—Roadway is one of the most crucial transportation modes to cater to inland movement within a country. The agency mandate is to design, construct, and maintain the road to sustain the traffic up to its design life without further strengthening. However, some factors are affecting the performance of the pavement. Most pavements start to show some traces of deterioration after construction and opening to traffic , but once neglected, the distress porti ons would be aggravated with corresponding increasing maintenance cost. Thus , the road's maintenance has to be carried out at the place, right schedule, right quality , and at the least cost . Since there are different maintenance alternatives, the best strategy has to be chosen following the road's condition and the severity of the damage. To select the best maintenance alternative, calculations on the pavement layer's property are performed. The Highway Development and Management (HDM -4) tool can do suc h measures to help decide which option is the best by evaluating the economic and structural conditions. This paper contains two significant areas that are studied. First, it was assessed the procedures followed by th e city's road authority to develop the appropriate road maintenance strategies . Questionnaire surveys and interviews are used to collect information from the city 's road maintenance departments . Second, the project analysis was performed fo r structural and e conomic comparison of different main tenance alternatives using HDM -4. In the analyses, three selected road segments are considered and collected important input data like road condition data, road network data, vehicle fleet data, est imated AADT, and International Roughness I ndex (IRI). Ther e were five maintenance alternatives have been defined , and proposed maintenance alternatives are compared. The selection is based on the deteriorated pavement, which showed the average roughness for every section of the road network, considering an analys is period of 20 years and cost stream ranking for their N et Present Value and IRR. Results indicated that using a mill and replace, and routine maintenance schedule for the selected road networks is economically viable and structurally significant. Hence, the city's road authority is recommended to apply the different maintenance strategies, providing an economical and better performance for the city's road network . Keywords - Appropriate maintenance strategy, Average roughness, Cost stream, Economic varia tions, Maintenance alternative . I. INTRODUCTION Road pavement deterioration due to l ack of maintenance has become a pressing issue in some developing countries. The problem was presented with length, and the results of a lack of maintenance are well-defined and quantified. Nevertheless, the problem's extent is not fully recognized, and the palliative measures are not commonly understood. To the same degree, the measures required to rectify the shortcomings are under -estimated. These include the s cale of support and capacity development required, and the time -scale necessary for establishing an effective road management system. Such a system should halt road network deterioration and ensure that financial, material and human investments are made to maintain the assets' quality and value and improve the network concerning the users' demands and priorities [1]. It is assumed that the decision to carry out rehabilitation or significant maintenance on the road has been made due to a pla nning process that has identified the 'best' projects to be undertaken in the financial planning period. Such a strategy will have identifi ed roads in need of restoration and rehabilitation and evaluated them based on economic, strategic, and political criteria [2]. Pavements are a crucial component of the inland transport system. It is important to maintain the existing pavement network in its serviceable condition within the available resources. Based on a relative perceived urgency of pavement repair, engineers and managers can prioritize and sc hedule the maintenance of affected pavement sections. Some decision -making methods have been introduced and implemented under the Pavement Management System (PMS) study to prioritize paveme nt maintenance activities [3]. Some age ncies used the Pavement Management Application that consists of the HD -4 Software and the interface built in the central repository for all network -level data required for the Pavement Management System [4]. On the other hand, an example of a well -developed system has been shown based on the current global HDM 