Values Deduced to Apply the Pavement Condition Index Methodology to Ecuador

1. Introduction

One of the most complete pavement evaluation methods used worldwide is the PCI (Pavement Condition Index), a method developed by Shahin & Kohn (1979) originates in the technical report M - 268 published by the United States Army Corps of Engineers (1968). This methodology allows us to assess the condition of road pavement, taking into account the deterioration that the road may have at the time of evaluation. The purpose of using the methodology is to ensure proper maintenance based on the level of deterioration.

The type of maintenance chosen for a road must ensure that Fthe road meets its intended lifespan. Therefore, it is crucial to recognize that preventive maintenance may not reveal severe conditions of the road, potentially leading to increased costs to provide optimal road service, periodic conservation and maintenance actions, on the other hand, extend the road’s lifespan and keep it in acceptable operating conditions (Obregón-Biosca et al., 2015).

Nowadays, due to the functional and structural characteristics provided in roadways, asphalt pavements are the most widely used in the construction of road networks in the majority of countries. The quality and design of the asphalt mixtures used in these pavements largely depend on their performance during the operational or service phase (Zhao et al., 2025).

The PCI method utilizes values derived from charts by ASTM (American Society for Testing and Materials) Standard D6433 - 03, titled “Standard Practice for Roads and Parking Lots Pavement Condition Index Surveys.” The values prescribed in the standard are associated with factors contributing to pavement deterioration, which manifests from the moment a road is constructed (Choez Pibaque, 2022). Various methodologies exist for pavement evaluation, including Visual Inspection of Road Infrastructure (VIZIR), PCI, and Pavement Surface Evaluation and Rating (PASER).

The choice of pavement evaluation method will depend on each country and its stakeholders, considering the specific needs of each region (Vásquez Varela, 2002). For instance, in Ecuador, the PCI methodology is employed due to its ease of calculation and the fact that it does not necessitate specific tools or equipment for its application. However, this methodology bases its results on studies conducted in a country with a different context than the local one, rendering these results less suitable for accurate evaluation.

Several models and methodologies are integral components of management systems, originating from the detailed analysis of the current state of roadways. The objective is to bring about a change in the interurban-urban landscape through the prediction of deterioration (Guaita Luján, 2016).

In Nevada and Louisiana, United States, an analysis of the road conditions has been conducted using a methodology tailored to the specific characteristics of the region. This has allowed the execution of practical and accurate studies to evaluate the roadways, employing computerized applications ASTM International (2003). However, it has been identified that these analyses in Nevada and Louisiana do not lead to changes or variations in the deduction curves inherent to the method (Loria et al., 2016). Similarly, in Iran and India, there has been an exploration of the possibility of using programs that automate calculations, such as Soft Computing and Information Solutions. These programs assess pavement conditions using historical data to predict the value of the Pavement Condition Index (PCI). Although these software applications contribute to research, they do not exhibit similar characteristics (Shahnazari et al., 2012).

In South America, research on pavement conditions has been conducted in Chile, Venezuela, Peru, and Colombia. These studies are primarily based on the PCI method, and through manuals and software applications, they have facilitated the calculation of PCI. It is important to cite several investigations that have contributed to our research, such as the work of the Saba et al., (2006), Rodriguez Velasquez (2009), Nuñez Caiminagua & Salazar Avilés (2015), Hurtado Arias (2016) and Ibragimov et al., (2024).

These researchers have conducted roadway studies using the PCI method without alterations, employing it solely to generate road maintenance plans. This research aims to establish values for determining the local pavement condition index based on the conditions and characteristics of Ecuadorian roadways, using the local Pavement Serviceability Index (PSI).

2. Methodology

The deduction curves used by the PCI methodology are based on the Service Index Pavements, these two values being significantly related, so the curves will be the result of the factors that affect the Service Index Pavements (Vásquez Varela, 2002). The deduction curves determined in this research will be evaluated by experts as part of the Validation process of the research results.

The evaluation will also consider the Pavement Serviceability Index (PSI), related to climatic, geographical, and environmental factors associated with each roadway. The resulting PSI values will be analyzed using statistical methods, supported by graphs and tables. The simplicity of obtaining PSI makes it an easily accessible value, as it does not require a specific prior study to determine.

To get the Pavement Serviceability Index, it suffices to have a well-maintained vehicle. The individual responsible for obtaining this value will remain inside the vehicle, focusing on perceiving and determining the PSI value. Additionally, the person inside the vehicle should assess the roadway based on the movement experienced while traveling. This approach serves as an effective means for users to determine the extent of damage, such as potholes or irregularities, allowing for the evaluation of whether the roadway is in good condition, facilitating reliable service, or if it is in poor condition.

Upon analyzing all the data, new curves of deduced PCI values tailored to the Ecuadorian context will be generated. Through this methodology, maintenance plans will be formulated to align with our local reality, recognizing that the continuous assessment and upkeep of roads contribute to the proper formation of the road network, a necessity for both the social and economic development of Ecuador.

An adequate road maintenance process seeks greater accuracy as much as possible since it would generate a lower government cost for roads currently the data obtained by the Ministry of Transportation and Public Works presents a value of 200 million dollars annually specifically for road maintenance using the PCI methodology.

