PCI/IRI/PCR: Formulas to Combine to Rate an Urban Street Network

@2016 ESRI User Conference

Diane Binnie/ Ryan FrancoforteSteve Loo/Raj Shah

COH Street Pavement Rating System:Past

• PCR (Pavement Condition Rating) Basis

• Two rounds of data collected for Major & Local Roads

• PCR = 100 – Rutting – Cracking – IRI

IRI(ride quality )

PCI(pavement distress)

PCI & IRI Distinctions

PCI (Pavement Condition Index)

• Pavement Surface Distresses

• Leading Indicator (generally)

• Engineer’s use for Treatment Determination

IRI (International Roughness Index)

• Ride Quality

• Lagging Indicator (generally)

• Citizen/Driver’s notice

• Important dimension to assess road conditions.

COH Street Pavement Rating System:Present/Future

• Now collecting PCI separated out

• PCI is adopted by APWA (American Public Works Association)

• Based on ASTM D6433 published standard (American Society for Testing and Materials)

• PCI is a “Numerical Indicator” that rates surface condition of the pavement

Conceptually with various agencies

PCI =100-(Sum of all deducts)

19 for Concrete / 20 for Asphalt

Then some deducts were eliminated

OCI =100-(80% PCI max +20% IRI max)

PCR = 100-(50% PCI max+50% IRI max) for Major

PCR = 100-(80% PCI max+20% IRI max) for Local

COH used several years

PCR = 100 – (Sum of Rutting+ Cracking+ IRI)

PCR = 100-(15%Rutting max +25%Cracking max+30%max IRI)

Conceptually, PCI/IRI influence on PCR was: PCR = 100 –(57% PCI max + 43% IRI max)

Conceptual PCR formula based on PCI & IRI influence of Street Network

characteristics/needs(Physical/Demand/Functional Condition assessment)

Why the change to PCI…

1. PCI provides present condition of pavement surface

2. PCI helps determine what treatments and where (right treatment on the right pavement at the right time)

3. PCI allows for feedback on maintenance treatments (validation of current practices)

4. PCI is used to evaluate materials & designs

Additional PCI information:

Repeatable methodology

Pavement distresses are objectively scored based on type, severity and extent

Every street is rated with the same standard

PCI score range is 0 (worst possible condition) to 100 (best possible condition)

PCI can be used as a tool/aid to rank streets relative to each other

Automated Distress Inspection• Quantifiable Results

• Low subjectivity

• High repeatability

Alligator Cracking

Patching & Joint Reflection Cracking

Potholes

Edge Cracking

COH Condition Assessments1. Physical (PCI)

• Reflects the physical state of the asset, which can be used in determining asset

performance

• Asset performance can be used to provided required level of service to customers

• Critical information for determining remaining useful life and timing for possible

intervention steps

COH Condition Assessments2. Demand (ADT Data)

• Examines asset’s capacity over the long-term

• Assets must be utilized effectively in order to provide the maximum return on

funds invested and to deliver the required levels of service.

COH Condition Assessments3. Functional (IRI/Ride Index)

• Deal with the suitability or ‘fitness for purpose’ of the asset

• Suitability needs to recognize service needs for current and future purposes.

• By assessing the suitability of an asset, opportunities for varying the level of

service, and hence the cost of service, can be considered.

Past & PresentSimilarities:

1) Use Class 1 ASTM E950 Profiler to record IRI –“Ride Quality”

2) Automated Pavement Data Collection (rut, crack, ride quality data)

3) Pavement Data collected on 100% of lanes driven

4) Tool/aid for relative ranking of street segment’s pavement condition

5) Use best available/most recent data

6) PCR & PCI scale range is 0 to 100

Past & PresentDifferences:

• Utilizing more lasers presently

• Collecting more passes on wider major streets presently (inside and outside lanes)

• Collecting more passes on local streets presently (both directional lanes as opposed to one lane)

Allows for more educated

planning/decision making

Potential Reasons for score differences (Past & Present)

1) PCR and PCI are different: comparison cannot be made because they rate different aspects of pavement in different ways PCR & PCI scores are affected by pavement decay, repair, rehabilitation & reconstruction

2) Continual Decay of pavement generally would move scores downward (trucks, buses, cars, moisture changing conditions, drought, oxidation, etc.)

3) Continual Repair & Rehabilitation work generally move scores upward

4) Reconstruction work move scores upward

Past SSAV(COH owned)

Present SSAV(DTS owned)

PMIS – StreetSaver with PCI data examples:(rating colors/categories/thresholds are draft)

Collected Data Integrated with ESRI

In summary, PWE acquired an upgraded Street Pavement Rating System:

1) Based on ASTM D6433 standard adopted by APWA

2) Up to 5 SSAV vans available from vendor

3) Data Collected on more lanes

4) More RUT Lasers & more CRACK Lasers

5) Enhanced Crack Identification

6) Results piped into a Pavement Management Information System (PMIS) to manage data

Questions?