4 model, which can be used for Project Analysis which allows users to assess the physical, functional, and economic viability of specified project alternatives by comparison against a base case, or a without -project alternative, also HDM -4 calculates the economic indicators like NPV, IRR, etc. for every option of the maintenance strategies for the projected analysis period [ 5]. Journal of Xidian University VOLUME 14, ISSUE 9, 2020ISSN No:1001-2400 http://xadzkjdx.cn/https://doi.org/10.37896/jxu14.9/084 776 In Addis Ababa, roads are b eing maintained without assessing the physical, functional, and economic feasibility between different types of road maintenance alternatives, also without calculating economic indicators for every option of maintenanc e strategies for the projected analysi s period, which in turn makes it difficult to know which maintenance alternative is best for the specific road to be maintained. When a road pavement has deteriorated, only routine maintenance like overlay and patching is being applied. These maintenance a lternatives are not enough to maintain the city's road. A variety of maintenance alternatives should be applied following the existing road condition to choose the best maintenance alternative strategy. This paper aimed to assess the structural, functional , and economic variations in using different maintenance alternatives on several roads in Addis Ababa city as a general objective. This paper's specific goal was to identify road sections that are s tructurally deficient, affecting the service level, and es tablish Life cycle prediction on the deterioration of the selected three roads in Addis Ababa city. It was made to correlate and analyze the structural performance between different road maintenance alternatives b y pavement surface gradual change in their IRI values for the desired analysis period, to determine the projected economic level between various options of maintenance strategies using HDM -4, and to evaluate the procedures followed by the City’s Road Authority in selecting the best maintenance alte rnative for specific roads and to compare with the HDM -4. II. RESEARCH METHODS A. Study Area Three road sections were selected within the road network of Addis Ababa. First, along with Bole Airport RA to Bole Michael South Intersection . This road section is located at Bole sub -city with coordinates of 38.79118 -38.77522 longitude and 8.987268 - 8.980927 latitude, an d an elevation of 2327 meters above mean sea level . The road has a length of 2.1km and a carriageway width of 20 m with a total road Area of 84000 m2. It is also called a Ring road, where a lot of vehicles are plying to get to their destination. Second, along with Coca RA to St. Amannuel Church . This road section is located at Lideta sub -city with coordinates of 38.72991 – 38.72294 longitudes and 9.016615 – 9.027708 latitude with an elevation of 2382 meters above mean sea level. The road has a length of 2.065km and a carriageway width of 5m with a total road area of 20650 m2. It is a business area where a lot of people are moving as well as vehicle s. Third, along with Future Park RA to Meta Jacros. This road section is located at Bole sub-city with coordinates of 38.81640 – 38.82128 longitudes and 9.003893 – 9.011038 latitude elevation of 2369 meters above mean sea level. The road has a length of 1. 065km and a carriageway width of 10m with a total road area of 21300 m2. It is known as a dwelling area where there is a limited activity. B. Sample Size and Selection The sampling technique that has been used in selecting road sections was purposive sampli ng. Three road sections were chosen based on data available on road condition data; based on recent maintenance date and availability of their maintenance costs. Purposive sampli ng, also known as judgment, selective or subjective sampling , is a non -probability sampling technique. The researcher relies on his judgment when choosing population members to participate in the study. Researchers often believe tha t they can obtain a representative sample by using sound judgment, which will result in saving time and money [ 6]. For h ypothes ized questions on AACRA's Road M aintenance Practices: The samples have been selected from professionals working in Addis Ababa City Road Authority, specifically the Road construction and maintenance department, Road asset management, and Road design department. It helped collect reliable data from professionals from their theoretical and practical background and their organizational relationship to know and improve AACRA's maintenance