Revision of Sustainable Road Rating Systems: Selection of the Best Suited System for Hungarian Road Construction Using TOPSIS Method

Abstract

There are a number of sustainable and environmentally friendly techniques and methods currently available in the construction industry. To promote sustainable development, different rating and certificating systems that evaluate the level of sustainability during the development of infrastructure construction projects have been developed. The aim of the research presented in this paper was to examine the applicability of sustainability rating systems in Hungary and find the most suitable option. After a review of commonly used rating systems, i.e., Greenroads, GreenLITES, I-LAST, Envision, and INVEST, the most suitable existing rating system is selected with the help of the Technique for Order Preference by Similarity to the Ideal Solution (TOPSIS) mathematical decision analysis method. This was achieved by utilizing 12 categories of input data (weights) analyzed through TOPSIS. The input data (weights) of the TOPSIS method were determined by a small research group of industry experts and academic professionals based on Hungarian practices and methodology. As a result of the calculation, the study found that the Envision rating system satisfies the criteria best, closely followed by Greenroads.

1. Introduction

It is widely agreed that the construction industry has one of the most significant impacts on our environment, contributing significantly to air pollution, resource depletion, waste generation, global warming, and climate change. Energy-intensive processes are required to produce and build the raw materials for structures, and the finished structure influences the aesthetics of the environment and, in the case of transportation, can affect the ecosystem of natural habitats, water quality, and noise pollution [1,2,3]. To optimize these factors, the application of sustainable development has also become important in the construction sector. Recently, sustainable development has become an economic issue for business, as long-range economic models have to include rising energy costs and will soon have to include CO₂ emissions permits as well. These items represent new risks but also an opportunity to change technological and operational trade-offs, especially in the built environment or transport-related sectors [1].

The construction industry is taking huge steps toward supporting a wide range of environmentally friendly strategies and technologies and promoting green building practices. Structural engineering plays a leading role in the development of green assessment systems, such as Leadership in Energy and Environmental Design (LEED) and the Green Globes and Building Research Establishment Environmental Assessment Method (BREEAM), which helps stakeholders to identify green practices and assess progress towards sustainability. Despite the popularity of green rating systems in civil construction over the last 20 years, they have become less widespread internationally in road construction [4]. Nevertheless, many systems have been developed, largely in the United States. These rating and evaluation systems have generally been established by trusted governmental and private organizations working with academia. They analyze, evaluate, and sort out the existing facilities. In general, when a project is evaluated using a certification system, it should meet certain minimum, mandatory prerequisites or a minimum score in the evaluation. In any of the rating systems, self-assessment takes place without the involvement of a third party—a certifier—where the goal is to measure and monitor sustainability in order to define future development goals and analyze and communicate sustainability for the benefit of the society. Ratings of segments (categories) and subclasses are collected and compared. Certification and rating systems typically include general components that are part of the certification tools: systematic and strategic environmental performance, water, energy, materials, safety, education, and innovation. Each rating system includes a specific weighting methodology, which differs depending on the system.

Achieving sustainable planning and design is becoming essential in Hungary (due to EU directives). This requires changes on the capital investor and political side. While most of the techniques and practices are available, there is a need for customers to be committed to sustainable practices. A low demand can be a result of fear of lower levels of performance (warm mix asphalt (WMA), recycled asphalt pavement (RAP)) or the extra cost and extra work hours caused by sustainable design. Therefore, well-structured regulation or incentive tools are needed to spread the requisite techniques and mindsets. Different “green” objective rating systems can help increase the level of sustainability in both design and implementation. Therefore, the application of a rating system is very significant in Hungary with regard to the promotion of sustainable development and keeping up with the leading European countries.

This study focuses on the Greenroads, I_LAST, Envision, GreenLITES, and INVEST systems and shows how different national systems were developed. The aim of the paper is to select the system that is most suitable for the promotion of sustainability in Hungarian road construction.

