# Equity in Transportation Asset Management: A Proposed Framework
## 2 Materials and Methods
### Objectives
\[E_{C,k}=\sum_{i=1}^{N}\sum_{j=1}^{J}\sum_{t=1}^{T}\bigl{(}gc_{tij}\bigr{)} \tag{4}\]  
where  
\(gc_{tij}=\) the average GHG emission due to a specific M&R treatment type \(i\) on section \(j\) at time \(t\). Different scenarios can be defined for construction activities, including doing nothing, applying preservation treatments, implementing rehabilitation treatments, performing reconstructions, or conducting maintenance. Preservations are proactive treatments that aim to protect the existing pavement and extend its service life, resulting in lower construction emissions compared to more extensive rehabilitation or reconstruction methods. Rehabilitation treatments involve partial pavement restoration, requiring moderate construction emissions but leading to reduced traffic disruptions compared to full reconstruction. Reconstruction treatments involving complete pavement replacement typically result in higher construction emissions due to the extensive nature of the work. Maintenance activities address minor pavement issues and prevent further deterioration, potentially causing lower construction emissions, but may lead to increased traffic disruptions if not appropriately planned. Emissions due to traffic disruption (\(E_{T,k}\)) are another critical factor to consider. Traffic disruption also refers to the inconveniences and disturbances caused to traffic flow and road users during construction activities. It can lead to significant traffic congestion, resulting in increased fuel consumption and adverse effects on air quality. Lane closures, road diversions, and reduced road capacity can create bottlenecks, causing vehicles to move too slowly. Consequently, cars consume more fuel than usual, leading to higher emissions of GHG and other pollutants. Reduced traffic flow efficiency due to congestion can further exacerbate air pollution, as vehicles spend more time on the road emitting pollutants. To address these issues, pavement management systems should carefully consider planning and scheduling activities to minimize the impact on traffic flow. The \(E_{T,k}\) is a function of the traffic volume and the duration required to apply the M&R treatment. It can be quantified using the Equation (5) [23; 32]. \[E_{T,k}=\sum_{i=1}^{N}\sum_{j=1}^{J}\sum_{t=1}^{T}\bigl{(}gd_{tij}\bigr{)}\cdot AADT _{jt} \tag{5}\]  
where  
\(AADT_{jt}=\) the expected annual average daily traffic on section \(j\) in year \(t\). \(gd_{tij}=\) the marginal increase in GHG emissions of treatment \(i\) due to traffic disruptions on section \(j\) at time \(t\) for each unit of \(AADT\). Based on previous studies, the unit costs for the scenarios and their estimated GHG emissions from construction and traffic disruptions are included in Table 1, which serves as a schematic table for this [19; 23; 39]. The third aspect of sustainability is the economical point of view, in which pavement condition plays a vital role. Pavement condition assessment relies on various indicators or indices that reflect its overall state or level of service. These include pavement structural condition indicators such as the pavement structural number and distress score, as well as pavement functional condition indicators like the International Roughness Index (IRI) and riding quality. There are also indicators that combine both structural and functional conditions, such as the Pavement Condition Index (PCI) and Pavement Condition Rating (PCR). While different state Departments of Transportation (DOTs) use various pavement condition indices based on their own policies and the data they collect in their pavement management systems, the PCI provides a standard way to assess pavement condition. It is a scored metric ranging from 0 to 100, where 0 indicates the most severe pavement deterioration and 100 represents the optimal pavement condition. In this study, the PCI is employed as the primary indicator for assessing pavement condition.