and rehabilitation activities. In addition to the study's purpose and population size, three criteria are needed to be specified to determine the appropriate sample size: The level of precision, the level of confidence or risk, and the degree of variability in the attributes being measured [7]. There are several approaches to determining the sample size. Thes e included using a census for small populations, from a sample size of similar studies, using published tables, and applying formu las to calculate the sample size . Since this part icular study population is small, Yamane [8 ] provides a simplified formula to calculate sample sizes (Respondents: Road construction and maintenance department, Road asset management, and Road design department). Considering a 95% confidence level and P= 0.5, so, n can be calculated as shown in equation 1. n=N 1+N(ⅇ)2 …………………………………………………………………………… (1) Where : n is the sample size N is the population size e is the level of precision C. Data Collection Process The study used some data sources to produce the following necessary documents: respondents' documents and archiva l documents. The respondents' comments were obtained using a question naire from a client (AACRA). A questionnaire (Open - ended questionnaire) was developed to assess the authority using types of maintenance alternatives. The alternatives used are economical for specific roads and to know if AACRA uses economic maintenance tools like HDM -4. Likewise, a desk study was chosen as one instrument to assess and obtain actual data about using different maintenance alternatives from relevant studie s, reports, and doc uments to support the study's objectives . Archival documents were collected, mostly Road Condition survey data, Vehicle fleet and composition, Road geometry, IRI of the selected road sections, unit cost, and maintenance costs. All of these documents are obtained from Addis Ababa City Roads Journal of Xidian University VOLUME 14, ISSUE 9, 2020ISSN No:1001-2400 http://xadzkjdx.cn/https://doi.org/10.37896/jxu14.9/084 777 Authority, Road Asset Management and Maintena nce Department Offices, and WT C onsult to use as significant inputs for the analysis in the HDM -4 model. D. Data Analysis The respondents requested to express their opinion by answering agreements or disagreements on five hypothesized questions, including specif ic reasons. The question naire contains two sections, section -1 about the respondents' general backgrounds, and section two deals about Road maintenance practices of AA CRA to develop appropriate maintenance strategy. However, the respondents are asked to respond to their agreement or disagreement in five nominal scales (Likert scale) . To simplify the analysis, a comparison was performed on three scales; Agree, Neutral, a nd Disagree. The response for each of the questions is compared and presented. On the other hand, t he input data, including road network data, vehicle fleet data, maintenance standard, and proj ect analysis, are necessary for the HDM -4 analysis . They are attached to the "supplementary materials" section. Five maintenance standards were defined which have been assigned for each road section; these are: Routine Maintenance (base a lternative), Mill and Replace, Crack sealing, Reconstruction, and Sc heduled Asphalt Overlay and Patching [9]. Project analysis is used to assess the physical, functional, and economic feasibility of specified project alternatives by comparing a base case or a without -project alternative. The key results of the analysis are indicated below [10, 11]: 1. Life cycle costing of pavem ent structural performance . 2. Prediction of road deterioration. 3. Estimation of road user costs (vehicle operating costs, travel time, and accidents). 4. Modeling of road works effects and the costs of these to the road administration. 5. Calculation of economic or financial benefits from comparisons of the project alternatives. This approach aimed to determine which project alternative is most cost -effective and structurally significant. The p roject analysis wa s conducted for the three road network defined above. It includes the following key processes; generally , consists of four steps:  Define project details  Specify alternatives  Analyze projects  Generate reports The first part, which was defining project detail, cont ains four parts. These are the g eneral part, select sections, and choose vehicles and define normal traffic. In the general part, the analysis starting year and the analysis period was defined. In t his case, the analysis starting year is 2020, and the