movement

Why Weigh in Motion?• Traffic Stream• Use of the Highway System

Truck Weight Program Components• Users Needs

– End in Mind– 2002 Pavement Design Guide

• Resources– Federal-aid and construction funds

• Locations– Available funds

• Truck Weight Groups– Criteria for groups

A. Define truck weight roadway groups

Maximum Weight in a Given Weight Group (x 1,000 lbs)

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50

Fra

cti

on

of

Ax

les

in

Eac

h W

eig

ht

Gro

up

Heavily Loaded

Moderately Loaded

Lightly Loaded

Tandem Axle Load Distributions

A. Define truck weight roadway groupsRural Urban

Interstate and arterial major through-truck routes

Interstate and arterial major through-truck routes

Interstate and arterial major truck routes Interstate and arterial major truck routes

Other roads (e.g., regional agricultural roads) with little through traffic

Other roads (e.g., regional agricultural roads) with little through traffic

Interstate and other freeways serving primarily local truck traffic

Interstate and other freeways serving primarily local truck traffic

Special cases (e.g., recreational, ports)

A. Define truck weight roadway groups

B. 6 sites / groupRural Urban

Interstate and arterial major through-truck routes

Interstate and arterial major through-truck routes

Interstate and arterial major truck routes Interstate and arterial major truck routes

Other roads (e.g., regional agricultural roads) with little through traffic

Other roads (e.g., regional agricultural roads) with little through traffic

Interstate and other freeways serving primarily local truck traffic

Interstate and other freeways serving primarily local truck traffic

Special cases (e.g., recreational, ports)

A. Define truck weight roadway groups

B. 6 sites / group

C. One continuous WIM within group Capture day-of-week and seasonal changes within each group

A. Define truck weight roadway groups

B. 6 sites / group

C. One continuous WIM within group Capture day-of-week and seasonal changes within each group

D. Calibrate, Calibrate, Calibrate

Criteria for Groups

• Can be easily applied in any state• Logical means for disguising between

heavy and light loaded roadways

WIM Sensor Technology

Bending Plates” – Strain gauge/load cellsLoad Cell” – Hydraulic load cellsPiezo” -electric cables/film/quartzCapacitance” mats/pads/stripsBridge” Strain gauges on bridge beams

Minimum quarterly WIM submittal truck weight data from permanent weight-in-motion (WIM) sites within 26 days after the close of the quarter.

***Monthly WIM Submittal is Encouraged***

Reporting Requirements

Truck Weight Study Status

TMASProducts• System wide Vehicle weight by vehicle class• Axle Load Distribution• Equivalent Single Axle Load (ESAL)• Day-of-Week and Seasonal Patterns

W-Tables (TWS)• W1-Weigh Station Characteristics• W2-Comparison of Weighted vs. Counted• W3-Average Empty, Loaded, and Cargo Weights• W4-Equivalency Factors• W5-Gross Vehicle Weights• W6-Overweight Vehicle Report• W7-Distribution of Overweight VehiclesVTRIS Reports:

https://fhwaapps.fhwa.dot.gov/vtris-wp/

COMPARISON OF GROWTH IN VOLUME AND LOADINGS ON THE RURAL INTERSTATE SYSTEM

1970 72 74 76 78 80 82 84 86 88 90 92 94 96 98 00 02 04 06 080

100

200

300

400

500

600

700

RURAL AVERAGEDAILY LOAD

RURAL AVERAGEDAILY TRAFFIC

YEARSource: Truck Weight Study

Rural Interstate Travel by Vehicle Type

1 Equivalent axle loads provide a means of measuring vehicle wear on pavements by relating them to an 80 kilonewton (18,000 pound) single axle load.

2 All 2-axle, 4-tire trucks. Includes pickup trucks, panel trucks, vans and other vehicles (such as campers, motor homes, etc.)3 All vehicles on a single frame have either 2 axles and 6 tires or 3 or more axles (including camping and recreational vehicles and motor homes.)