2. Literature Review

In recent decades, in Hungary, as in many other countries, a lot of research, regulation, and innovation has been conducted to make the construction industry more sustainable. As a member of the European Union, Hungary’s construction regulation complies with European regulations. Based on this, project developments often start with green public procurement (GPP) and are examined by cost-benefit analysis (CBA) and environmental impact assessment (EIA). Within the evaluation of EIA, an examination of the land use, interference with ecosystems, changes in natural capitals, and changes in ecosystem services is extremely important for maintaining the rich biodiversity of the country. Therefore, some of the available sustainable evaluation methods are used in Hungary; however, many of the available other tools are typically not or are rarely involved in the project development phase. For instance, the energy consumption throughout the life cycle of a project, the costs for the whole life cycle in the project development phase and the amount of recycled-material usage are often not considered in practice [5]. The use of local materials is important in the Hungarian practice; however, this is more likely caused by cost implications, which is still the most important aspect of the decision-making process in the country.

Based on the abovementioned issues, in order to make Hungarian construction practices more sustainable and promote sustainable long-term strategies, the use of a green rating system or national sustainable indicators is required. For this reason, the Hungarian Road Administration conducted a study in 2015 [5] with the title “Sustainable pavements and highways: An analysis of green roads rating systems”. This internal study reviewed international practices, analyzed the methods and tools, and narrowed down the suitable rating systems. This paper further analyzes these systems; a comparison of these system with the TOPSIS method is also provided which has not been conducted before.

This section presents the Greenroads, GreenLITES, I-LAST, Envision, and INVEST rating systems, mentions some other important, frequently used systems, and presents the commonly used ways to develop national rating systems or a sustainable set of indicators. A more detailed literature review can be found in Appendix A, where the previously selected rating and certificating systems are presented based on their manuals.

2.1. Greenroads

The Greenroads rating system was developed by the University of Washington in 2007, with the participation of more than 100 professionals. It is primarily applicable to the US environment but can be applied worldwide. The system is project-based and can be used to certify projects to support sustainable practices [6]. The evaluation has two parts, project requirements and voluntary credits. The project essentially requires compliance with technical and legal requirements and consists of some basic, forward-looking but not necessarily legally binding parts. There are currently four certification levels: Bronze (40-point minimum); Silver (50-point minimum); Gold (60-point minimum); Evergreen (80-point minimum) [7]. With over 1100 organizations and members from 62 countries around the world and 50 states in the US, the system has been used in more than 130 different types of projects with investment beneficiaries and 50 qualified projects. It can therefore be stated that the system is highly successful.

Greenroads places great emphasis on management tools. The system is detailed enough to perform the assessment work in practice but general enough to provide a comprehensive picture of sustainability on a larger scale. The system considers the three pillars of sustainability; however, the emphasis is clearly on the environmental impacts.

2.2. I-LAST

The Illinois-Livable and Sustainable Transportation Rating System and Guide (I-LAST) rating system was developed in collaboration with the Illinois Department of Transportation and the engineering and construction community. The system aims to assess and encourage the sustainability of investments using simple tools. The system consists of a Microsoft (MS) Excel spreadsheet with a detailed description and instructions attached to it. The use of the system is voluntary and free. It is intended to be simple and quick; therefore, it has quantitative criteria. The handbook consists of a detailed system of scoring criteria which can be used to increase the sustainability of an investment. Projects are evaluated based on nine main categories, which are divided into subcategories. There is a total of 153 criteria in the system, and the number of points that can be obtained is 233 [8]. The evaluation takes into account practical aspects, which assess sustainability on the basis of the presence or absence of specific technologies and methods. Because of this, without development and continuous expansion, it may become obsolete in the medium to even short term with the development of new technologies.

2.3. ENVISION

Envision was developed through a collaboration between Harvard University Graduate School of Design and the Institute for Sustainable Infrastructure, together with a Zofnass Program for Sustainable Infrastructure. The methodology, released in 2012, was developed primarily for use in the design and project development process, but the most recent and expanded version also evaluates the processes of construction, operation, maintenance, and demolition. Envision is therefore a family of tools that covers all stages of the project life cycle. The aim of the assessment is, in addition to certification, to promote sustainability in technical, social, environmental, and economic terms using the detailed descriptions provided in the guide. The Envision manual contains goals and performance levels that the user can employ in evaluating the project. The rating system can be paired with other Envision tools, such as the Envision checklist, which is a series of yes or no questions for self-evaluation. The checklist can be useful at the beginning of project planning, when the specific performance data for the detailed assessment are still unknown [9].