analysis period considered is 20 years. The o ther essential parts are the road network and vehicle fleet data, which are selected and defined . In the next two parts, sections to be analyzed and vehicle were selected. Finally, normal traffic data is defined by providing the initial composition by the percentage of the total AADT and each vehicle's growth rate as an annual percentage increase. The second part was specifying alternatives to be analyzed in terms of section or project analysis. In this case, the investigation by section was chosen since it is needed to define several options for each section. Besides, f or each road section, four alternatives are assig ned four maintenance standards . The third part was to analyze the projects. It includes s pecifying the comparisons to be undertaken, such as the discount rate, choices about which car life model to use, what road safety analysis to be conducted, and whether or not to perform car emissions analysis and energy balance analy sis and run the analys is. The outputs from the HDM -4 analysis are produced under Generate Reports/Select Reports. The assigned maintenance alternatives were compared, and the best output is chosen after comparing their NPV and average roughness (IRI). III. RESULTS HDM -4 generates many reports like average roughness by section, economic analysis summary, economic indicator summary, road work summary by project, and section. From these, some of the selected essent ial reports are discussed below: 1. Deterioration/Work Effect R eports: Average Roughness by Section This report shows Average roughness (IRI) vs. Year for each alternative for the analysis period 2020 to 2039. A. Bole Airport RA to Bole Michael South Intersection A.1 (B to B: Section -1) The road network Bole airport to Bole Michael south intersection is divided into tw o sections. The deterioration or work effect report of section -1 is shown in f igure 1 , indicating the average roughness in m/km vs. analysis year. Journal of Xidian University VOLUME 14, ISSUE 9, 2020ISSN No:1001-2400 http://xadzkjdx.cn/https://doi.org/10.37896/jxu14.9/084 778 Fig. 1 Average Roughness (IRI): B to B: Section -1 From the above Roughness vs. Year figure, it can be seen that mill and replace (yellow color ) is the best alternative since most of the years (15 years), IRI falls below 4, which is very good in terms of riding quality and structural viability. A.2 (B to B: Section -2) The deterioration or work effect report expressed as average roughness (m/km) vs. the analysis year for the road network (Bole Airport RA to Bole Michael south intersection) for section -2 is shown in figure 2 below. Fig. 2 Average Roughness (IRI): B to B: Section -2 Also, for this section, the above figure shows Mill and Replace is the best alternative. B. Coca RA to St. Amannuel Church B.1 (C to S: Section -1) The road network Coca RA to St. Amannuel church was divided into two sections. Figure 3 shows the pavement deterioration or work effect report of the section expressed in terms of average roughness in m/km vs. analysis year. 024681012141618Average Roughness (m/Km) YearBase Alternative Crack Sealing Mill and Replace Reconstruction 024681012141618Average Roughness (IRI) YearBase Alternative Crack Sealing Mill and Replace ReconstructionJournal of Xidian University VOLUME 14, ISSUE 9, 2020ISSN No:1001-2400 http://xadzkjdx.cn/https://doi.org/10.37896/jxu14.9/084 779 Fig. 3 Average Roughness (IRI): C to S: Section -1 For this sectio n, the above figure shows both Mill and R eplace and scheduled routine maintenance (patching and overlay) are the two best alternatives. Mill and Replace are better than Scheduled routine maintenance comparatively since it falls under IRI value 4 for most analysis years . B.2 (C to S: Section -2) Fig. 4 Average Roughness (IRI): C to S: Section -2 For this par ticular section, s cheduled routine maintenance (patching and overlay) is likely the best alternative since, in most of the analysis period, consistent IRI value is shown (under 2), which is good. However, at the start of the analysis year, it offers a significant IRI value, it starts to decrease eventually until it gets to an IRI value of 2. C. Future Park RA to Meta Jacros C.1 (F to M: Section -1) Unlike the previ ously discussed road networks, this road section and Future park RA to Meta Jacross, composed only one section. The deterioration or work effect report of this single se ction road network is shown in Figure 5 , showing the average roughness in m/km vs. analysis year. 0246810121416 2020 2022 2024 2026 2028 2030 2032 2034 2036 2038Average