## 2 Sustainable Approach to Nonurban Road Network Maintenance Management-- Materials and Methods
### Monitoring and Control Process of Nonurban Road Network Maintenance Management  
Regardless of the nonurban road maintenance management plan, if the monitoring and control process is not carried out during the annual maintenance, it is not possible to obtain information on the progress and efficiency of the maintenance management system. According to [PERSON] [30], actual project progress is used to update the schedule and budget to determine the percentage of complete activities of the project and to determine how the uncompleted portion of the project will be affected. Therefore, an integral part of the proposed maintenance management model for nonurban road network is the management process of monitoring and control, which is carried out through comparison of the priority maintenance plan and the actual maintenance of nonurban roads, determination of actual progress and performance indicators, execution of corrective actions if it is necessary and creating an efficient maintenance system for the nonurban road network (Figure 7). Maintenance monitoring and control process is based on integration of TOPSIS as the multiciteria decision-making method and Earned Value Analysis (EVA) as the monitoring and control method through the sub-model for maintenance monitoring and control for the nonurban road network, also named as Sub-model 3. EVA is based on three key variables, i.e., progress and performance indicators which represent fundamentals of its analysis: budgeted cost of work performed (BCWP), budgeted cost of work scheduled (BCWS) and actual cost of work performed (ACWP) [31]. From these three data, it is possible to obtain the remaining indicators, such as schedule variance (SV) as the time deviation from the plan calculated as the difference between BCWP and BCWS, cost variance (CV) as the cost deviation from the budget calculated as the difference between BCWS and ACWP and time variance (TV) as the amount of time the project is ahead or behind, expressed in time units [2]. It is evident that the EVA, in comparison with traditional methods of monitoring and control which are based only on the comparison of the planned and executed state, also takes into account the earned value, which is the specificity of this method and the reason for its application within the maintenance management model for the nonurban road network. Sub-Model for Maintenance Monitoring and Control for Nonurban Road Network  
The sub-model for maintenance monitoring and control is based on the previously described Earned Value Analysis (EVA) as one of the most effective tools for monitoring and  
Figure 6: Concept of sub–model of nonurban road priority ranking. Figure 7: Summary view of the monitoring and control management process. control, thus enabling closing of the loop in the PDCA cycle [32], which forms an integral part of the proposed maintenance management model for the nonurban road network. According to [PERSON] [30], monitoring and control is an iterative process to compare actual and planned performance, establish cost and time estimates upon completion, and, if necessary, take preventive and corrective actions based on such estimates. Since the proposed model is based on optimization according to the maintenance cost criterion (C7), the deviation from the plan can be observed through the value of road maintenance index (MRI) as the ratio of budgeted cost of work performed (BCWP) and actual cost of work performed (ACWP). In that case, it is necessary to take corrective measures of reallocation of financial resources only for those nonurban roads for which the MRI value is not within the optimal limits between 0.9 and 1.1. From that reallocation of financial resources, it is possible to obtain a new maintenance cost (NMC) as follows:  
\[\text{NMC}=\frac{\text{AB}\ -\ \text{BCWP}}{\text{MRI}} \tag{3}\]  
where AB is the budget allocated according to the results of the TOPSIS method in relation to the total annual budget intended for nonurban road maintenance activities.