PCI

Function Description: Follows ASTM D6433-07 and uses the "Distress" and "Sample Unit" layers to summarize the quantity or affected extent of each distress type and severity within every sample unit, calculate PCI, and associate the results with a trajectory or Road Center Line. The section results are stored as vector points in the "PCI Section" layer.

Input Conditions

  • The project must contain a verified "Distress" layer. Distress type, severity, and geometry directly participate in calculation

  • The project must contain a "Sample Unit" layer covering the pavement to be evaluated. It defines the range and area of each calculation unit

  • A project trajectory or Road Center Line is required to associate sample unit PCI with road sections in the "PCI Section" layer

Operation Steps

1.After distress detection, distress verification, and sample unit checking are complete, click PCI to open the settings dialog

2.Select the data source and road line vector and set the parameters

3.Click OK to calculate PCI, and check the generated "PCI Section" layer

Parameter Settings

ParameterDescription
Data SourceSelect the trajectory (trajectory data in the project) or a Road Center Line vector layer. When using a Road Center Line, you can select the entire layer or pick an individual vector line from the layer
Severity Level ThresholdDefines severity thresholds for distress types. Defaults follow ASTM D6433-07

The thresholds recalculate severity only for the seven point cloud-detectable distress types. Other distress retains the severity already stored in the "Distress" layer, so complete verification before calculation.

PCI Calculation Process

Based on ASTM D6433-07:

1.Divide Sample Units: Divide the target area by the specified area. The default is 255 m²

2.Count Distresses: Count quantity by type and severity in three categories:

  • Count category: Potholes

  • Length category: Bumps, Edge Cracks, Reflection Cracks, Lane/Shoulder Drop-off, Longitudinal Cracks, Transverse Cracks

  • Area category: Alligator Cracks, Bleeding, Block Cracks, Corrugations, Depressions, Patches, Polished Aggregate, Railroad Crossings, Rutting, Shoving, Slippage Cracks, Swells, Weathering/Raveling 3.Calculate Percentage Density: Quantity ÷ Sample Unit Area × 100

4.Query Deduct Value Curve: Obtain the individual Deduct Value (DV)

5.Determine CDV: If only zero or one DV is greater than 2.0, CDV is the sum of DVs. Otherwise:

  • 5.1 Sort DVs in descending order

  • 5.2 Calculate allowable deduction items m = 1 + (9/98)×(100-HDV), where HDV is the maximum DV

  • 5.3 Calculate TDV for the first m items, count items > 2.0 as q, and look up CDV from the table

  • 5.4 Set the last item > 2.0 in the m-th item to 0 and recalculate CDV

  • 5.5 Iterate until only one item > 2.0 remains, and take the maximum CDV 6.Calculate PCI: PCI = 100 - CDV

7.Generate PCI Sections: Associate the result with a trajectory or Road Center Line and store it in the "PCI Section" layer

Output Results

  • PCI Section Layer: Records PCI for road sections and can be used to view pavement condition along the road and export the report

  • PCI Interpretation: A higher PCI indicates better pavement condition. As distress quantity, affected extent, or severity increases, deduct value increases and PCI decreases

After modifying the "Distress" or "Sample Unit" layer, recalculate PCI so the "PCI Section" layer does not retain outdated statistics.

Common Prerequisites

  • Without a "Distress" layer, the effect of distress on PCI cannot be calculated

  • Without a "Sample Unit" layer, the PCI calculation units and their areas cannot be determined

  • Without a trajectory or Road Center Line, results cannot be associated with road sections in the "PCI Section" layer

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