Roughness (IRI) YearBase Alternative Mill and Replace Patching and Overlay Reconstruction 02468101214 2020 2022 2024 2026 2028 2030 2032 2034 2036 2038Average Roughness (IRI) YearBase Alternative Mill and Replace Patching and Overlay ReconstructionJournal of Xidian University VOLUME 14, ISSUE 9, 2020ISSN No:1001-2400 http://xadzkjdx.cn/https://doi.org/10.37896/jxu14.9/084 780 Fig. 5 Average Roughness (IRI): F to M: Section -1 This road network is a single section, as we can observe from the above graph, s cheduled routine maintenance (patc hing and overlay), and Mill and R eplace indicate d the best result; both are under the IRI value of 4 for the most of the analysi s period. Still, comparatively s cheduled routine maintenance is the best approach from all of the alternatives since almost from starting the analysis period, it indica ted an IRI value of 2. 1. Cost Stream Reports: Economic Indicator Summary In the Economic indicator summary, the Net P resent Value (NPV) and Internal Rate of R eturn (IRR) for all four alternatives are shown in a tabular format together with all three road n etworks and their road sections. Besides, a n increase in agency costs and a decrease in user costs are also shown. The currency is expressed in million Ethiopian Birr . A. Bole Airport RA to Bole Michael South Intersection (B -B) The economic indicator summary and NPV and Internal Rate of R eturn for the four alternatives for the road network Bole Airport RA to Bole Michael (section -1) are shown in Table I . TABLE I ECONOMIC INDICATOR SUMMARY : B TO B: SECTION -1 Alternative Present Value of Total Agency Costs (RAC) Present Value of Agency Capital Costs (CAP) Increase in Agency Costs (C) Decrease in User Costs (B) Net Exogenous Benefits (E) Net Present Value (NPV ) NPV/Cost Ratio (NPV/RAC ) NPV/Cost Ratio (NPV/CAP) Internal Rate of Return (IRR) Base Alternative 8.203 8.203 0.000 0.000 0.000 0.000 0.000 0.000 0.000 MILL AND REPLACE 5.833 5.833 -2.370 2.520 0.000 4.890 0.838 0.838 14.6 (2) CRACK SEALING 0.485 0.000 -7.718 -897.097 0.000 -889.379 -1,834.440 zero cost No Solution RECONSTRUC TION 8.688 8.688 0.485 -154.872 0.000 -155.357 -17.882 -17.882 -27.7(2) Figure in brackets is the number of IRR solutions in the range -90 to +900 Likewise, the e conomic indicators for the four alternatives for the section -2 of the road network Bole Airport RA to Bole Michael intersection are illustrated as a tabular format in Table II. 02468101214 2020 2022 2024 2026 2028 2030 2032 2034 2036 2038Average Roughness (IRI) YearBase Alternative Mill and Replace Patching and Overlay ReconstructionJournal of Xidian University VOLUME 14, ISSUE 9, 2020ISSN No:1001-2400 http://xadzkjdx.cn/https://doi.org/10.37896/jxu14.9/084 781 TABLE III ECONOMIC INDICATOR SUMMARY : B TO B: SECTION -2 Alternative Present Value of Total Agency Costs (RAC) Current Value of Agency Capital Costs (CAP) Increase in Agency Costs (C) Decrea se in User Costs (B) Net Exogenous Benefits (E) Net Present Value (NPV ) NPV/Cost Ratio (NPV/RAC ) NPV/Cost Ratio (NPV/CAP) Internal Rate of Return (IRR) Base Alternative 12.019 12.019 0.000 0.000 0.000 0.000 0.000 0.000 0.000 MILL AND REPLACE 8.822 8.822 -3.196 65.032 0.000 68.228 7.734 7.734 33.6 (1) CRACK SEALING 0.829 0.000 -11.190 - 1,290.07 0 0.000 -1,278.880 -1,543.269 zero cost No Solution RECONSTRUCT ION 13.141 13.141 1.122 -171.677 0.000 -172.799 -13.150 -13.150 -36.9 (1) Figure in brackets is the number of IRR solutions in the range -90 to +900 B. Coca RA to St. Amannuel Church (C -S) The economic indicator summary and NPV and Internal Rate of R eturn for the four alternatives of the road section along with Coca RA to St. Amannuel church (section -1) are shown in Table III. TABLE IIIII ECONOMIC INDICATOR SUMMARY : C TO S: SECTION -1 Alternative Present Value of Total Agency Costs (RAC) Present Value of Agency Capital Costs (CAP ) Increase in Agency Costs (C) Decrease in User Costs (B) Net Exogenous Benefits ( E) Net Present Value (NPV ) NPV/Cost Ratio (NPV/RAC ) NPV/Cost Ratio (NPV/CAP) Internal Rate of Return (IRR) Base Alternative 9.281 9.281 0.000 0.000 0.000 0.000 0.000 0.000 0.000 MILL AND REPLACE 4.799 4.799 -4.482 134.608 0.000 139.090 28.984 28.984 No Solution RECONSTRUCT ION 7.546 7.546 -1.735 61.865 0.000 63.600 8.428 8.428 3.7 (2) PATCHING AND OVERLAY 16.859 16.859 7.578 62.800 0.000 55.222 3.276 3.276 678.4 (1) Figure in brackets is the number of IRR solutions in the range -90 to +900 Also, in Table IV below, the economic indicators used in comparing the give n four alternatives for section -2 for the road section along with Coca RA to