Overview of the ROMDAS System

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• Overview of the ROMDAS System

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Presentation Contents

• Background to ROMDAS
• Principles of Road Measurement
• Asset Management Surveys
• Roughness
• Condition Rating
• GPS
• Transverse Profiles
• Video Logging
• Congestion

• Setting up the Software
• Installing ROMDAS in the Vehicle
• Calibration
• Surveys
• Data Processing
• Problem Solving

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Development of ROMDAS

• 1989 Simple Roughness Logging
• 1991 PC Version
• 1996 Transverse Profile Logger, Video System
• 1997 Congestion, Crossfall
• 1998 GPS, Skid Resistance, BI, DMI
• 1999 Traffic Surveys, Manual Counter, Gyroscope
• 2000 Direct Digitising, Road Management System
• 2003 ROMDAS Windows software released

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ROMDAS Components
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ROMDAS Hardware Interface
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ROMDAS Equipment
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ROMDAS Software

• Over 14,000 lines of code
• Written in C and Clipper
• Runs on any IBM Compatible PC
• Regular updates and new releases

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Underlying Principles

• Low cost
• Must be portable
• Works with any vehicle
• Use readily available technology
• Robust
• Simple to operate

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Argentina
Philippines
Thailand
UK
New Zealand
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Malaysia
Fiji
India
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Tonga
Kenya
India
New Zealand
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Supplementary Programs

• Road Management System - Integrates data from all
  instruments in a single framework
• Video Play - Play digitised videos
• Profile Viewer - View transverse profiles

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Over 120 Systems Used In 40 Countries

• Argentina
• Australia
• Bangladesh
• Barbados
• Bhutan
• Bosnia
• Brazil
• Chile
• China
• Colombia
• Croatia
• Ecuador
• El Salvador
• Ethiopia
• Fiji
• France
• India

• Indonesia
• Ireland
• Kenya
• Lao PDR
• Malawi
• Malaysia
• New Zealand
• New Caledonia
• Nicaragua
• Pakistan
• Philippines
• Samoa
• South Africa
• South Korea
• Tanzania
• Thailand
• Tonga

• Trinidad and Tobago
• Ukraine
• United Kingdom
• Uruguay
• Vietnam
• Zambia

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Types of Applications
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Principles of Road Measurement
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Terminology

• Chainage location along a road from start
• LRP location reference point used as a survey
  reference point
• Keyboard Rating recording events with the PC
  keyboard.
• Continuous event - an event which applies over a
  section of the road
• Point event - an event on or adjacent to the road
  which applies to a point
• Transverse Profile - the pavement profile across
  a lane

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Location Referencing

• THE most important element of any project
• Road projects use linear system although spatial
  has a role
• Surveys always start and end at same point but
  NEVER get exactly same measured distance
• Creates problems reconciling data

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Location Reference Points

• Regular points established along road at 1 - 5 km
  intervals
• Km stones, culverts, bridges, any permanent
  feature
• Distance between them is not important only that
  they will not move
• All data expressed as an offset from LRP

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Location Referencing Example
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Example of LRP Resets
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Example of ODO Error on Distance
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Distance Measurement Accuracy

• Function of number of pulses generated from DMI
• Affected by
• Tyre pressure
• Tyre temperature
• Speed
• ROMDAS high resolution DMI 5 mm resolution
  standard 0.2 - 0.5 m resolution

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Keyboard Rating

• During survey the operator uses the keyboard or
  mouse to record the location of events on or
  adjacent to the road
• Any key can be assigned to a point or continuous
  event
• Anything that can be observed can be recorded

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Example of Ratings
ALWAYS include a no defect in any rating
system or will have problems in analyses
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ROMDAS Rating Keyboards
20 Key Rating Keyboard
58 Key Rating Keyboard
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Surveying Adjacent Sections
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Asset Management Study Surveys
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Survey Requirements

• Typically collect data on
• Roughness
• Rut Depth
• Surface Condition (eg Cracking, Potholes,
  Ravelling)
• Inventory
• Rise and Fall/Curvature
• Road Width/Shoulder Width
• Traffic Volume
• GPS?
• Video?

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Types of Data

• Inventory Data
• physical elements of road network that do not
  change markedly over time
• Condition Data
• elements of the road network that change over
  time
• Traffic Data

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Deciding What to Collect

• What decisions do we need to make?
• What data are required to make these decisions?
• Can we afford to collect the data?
• If it needs updating, can we afford to keep data
  current over time?