According to the characteristics of our areas and with values based on our road reality, the methodology will show us more real and accurate results. In Ecuador, for every road maintenance plan, studies are needed through methods such as Vizir (French auscultation methodology) and PCI. In Ecuador, through the Ministry of Transportation and Public Works, the evaluation of the condition of existing pavements in the territory has been carried out using the PCI Method, however, only the values of the method have been considered. It is necessary to investigate roads in the countries, as it is an important point for their emergence.

3. Results

3.2 Deduction curves based on the analysis of PCI vs PSI of road sections

To get the percentage that the PCI in Ecuador is below the PCI in the United States, 15 samples of road sections in the province of Chimborazo were analyzed, to appreciate the variability that the Pavement Condition Index will have, this is obtained through the abacuses proposed by the original PCI methodology regarding the local Service Index.

The roads in the United States undergo continuous maintenance, considering high-quality standards to be optimal, therefore, the penalty imposed by these abacuses is quite high, generating a low PCI compared to our local reality. Active 1: The deterioration factors that directly influence the generation of new deterioration curves will penalize the deduced values, thus obtaining a PCI for Ecuador that should be higher compared to the original methodology.

To carry out the analysis of the Deduction curves, we started by looking for the best road sections, those that provide a “Very Good” PSI Ecuador index according to our assessment, and from 15 samples taken, the Pavement Service Index was determined, which is compared with the optimal PSI according to the ASSHTO, resulting in variability of 20% as shown in Table 1 and Figure 1 because in our country the roads still provide ideal service conditions and according to the penalty of foreign regulations they are not found in such a way.

Table 1. Sampling values and percentage of variation.

Road section	PSI optimal	PSI ecuador optimal
1	5.00	4.1
2	5.00	3.8
3	5.00	4.2
4	5.00	4.2
5	5.00	4.0
6	5.00	3.9
7	5.00	4.0
8	5.00	4.2
9	5.00	3.8
10	5.00	3.8
11	5.00	3.9
12	5.00	3.8
13	5.00	4.1
14	5.00	4.1
15	5.00	4.1
Average	5.00	4.0
Road State	Good	Good
%	100%	80%
Variation Of Percentage	20%

Figure 1. PSI (EEUU-Optimal) Vs. PSI (Ecuador).

A. Road pavement condition index focused on ecuador, based on evaluation of pavement serviceability index

The 20% variability in the Ecuadorian Pavement Serviceability Index (PSI) was considered and applied to the Pavement Condition Index (PCI) method, commonly used for pavement evaluation. This choice was made because the values derived from the PCI method are the ones that penalize pavement conditions. This variability can be differentiated in Table 2 and Table 3.

Table 2. PSI ASSHTOO and PCI.

PSI (AASHTO)		Condition	PCI
5	4	Good	100%	80%
4	3	Satisfactory	80%	60%
3	2	Fair	60%	40%
2	1	Poor	40%	20%
1	0	Very Poor	20%	0%

Table 3. PSI Ecuador and PCI Ecuador.

PSI (AASHTO)		Condition	PCI
5	4	Good	100%	80%
4	3	Satisfactory	100%	80%
3	2	Fair	80%	60%
2	1	Poor	60%	40%
1	0	Very Poor	40%	20%

With the analysis performed previously and adapting the variations to the local reality, we obtain the deduction curves for each damage ( Figures 2–6) and the general curve to determine the corrected deduction value ( Figure 7). In this context, 19 deduction curves are proposed for each type of failure in the flexible pavement such as: Alligator Cracking, Bleeding, Block Cracking, Bumps and Sags, Corrugation, Depression, Edge Cracking, Joint Reflection Cracking, Lane/Shoulder Drop Off, Longitudinal & Transversal Cracking, Patching & Utility Patching, Polished Aggregates, Potholes, Railroad Crossing, Rutting, Shoving, Slippage Cracking, Swell, Weathering/Raveling. It should be noted that each type of failure has a high (H), medium (M) and low (L) severity level. The curves described above have been adapted from the failure types developed by the United States Army Corps of Engineers (USACE) and are documented in the American standard ASTM D6433.

Figure 2. Alligator cracking, bleeding, block cracking, bumps and sags.

Figure 3. Corrugation, depression, edge cracking, join reflection cracking.

Figure 4. Lane/Shoulder Drop/off, longitudinal and transverse cracking, patching, polishing aggregate.

Figure 5. Potholes, railroad crossing, rutting, slippage cracking.

Figure 6. Parabolic cracks, swelling, raveling.

Figure 7. Corrected deduced value.

4. Conclusions and future work

The variation of the Pavement Condition Index (PCI) by 20% from the AASHTO, based on the service required by our road reality, allowed the determination of each point where the curves of original deduced values from the PCI methodology are defined. Polynomial equations governing each logarithmic curve could be generated, considering an 80% penalty relative to the 100% recommended by the standard for each of the 19 damages. Damage number 19, related to weathering, could be considered as aggregate polished aggregates, penalizing with values lower than the deduced ones. However, it exhibits similar deterioration characteristics, leading to the definition of the same deduction curves.

Future research should aim to establish a database using the results obtained in this study and compare them with data obtained previously with no variation in the methodology. This comparison would help identify whether an appropriate budget for maintenance plans in Ecuador can be achieved based on these results.

Ethical approval

This research did not involve human participants, human data, or biological samples. Therefore, ethical approval from an institutional review board (IRB) or ethics committee was not required. The study focused exclusively on engineering analysis and the evaluation of pavement condition data obtained from secondary, non-human sources.