St. Amannuel church are indicated . TABLE IV ECONOMIC INDICATOR SUMMARY : C TO S: SECTION -2 Alternative Present Value of Total Agency Costs (RAC) Present Value of Agency Capital Costs (CAP) Increase in Agency Costs (C) Decrease in User Costs (B) Net Exogenous Benefits (E) Net Present Value (NPV ) NPV/Cost Ratio (NPV/RAC ) NPV/Cost Ratio (NPV/CAP) Internal Rate of Return (IRR) Journal of Xidian University VOLUME 14, ISSUE 9, 2020ISSN No:1001-2400 http://xadzkjdx.cn/https://doi.org/10.37896/jxu14.9/084 782 Base Alternative 5.105 5.105 0.000 0.000 0.000 0.000 0.000 0.000 0.000 MILL AND REPLACE 2.710 2.710 -2.395 -5.532 0.000 -3.138 -1.158 -1.158 No Solution RECONSTRUC TION 4.211 4.211 -0.894 26.542 0.000 27.436 6.516 6.516 No Solution PATCHING AND OVERLAY 9.317 9.317 4.212 27.370 0.000 23.158 2.486 2.486 465.4 (1) Figure in brackets is the number of IRR solutions in a range –90 to +900 C. Future Park RA to Meta Jacros The economic indicator like N et Present Value (N PV) and I nternet Rate of Return (IRR) are shown in Table V for this single section. TABLE V ECONOMIC INDICATOR SUMMARY : F TO M: SECTION -1 Alternative Present Value of Total Agency Costs (RAC) Present Value of Agency Capital Costs (CAP) Increase in Agency Costs (C) Decrease in User Costs (B) Net Exogenous Benefits (E) Net Present Value (NPV ) NPV/Cost Ratio (NPV/RAC ) NPV/Cost Ratio (NPV/CAP) Internal Rate of Return (IRR) Base Alternative 4.284 4.284 0.000 0.000 0.000 0.000 0.000 0.000 0.000 MILL AND REPLACE 3.014 3.014 -1.270 -7.291 0.000 -6.021 -1.998 -1.998 10.4 (2) RECONSTRUCT ION 4.268 4.268 -0.016 -43.456 0.000 -43.440 -10.177 -10.177 No Solution PATCHING AND OVERLAY 26.999 26.999 22.715 53.327 0.000 30.612 1.134 1.134 145.7 (1) Figure in brackets is the number of IRR solutions in the range – 90 to +900 IV. DISCUSSION From the HDM -4 output results in the above tables, the alternatives are compared based on the N et Present Value (N PV) value s. The one with the most significant N et Present Value (N PV) value is taken as the best alternative. 4.1. Bole Airport RA to Bole Michael South Intersection: For section 1, Mill and Replace is the best alternative based on N et Present Value . This result confirm ed with the comparison of the alternatives based on average roughness. Also, for section -2, Mill and Replace could be seen as the best alternative. This result also confirm ed with the comparison of the options based on average roughness. On the other hand, section -1, the suggested maintenance strategy by ACCRA, is the application of asphalt overlay, but contrary, the HDM -4 result for the same section suggested M ill and Replace as the best alternative . Therefore, while considering different cost schemes like long -term agency cost, road user costs, mill and replace, ha d found to be the best alternative for the given analysis period of 20 years. In section -2, the suggested maint enance strategy by AACRA was patching plus ( +) overlay, but the HDM -4 result for the same section suggest ed Mill and R eplace. So, Mill and R eplace's application is the most viable and structurally capable maintenance alternative for the whole road section . 4.2 Coca RA to St. Amannuel Church: For section -1, Mill and Replace is the best alternative based on N et Present Value . This result also confirm ed with the comparison of the alternatives based on average roughness. Section -2, reconstruction of the road (rehabilitation) is the best Journal of Xidian University VOLUME 14, ISSUE 9, 2020ISSN No:1001-2400 http://xadzkjdx.cn/https://doi.org/10.37896/jxu14.9/084 783 alternative but based on a comparison against average roughness, scheduled patching and overlay was a bit better than reconstruction. In section -1, ACCRA's suggested maintenance strategy was patchi ng plus ( +) overlay, but the HDM -4 resu lt for the same section suggested M ill and R eplace was the best alternative . Therefore, while considering different types of costs like long term agency cost, road user costs, mill and replace, ha d found the best alte rnative for the given analysis period of 20 years. While in section -2, the suggested maintenance strategy by AACRA was a reconstruction of pavement (rehabilitation), and the HDM -4 result for the same section also suggest ed reconstruction of the road. 4.3 Future Park RA to Meta Jacros: This road section indicated that s cheduled asphalt overlay and patching is the best alternative based on N et Present Value (NPV). Also, it confirm ed that this alternative is viable based on the average roughness index . It suggested a maintenance strategy by AACRA, such as asphalt