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Criteria for Selecting Data Items

• Relevance
• Appropriateness
• Reliability
• Affordability

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Relevance

• Every data item must have a direct influence on
  the project output
• Data relevance depends on the items ultimate use
  
• Data items which are considered to be desirable,
  interesting or possibly useful should be omitted

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Appropriateness

• Technology and resources used in acquiring,
  processing and managing the data should be
  appropriate to the capacity for maintaining the
  equipment, conducting the surveys and processing
  the data
• Data collected to appropriate level of detail

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Appropriateness ...

• If looking over time, frequency of data
  collection based on rate of change of item
  out-of-date data are often irrelevant
• Trade-offs need to be made between precise data
  collected infrequently on the one hand and less
  precise data collected more frequently

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Reliability

• Levels of accuracy and reliability vary
  considerably between different applications
• Data must be consistent over time and between
  locations
• The aim should be to have high levels of
  repeatability and reproducibility

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Precision vs Speed
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Affordability

• Size and quality of all data and their
  acquisition must be affordable in terms of cost
  and resources
• Scope of data collection weighed against
  resources required

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Guiding Principle

• Collect only the data you need!
• Collect it only when you need to!
• The level of detail should be appropriate for the
  decisions being made network level data for
  network level analyses project level for project
  level

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Information Quality Levels (IQL)

• Introduced by World Bank to help determine data
  requirements and design systems
• Recognises that different levels of data are
  needed for different levels of management
  activities
• Ensures that only enough data are collected to
  enable appropriate decisions to be made

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IQL
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IQL Pyramid
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Information
Good information does not guarantee sound
management but bad information makes sound
management difficult
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Roughness Surveys
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Roughness

• The bumpiness of the road
• Important indicator of pavement condition and
  also influences vehicle operating costs
• Usually expressed in terms of IRI International
  Roughness Index

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IRI Simulation
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IRI Scale
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Roughness Measurements

• Class 1
• Manual profiler
• Class 2
• Non-contact Profilometer
• Class 3
• Response-type Roughness Meter (Bump Integrator)

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ROMDAS Bump Integrator
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ROMDAS BI Installed in Vehicle
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Types of BI Installations
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BI Mounting
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Condition Rating Surveys
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Visual Inspections
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Measurements Using ROMDAS

• Keycode rating surveys used to record distresses
• Operator presses a key and the chainage of the
  distress
• Point and Continuous Events
• If you can see it from the vehicle you can
  collect the data with ROMDAS

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Surface Distresses

• Cracking
• None
• Low
• Medium
• High
• Disintegration
• Ravelling
• Potholing
• Bleeding
• Delamination

• Edge Defects
• Edge Break
• Edge Drop

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Cracking Can Be Identified By

• Shape
• Block
• Crocodile
• Longitudinal
• Location
• Edge
• Wheelpath

• Cause
• Fatigue
• Thermal
• Reflection
• Ageing
• Manner of Development
• Top-Down
• Bottom-Up

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Block Cracking
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Crocodile Cracking
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Disintegration

• Distress affecting surfacing course
• Ravelling
• Loss of stone and binder
• Potholes
• Bleeding (Flushing)
• Surface aggregate immersed in binder
• Delamination
• Complete loss of surfacing

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Edge Defects

• Edge break
• On narrow pavements due to traffic moving off
  edge
• Shear forces cause edge to break
• Edge drop
• High lip on edge of pavement
• Increases shear forces and contributes to edge
  break

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Edge Defects
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GPS Surveys
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GPS

• 24 satellites in 6 orbital planes 20,200 km above
  earth
• Orientation means that usually 5 satellites in
  view from any point on earth
• Satellites broadcast radio signal

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Method of Measurement

• GPS receiver measures time taken for signal to
  reach receiver
• Timings analysed to triangulate the position
• Minimum of four readings required to determine
  time, latitude, longitude and elevation

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Satellite Triangulation
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GPS Accuracy

• Depends on
• error in range measurements
• geometry or relative positions of the satellites
  and the user (Dilution of Precision)

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Example of Dilution of Precision
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Typical GPS Errors
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Improved Accuracy