Currently, both the second and third versions of the system can be used to evaluate projects [10]. Any version of Envision examines projects according to five main categories, which can be further subdivided into a total of 60 credits with a total of 1000 points. The collected data are reviewed by an independent third party, the so-called ENVISION Verifier. The system is both detailed and general enough to provide a comprehensive picture of sustainability on a larger scale; therefore, the use of the Envision system is widespread.

2.4. GreenLITES

The Green Leadership in Transportation and Environmental Sustainability (GreenLITES) rating system was developed by the New York State Department of Transportation (NYSDOT, Albany, USA) based on the LEED and Greenroads systems. The first version was released in 2008 for evaluation at the design level (GreenLITES Project Design). In 2009, a version for the evaluation of operation and maintenance strategies (GreenLITES Operations) was released. A project can be examined using 175 subcategories, which are divided into five main categories, with a total of 271 points. Depending on the amount of points earned, the project may earn one of four certification levels [11]. For the evaluation, a downloadable MS Excel spreadsheet is available. The listed aspects include several questions, for which 0–4 points can be awarded based on the guide. The purpose of the rating system is not only to evaluate projects but also to measure the NYSDOT performance itself, identify areas for improvement, and use it as a tool to show the public how they are making progress in sustainable practices [12].

2.5. INVEST

Infrastructure Voluntary Evaluation Sustainability Tool (INVEST) was established by the US Federal Highway Administration (FHWA, Washington, USA) in 2010. The system is free, user-friendly, and available online. As there is no third-party verification, it does not provide an officially accepted certificate. The purpose is to apply more sustainable solutions during self-auditing and design, as well as to guide users toward focusing on more sustainable solutions. INVEST can be used in three phases of a project, which is evaluated according to separate categories. The phases are the System Planning (SP), Project Development (PD), and Operation and Maintenance (OM) phases; however, the PD phase is the most detailed, consisting of several scorecards designed to identify the varying scope, size, and context of projects across the country [13]. The aim of the SP modules is to assess the sustainability of a greater network, such as state or region. The SP modules contain 17 criteria each, which are combined into a single scorecard. The Project Development modules evaluate the investments from the beginning of the planning, through the selection of alternatives, environmental analyses, and preparation of the final plans, to the implementation. In terms of scoring, INVEST has seven evaluation sheets for project evaluation. This approach provides flexibility, as not all conditions apply to all projects. Six of the scorecards are based on the type of project, such as paving, urban basic, urban extended, rural basic, rural extended, or scenic and recreational. A total of 33 complete criteria are defined. From these, different elements (subsets) should be fulfilled, depending on the type of project. The seventh is a unique evaluation sheet, which contains 11 basic criteria and user-selected criteria, thus allowing for an individual self-assessment of projects that do not fit well with the defined evaluation sheets [14]. The aim of the OM module is to evaluate system-level operation and maintenance activities based on their contribution to the sustainability of the transport system. There are 14 criteria in the module, with the 210 points that can be obtained divided equally between the criteria.

INVEST is, therefore, a free self-assessment tool that covers the entire life cycle of a transport facility using different worksheets, without the need for third party certification. The Scoring Guide section specifies the condition for earning points. Depending on the criterion, the condition can be qualitative or quantitative. The biggest advantage of the system is that it is also suitable for the strategic and operation-maintenance phases. It should be noted, however, that at the strategic and operational maintenance levels, the system is very general, as the effects in these phases are much more difficult to measure and delimit compared to those at the project level.

2.6. Other Rating Systems

CEEQUAL: A British rating and reward system for improving sustainability in the civil engineering and public realm. The system was developed in 2003 and has been recognized in the UK and Ireland. CEEQUAL Version 6, which provides a global benchmark for infrastructure sustainability to compare projects across markets and regions, was launched in 2019. The system conducts its evaluation according to eight main categories: Management, Resilience, Communities and Stakeholders, Land Use and Ecology, Landscape and Historic Environment, Pollution, Resources, and Transport [15]. The system also has some prerequisites that must be fulfilled at the beginning, including some issues that must be solved for certification.

