Pavement condition index

The pavement condition index (PCI) is a numerical index between 0 and 100, which is used to indicate the general condition of a pavement section. The PCI is widely used in transportation civil engineering and asset management, and many municipalities use it to measure the performance of their road infrastructure and their levels of service. It is a statistical measure and requires manual survey of the pavement. This index was originally developed by the United States Army Corps of Engineers, but later it was standardized by the ASTM. The surveying processes and calculation methods have been documented and standardized by ASTM for both roads and airport pavements: 
Calculation.
The method is based on a visual survey of the number and types of distresses in a pavement. First, the type and extent of existing distresses, their severity level is collected. Next, distress density is calculated for each type of distress. The density values are translated into deduct value (DV) and corrected deduct value (CDV) using a set of curves proposed by the ASTM. The ASTM does not include the formulae of these curves, but they are recalculated by researchers. Finally, the value of the PCI is calculated in an iterative process. The result of the analysis is a numerical value between 0 and 100, with 100 representing the best possible condition and 0 representing the worst possible condition.
Pavement distress types for asphalt pavements include: 
For relatively small pavement systems, the entire system may be surveyed. For large pavement systems, the process may involve surveying a random or representative sample of the entire system with the following steps:
This condition index can give a good indication of the pavement condition of a network. However, trained personnel are required to complete the complicated survey procedure.
Categorization.
The ASTM divides the PCI into seven classes as follows, but in practice a PCI lower than 40 is almost impassable.
Relationship with roughness.
PCI is correlated with the performance indicators measuring roughness such as international roughness index (IRI) and present serviceability rating (PSR). Generally, a road with a high PCI has a low IRI, and a road with a high IRI has a low PCI. However, this is not always the case. For example, two roads with the same PCI can have significantly different IRI values as a result of having different types of distresses or grades. 