• Differential GPS uses secondary source to correct
  for errors in field survey
• Base station
• Satellite system (e.g. OmniStar)

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ROMDAS and GPS

• ROMDAS works with any GPS receiver
• Queries receiver on 1 s basis and stores GPS and
  chainage data
• Accuracy entirely dependent upon receiver

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Transverse Profile Surveys
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Transverse Profile Logger

• Transverse profile measurements used to calculate
  the rut depth and distortion
• ROMDAS uses ultrasonics for measurements

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ROMDAS Transverse Profile Logger (TPL)
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TPL With Wings Extended
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Installing the TPL
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ROMDAS Transverse Profile Measurements
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Composite Profile
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Calculating Rut Depth
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ROMDAS Rut DepthCalculation Method
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Distortion
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Field Validation of Measurements
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Transverse Profile Testing
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Observed vs Predicted Rutting
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TRL Beam Sampled vs True Rutting
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ROMDAS Rut Depth Tests
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ROMDAS Elevation Tests
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Temperature Effects on TPL Measurements
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ROMDAS Profile Viewer
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Calculating Crossfall
?c ?r ?h
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Crossfall Scenarios

• Both positive
• Road to TPL negative TPL to horizontal positive
• Road to TPL positive TPL to horizontal negative

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Crossfall Data

• Use a roll gyroscope to measure angle of TPL to
  horizontal
• Angle of TPL to pavement
• Use a linear regression on transverse profile
  data to get angle of TPL to pavement
• Use elevation height differences between
  wheelpaths or edges of pavement

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TPL to Road Regression
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Calibrated Roll Option

• Uses a calibration of the roll gyro to the
  crossfall
• Results less accurate than using TPL data

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Video Logging Surveys
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Videologging Surveys

• Provides permanent record of road environment
• Best to supplement data collected from keycode
  rating and instruments
• Can be digitised to be stored and played back on
  computer

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ROMDAS Video System
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V 2 Video System Enclosure
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V 2 Video System Components
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Example of Digitised Video(2 Frames/sec)
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Example of VideoPlay Software
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Moving Traffic Surveys
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Moving Traffic Surveys

• Record the number of vehicles travelling in
  opposite direction
• ADT Vehicles/time
• Adjust by time of day/day of week to make convert
  to AADT

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Moving Survey vs 7-day Count (India)
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Congestion Surveys
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Surveys Used To

• Identify capacity problem locations
• Determine level of service
• Establish impact of road improvements
• Input to feasibility studies
• Transportation planning studies

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ROMDAS

• Designed to calibrate HDM-4 congestion model
• Considers effects of traffic interactions on
  vehicle operating costs

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HDM Speed-Flow Model
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Acceleration Noise
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Traffic Effects
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Skid Resistance Surveys
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Findlay Irvine GripTester
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Calibration
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Calibration Procedure

• Distance Measurement Instrument
• Roughness Meter
• Transverse Profile Logger

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DMI Calibration

• Measure 100 m using static tape
• Run ROMDAS over 5 times
• Mean used for calibration factor

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Roughness Calibration

• Identify test sections covering full range of
  roughnesses to be encountered in survey
• Used reference instrument to establish roughness
• Calculate IRI from reference instrument
• Run ROMDAS over each section 5 times at each
  survey speed
• Establish relationship between ROMDAS raw
  measurements and IRI

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IRI Calibration
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TPL Calibration

• Static calibration to establish TPL distance
  correction factors
• Verification test to confirm that the
  measurements are - 1.0 mm or better with 95
  confidence
• Sensor relative height calibration

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TPL Distance Calibration
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Example of Verification Tests
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ROMDAS Road Management System
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Purpose

• Single application to review all data collected
  in a survey
• Can drive down the road and view the data
• Contains utilities for processing data
• Calibrate videos
• Creating LRP files
• Creating survey routes
• Integrating .DBF files into Access database
• Joining short survey sections into one file

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Example of Display
Roughness
Video
Keycode
Digital Photos
Transverse Profile
Voice Recordings
Raw Data
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Summary
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Surveys

• ROMDAS can be used for
• Roughness
• Keycode Rating
• Transverse Profiles/Rut Depths
• Video Logging
• GPS
• Traffic Counts
• Congestion
• Skid Resistance

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System

• Portable and easy to install
• Collects data rapidly and efficiently
• Proven in a range of countries