Evaluating the Urban Sustainable Development on the Basis of AHP: A Case Study for Riyadh City

This study aimed to evaluate the urban sustainable development for Riyadh city on the basis of the analytic hierarchy process (AHP). This process is very important to the future development of the urban areas. In order to achieve this goal, indicators of sustainability were defined according to the urban level; and then categorized into three indexes (level of development, development coordination extent, and development potential). The results indicated that the index of Development potential had the greatest priority in comparison with the other indexes.


Introduction
Increasingly, the world is becoming an urban area.According to Schell and Ulijaszek (1999) and Alpopi, Manole, & Colesca (2011), approximately 65% of the world's population is expected to live in cities by 2025.Hence, this reflects the importance of the urban sustainable development.Furthermore, the development of social, economic and environmental aspects of urban systems reflects the level of urban sustainable development (Hai-yang, Hai-yang & fang, 2009;Thinh et al., 2002;Kondyli, 2010).The concept of sustainable development was defined by the World Commission on Environment and Development (WCED) as "development that meets the needs of the present, without compromising the ability of future generations to meet their own needs" (WCED, 1987).
Measuring the sustainability in civilized areas, which are critical engines for practicing the local socioeconomic activities, become an outstanding challenge for the environmental managers and decision-makers (Moussiopoulos et al., 2010;Li et al., 2009).The idea of sustainable development was formulated in order to meet the growing understanding regarding the several strategic relationships between the different urban processes such as the social and economic development; global, regional and local environmental problems; the increase in population and urbanized built-up areas (Malkina-Pykh, 2002;Alpopi, Manole, & Colesca, 2011).
The analytic hierarchy process (AHP) has the non-structural advantage as a multi-criteria judgment method, which is actually valid for evaluating the urban sustainable development.The AHP model combines both subjective and objective assessments in the form of combination weight based on ratio scales derived from simple pairwise comparisons.However, this model requires three steps: structuring the hierarchy, conducting pairwise comparisons so as to define priorities, and gathering the priorities related to the decision's alternatives or options (Schoner & Wedley, 1989;Stam, & Silva, 2003).
Cities are construction systems restricted by various social, systematic and environmental factors, with countless conflicts and interactions underlying these factors (Ma & Wang, 1984;Li et al., 2009;Kondyli, 2010).However, the High Commission for the development of Riyadh city, stemming from its strategy that aims to modify the services provided for the Built-up area, has established an integrated coordinating program for providing public services within the municipality of Riyadh.Of course the program aims to provide general services and fill out the existed inefficiencies.In addition, the program aims to define the timeline required for providing the public services within the city alongside with creating a modern database that involves the entire public services in terms of their locations and the owned and planed lands relying on the geographic information systems.This in turn represents a supportive tool for the relevant decision makers (Ministry of Municipal Affairs and Projects, 2000).Thus, the evaluation of urban sustainable development indicates a very significant clue to the future development of Riyadh City.

Methodology
This study adopted an analytical, descriptive method by using the analytic hierarchy process (AHP).This was performed through selecting the most adequate index depending on a number of criteria.However, the related literature was reviewed (Hai-yang, Hai-yang & fang, 2009).Depending on the analytic hierarchy process, the current researcher developed a questionnaire that was introduced to a group of specialists.Then, data were collected and the results were inferred which assisted in concluding the recommendations offered at the end of this study.

Participants
The study was applied to a group of experts, who comprises five specialists, working in the field of urban sustainable development.The study instrument was administered on those specialists in order to verify the index.