Sustainable Transportation Analysis Rating System (STARS): This system was developed by the North American Sustainable Transportation Council (STC). Project credits are divided into eight categories: Integrated Process, Community, Access and Mobility, Climate and Energy, Ecological Benefit, Cost-Effectiveness, Safety and Health, and Ecological Function [16].

GreenPave: This project was developed by the Ontario Ministry of Transportation. It is a computerized checklist with four main categories: Pavement Technologies, Materials and Resources, Energy and Atmosphere, and Innovations and Design Processes [17].

Sustainability National Road Administrations (SUNRA): This project was set up by the national road administration (NRA) to measure sustainability performance in Europe in collaboration with seven countries, including Germany, Denmark, Ireland, the Netherlands, Norway, Sweden, and the United Kingdom [18].

Building for Environmental and Economic Sustainability (BE²ST): This system was developed by the Recycled Materials Resources Center (RMRC) at the University of Wisconsin College of Engineering. It provides the opportunity to assign weight based on importance and the analysis is conducted through the Analytical Hierarchy Process (AHP) [19]. For modelling, the recommended software is available for free; however, it has not been further developed. Moreover, the national databases required for the input data are missing for Hungary; introducing this system would require extensive data collection, which significantly complicates and delays the practical application.

2.7. Development of National Rating Systems—A Global Overview

Recognizing the benefits of sustainability rating systems, many countries have followed the example of the systems listed above, including South Korea, Malaysia, India, Indonesia, Iraq [20,21,22,23,24,25] and, in Europe, Italy [26]. Moreover, within the framework of the SUNRA project, Germany, Denmark, Ireland, the Netherlands, Norway, Sweden, and the United Kingdom [18] have examined the introduction of sustainability assessment systems. Literature research shows that some of these countries (South Korea, Malaysia, and India) have established their own assessment systems due to national specifics, such as climatic and environmental conditions, social needs, and national construction practices. The method of setting up the rating systems was similar in the three countries. For South Korea, Malaysia, and India, the systems were also initiated by their governments and have been requested from academia and/or transportation authorities. The methodology for creating a national evaluation system is illustrated in Figure 1 below.

While the main steps of the methods are the same, the establishment of country-specific systems after the identification of the criteria and their elements slightly differed for the three countries. According to Park and Ahn [14], in the case of South Korea, once the objectives of the green road grading system had been set, 10 industry experts (five architects and civil engineers firms and five construction firms), who had been working in the profession for at least 20 years, were asked to identify and develop the categories, indicators, and credits for the green rating. Once this was determined, expert groups of 10 construction and architecture/engineering (A/E) professionals, 9 researchers and professors, 3 government officials, and 4 business owners were interviewed for individual and group interviews to form the scoring. The participants were asked to rank measures based on their importance for establishing a South Korean green road rating system. The application of the technique allowed the developers to identify the main aspects, categories, and parameters of the evaluation system (indicators and credits) and to assign appropriate weightings to each. This study used a mathematical decision-making technique called the analytic hierarchy process (AHP). The developed system includes six categories, which are Green Road Design/Pavement Technology, Green Environment, Green Resources and Energy, Green Traffic System Highway, Green Traffic System National Highway, and Costume Credits.

The development of Malaysia’s Green Highway Index was studied by Zaim et al. [25]. In this study, after defining the main criteria, a group of 30 experts identified the 27 main and 58 sub-elements of the national rating system through workshops. The importance of the elements was then determined according to the responses of 239 participants in a questionnaire survey by evaluating the responses by factor analysis using the statistical software package (SPSS) developed for the social sciences. The final system in Malaysia includes five categories. These are: Design and Construction Activities, Energy Efficiency, Environmental and Water Management, Materials and Technology, and Social and Safety Activities.