80

246

16

92

Average Daily Traffic Equivalent Single Axle Loads0

20

40

60

80

100

Per

cent

Automobiles, Buses and Light Trucks

Heavy Single Unit Trucks

All Combination Trucks

Distribution of Average Daily Traffic Volumes and EquivalentAxle Loads on the Rural Interstate System as a Percent of Total

Urban Interstate Travel by Vehicle Type

1 Equivalent axle loads provide a means of measuring vehicle wear on pavements by relating them to an 80 kilonewton (18,000 pound) single axle load.

2 All 2-axle, 4-tire trucks. Includes pickup trucks, panel trucks, vans and other vehicles (such as campers, motor homes, etc.)3 All vehicles on a single frame have either 2 axles and 6 tires or 3 or more axles (including camping and recreational vehicles and motor homes.)

89

44

14

7

82

Average Daily Traffic Equivalent Single Axle Loads0

20

40

60

80

100

Per

cent

Automobiles, Buses and Light Trucks

Heavy Single Unit Trucks

3- & 4-Axle Combination Trucks

Distribution of Average Daily Traffic Volumes and Equivalent

Axle Loads on the Rural Interstate System as a Percent of Total

Source: VTRIS Truck Weight Study

Distribution of Vehicle Travel by Laneby Vehicle Type

57.1

42.9

21.3

78.7

11.3

88.7

Lane 2 Lane 10

10

20

30

40

50

60

70

80

90

100

Per

cen

t

Greater than 10M tons per year5 to 10 M tons per yearLess than 5 M tons per year

0

20,000

40,000

60,000

80,000

100,000

120,000

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Av

era

ge

Da

iy G

VW

Month

Statewide Average Gross Vehicle Weight (GVW)by Functional Classification

Single_Unit

Single_TT

Multi_TT

Monthly Average GVW Variations

State of Maryland South Bound I83 June 25 2004

0

10,000

20,000

30,000

40,000

50,000

60,000

70,000

80,000

90,000

00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23

Hour of Day

Ave

rag

e G

ross

Veh

icle

Wei

gh

t(P

ou

nd

s)

Average GVW Class 9 Truck

Hourly Average GVW Variations

Data Quality ActData Quality

Quality Assurance Statement

The Federal Highway Administration provides high-quality information to serve Government, industry, and the public in a manner that promotes public understanding. Standards and policies are used to ensure and maximize the quality, objectivity, utility, and integrity of its information. FHWA periodically reviews quality issues and adjusts its programs and processes to ensure continuous quality improvement.

Requests for Correction

On October 1, 2002, the Department of Transportation (DOT) issued agency guidelines to ensure the quality of disseminated information. If you are affected by information that the Department has disseminated on or after October 1, 2002 (i.e., if you are harmed because the information does not meet the standards of the guidelines or a correction of the information would benefit you), you may request that the Department correct that information. We regard information originally disseminated before October 1, 2002, as being subject to this correction process only if it remains readily available to the public (e.g., it is posted on a DOT website) and it continues to play a significant, active role in Department programs or in private sector decisions. Information on how to submit a request can be found at http://dms.dot.gov/dataquality.cfm

Data Quality Elements

• Data collection• Data Processing• Process improvement• Implementation plan• Data quality program.

FUTURE

WIM’s Future Role

• National estimates of heavy vehicle highway travel on a monthly basis

• National estimates of axle loadings and highway ton-miles of freight moved each month, and

• Highway specific estimates of truck volumes and loadings

Travel Monitoring Analysis System

46

Traffic Volume TrendsGISFreight ManagementSafety

“THE EASY BUTTON”

Travel Monitoring Analysis System

Session 6B Summary• Truck Weight User Needs?• Truck Weight Program Components?• Submittal Requirements?• Data Quality?• Truck Weight Data Reports?

Questions

• What questions do you still have about the Traffic Monitoring Program?

• Expectations met?

THANK YOU !

David L. Jones Sr.djones@dot.gov