overlay ( i.e., responsive routine maintenance). The analysis of the HDM -4 supported the mentioned strategy by AACRA through s cheduled patching and overlay . It implies that AACRA would have been mor e economical if they have a schedule and apply the routine maintenance activity once a year. 4.4. On Hypothesized Questions on Road Maintenance Practices of AACRA: Most of the pavement treatment types applied by A ddis Ababa City Road Authority (A ACRA ) are asphalt overlay and patching along the three studied sections . In 2008 E.C or 2016 G.C, the authority has implemented a pilot project on anti -rut treatment type on the Old Post office road to prevent rutting. The treatment type was applied in the section with a high grade(slope). It was observed that the sudden braking force from the heavy trucks was the primary factor causing a problem of pavement rutting. Likewise, AACRA is planning to perform preventive treatment type on succeeding upcoming projects , while other road sections, Mill and R eplace treatment type, will be implemented in forthcoming years . It was known that the road authority had purchased a Milling machine to replace the previous method of removing defected pavement by labor. Among the different pavement maintenance treatment types that can be used, most respondents agreed that AACRA is implementing patching potholes and asphalt overlay. Besides, AACRA is experimenting with different kinds of pavement treatm ent types such as Anti -rut and Mill and R eplace ; most of the AACRA's pavement maintenance projects are sealing cracks, patching potholes, and asphalt overlay . But, t hese treatments are not adequate to maintain the city's road in good condition. It was also observed that AACRA did not a pply specific maintenance treatment selection techniques, which are mandatory for recommending specific and cost -effective remedial maintenance measures. More so, most respondents agree d that AACRA currently not using different tools or Software to develop the appropriate pavement maintenance strategy. There is various S oftware used by road agencies worldwide to choose the best maintenance treatment method among different maintenance strategies . One of them is HDM -4, which calculates economic indicators like N et Present Value (NPV) , Internal Rate of Return (I RR) for the maintenance strategies within the projected analysis period. The most beneficial maintenance option will be one that gives the maximum economic return. Hence, considering the study results , AACRA has to strengthen the pavement evaluation method to assist in the treatment selection strategy . It has to determine alternative treatment options and sort out cost feasibility, treatment's ability to the pavement's functional and structural conditi on while also meeting any future needs or require ment s. It is also suggested that Addis Ababa City Road Authority ( AACRA ) has to regularly carry out routine road maintenance activities known by its relatively inexpensive and significant cost savings method s. V. CONCLUSION Currently, Addis Ababa City Road Authority ( AACRA ) applies patching, asphalt overlay, and reconstruction as a maintenance strategy on the three road sections studied but did not apply routine maintenance, such as crack sealing , de-clogging of the drainage system, and other routine maintenance activities . Besides, t he road authority does not have a formal standard approach of intervention; instead, maintenance work for specific work is based on severity level . The above paper also shows that AACRA currently does not have any software or tools to come up with the appropriate maintenance activities that offers the alternative that is economical or not. The result from HDM -4 shows that applying Mill and R eplace is more economical than overlay even though it has more initial cost than the overlay . At the end of the analysis period of 20 years , Mill and R eplace provides more excellent N et Present Value (N PV). Hence, the result obtained from HDM -4, scheduled routine ma intenance is economically viable and structurally efficient in reducing pavement cracks and keeping the road in good condition. The softw are result also shows that the Mill and R eplace reduces roughness value by a more significant degree than an asphalt overlay. ACKNOWLEDGMENT The authors are so grateful to the Ethiopian Roads Authority (ERA) for providing the licensed HDM -4 Software to obtain a genuine and reliable output of the study . Journal of Xidian University VOLUME 14, ISSUE 9, 2020ISSN No:1001-2400 http://xadzkjdx.cn/https://doi.org/10.37896/jxu14.9/084 784