Analytic Hierarchy Process (AHP)
The Analytic hierarchy process (AHP) is a method that helps the decision maker in evaluating the complicated problems and issues.Furthermore, this method contributes in identifying numerical values for the objective stimuli related to the given problem through conducting comparisons between the various criteria that affect the problem directly.This method is crucial since it assists the decision makers in observing the continuous interaction between the elements of the complicated problem.However, this in turn assists them in defining the problem's elements and setting its priorities depending on their relevant knowledge and experiences as well as the desired goals (Satty, 1990;Stam, & Silva, 2003).
In order to perform the analytical hierarchy process, it is necessary to undertake the following steps (Saaty, 2008): a) Identifying the problem by identifying the goal.b) Identifying the criteria that affect and influence the problem.c) Identifying the suggested alternatives or solutions that will be compared and differentiated.d) Constructing the hierarchical model, including the higher level that represents the desired goal; the middle level that represents criteria; sub-criteria that influence the problem; and the lower level that represents the suggested alternatives and solutions that will be compared and differentiated in order to solve the problem.
e) Collecting data, noting that it is required here to identify the personal judgments of the decision makers, the experienced people and researchers who are familiar with the problem in order to provide solutions for it.This is accomplished by conducting personal interviews or special questionnaires related to the analytical hierarchy.
f) Designing pair-wise comparisons matrix, where elements are compared by two-way method for each trait.
g) The pair-wise comparison starts from the top of the hierarchical model, which represent the, as mentioned before, the highest level in the model (the goal).The beginning is done by comparing the criteria relative to the goal where this comparison follows the pair-wise method by comparing between two criteria for the same goal followed by making a shift toward another two criteria to select the goal.
There are three criteria allocated to the problem (C1, C2, C3).The matrix is designed as shown in the Table 1 below.

Instrument
In order to achieve the goal of the current study, a questionnaire based on the analytic hierarchy process was developed by following the steps below: a) The most important adopted criteria were defined to evaluate the urban sustainable development, and then they were used to differentiate between the indexes.The most important adopted criteria were defined to be evaluated according to the criteria (index) mentioned in the previous step.These criteria were set based on reviewing the previous literature and early studies related to urban sustainable development (Thinh et al., 2002).The criteria reported in the study by Hai-yang & fang (2009) were used.These criteria and their descriptions are shown in Table 2. b) Nine-point scale was used for applying the pair-wise comparisons between the criteria from one hand, and between the alternatives from the other hand based on each criterion.Table 3 shows the graduation in the nine levels.
Table 3. Fundamental scale for pair-wise comparisons

Verbal scale Numerical Rating
Equally important 1

Equally to moderately 2
Moderately more important, likely or preferred 3 Moderately to strongly 4 Strongly more important, likely or preferred 5

Strongly to very Strongly 6
Very strongly more important, likely or preferred 7 Very strongly to extremely 8 Extremely more important, likely or preferred www.ccsen c) T (t

The An
The Exper Hierarchy

Pair-W
The Analy the relative

Conclusion
The results indicated that the Development potential criterion had the greatest priority since its relative significance amounted to 63.6%.The Level development criterion came in the second rank in terms of the relative significance as compared to the other criteria while the Development coordination criterion ranked lastly.
The results indicated that the Economic development level alternative had the greatest priority according to level of development criterion.The Resources and environmental protection as compared to the other was the second alternative followed by the Population growth level alternative while the Social development level alternative ranked lastly.
The results indicated that the Social economy coordination alternative had the greatest priority according to the Development coordination extent criterion.The second alternative was the Environmental, economic coordination followed by the Urban-rural relationship coordination alternative which ranked lastly.
The results indicated that the Management and adjustment potential alternative had the greatest priority according to the Development potential criterion.The second alternative was the Economic development potential.The third alternative was the Resources development potential followed by the Education and scientific support ability and the Environmental protection potentials alternatives respectively; while the Social development potential alternative ranked lastly.
In light of the results revealed in this study, the researcher recommends the following: a. Using the AHP model for evaluating the urban sustainable development since it has a special advantage as a multi-criteria evaluation method as well as it is very suitable for evaluating Riyadh urban sustainable development.Moreover, this study proposes the Development potential index with a greater priority for evaluating Riyadh urban sustainable development.
b. Conducting more similar studies with using more indexes to enhance the Riyadh urban sustainable development.
c. Enhancing studies that adopt the analytic hierarchy theory because of its importance in improving the effectiveness of the decision-making process, especially in Evaluating the Urban Sustainable Development. Fig Figure 4 indexes" which are: economic development potential, social development potential, educational and scientific support ability, environmental protection potential, resources development potential, management and adjustment potential

Table 2 .
Evaluation indexes of urban sustainable development