The establishment of India’s sustainability rating system is described in the study of Singh and Jain [27]. After defining the objectives of the scheme, India identified 20 industry experts (10 from the government and 10 from the construction industry), who determined the categories, subcategories, and credits suitable for the promotion of sustainability. This was achieved by reviewing the existing systems (BE2ST, GreenPave, Envision, STARS, CEEQUAL, Green-guide, GreenLITES, GreenRoads, I-LAST, and INVEST). The system was developed with the support of the LEED India and the Green Rating for Integrated Habitat Assessment (GRIHA) building evaluation systems. To weigh the categories and their elements, the scoring system was determined by a questionnaire survey, where the interviewed parties rated the importance of the elements in the Indian practice on a scale of five. The developed system evaluates projects based on six main categories. These are: Selection and Planning, Energy Conservation, Water Conservation, Material and Resources, Environment Quality, and Innovation in Design. Within the categories, a total of 56 indicators and 170 credits support the evaluation.

Another method was used to establish a rating system for the US state of Georgia. A report from the Georgia Transportation Institute [28] shows that after studying the rating systems, the project team decided to select an existing one as a template and base for developing the system. The selection was made in conjunction with the project team based on the research team’s experience in road construction and information from a team of state engineers, designers, and environmental experts. The working group chose the GreenLITES system from New York, which was modified to make it applicable to the unique natural and regional characteristics of the state of Georgia.

In Latin America, the World Bank Latin American and Caribbean Region established a rating system, which is described by Montgomery et al. [29]. The guide aims to help decision-makers and technicians in the road construction industry to achieve more environmentally sustainable road projects in developing countries. It is designed to be applicable at any stage of a project. The elements of these Environmentally Sustainable Criteria are based on the following five rating systems: Envision, CEEQUAL, INVEST, Green Roads, and GreenLITES. The final tool consists of over 330 sustainability-based criteria, which are separated into four main road transport project phases: 41 for Systems Planning, 108 for Project Planning and Design, 94 for Construction, and 91 for Road Operation and Maintenance. These are available on a separate evaluation sheet. It is, obviously, not expected that a project will meet all the criteria; instead, they should be used as a list of “potentially sustainable ideas and opportunities”. The assessment should be carried out in cooperation with the involved persons, such as decision-makers, road construction engineers, environmental and social professionals, construction contractors, and operation and maintenance professionals. Furthermore, the selected sustainable activities must be cost-effective and add value to the project. Measuring performance through on-site monitoring, observation, and documentation is an important step in presenting actual results and should be designed and implemented well. The guide can be used as an input or reference for project design, construction, operation, and maintenance contracts, as well as third-party oversight contracts. The article also presents an experience of using the guide in one Argentinian and two Brazilian projects.

2.8. Conclusion of the Literature Review

The literature review points out that there are two options in setting up a national evaluation system. One way is for a country to develop its own criteria and credit system, which are defined by a larger group of experts and professionals. This approach usually uses the Analytic Hierarchy Process (AHP), Analytic Network Process (ANP), or Delphi technique through a set of questionnaires to calculate the importance (or weight) of the indicators [30]. The active participation of different professional parties in the processes, both in the working group and during the determination of the weighting, is important. Thus, this method is usually used when the evaluation system is developed on behalf of the government.

The other solution is to select a sustainability assessment system that has already been proven as effective in practice and use that as a basis. In this case, the next step is to adapt its elements to fit national specifics.

3. Materials and Methods

Firstly, this paper collected the relevant and commonly used systems, as well as some of the established national rating or certificating systems. The literature review intended to show the wide scope of application and wide variability of the existing systems and the method of formation and installation of different national practices relating to rating systems. It should be noted that the examined systems differ in terms of the range of applicable projects that can be evaluated, the stages of evaluation (planning, design, construction, and maintenance), and the system of criteria.

The aim of the research presented in this paper is to examine the applicability of sustainability rating systems in Hungary and select the most suitable system. The compared systems were previously analyzed in a study conducted by the Hungarian Road Administration earlier. The scope of that study was to review the international practices related to green rating systems and to analyze the existing and proved tools and methods for the clarification and establishment of the preconditions of a domestic model. In this paper, the selection of the most suitable system using Multi-Criteria Decision Making (MCDM) analysis has been made. Based on the literature review, the Analytical Hierarchy Process (AHP) method was found to be the most commonly used method for numerous construction-related decisions, as well as in the case of the determination of the weights of different indicators or criteria for sustainability ratings [4,19,30,31,32,33,34,35,36,37]. Next to AHP, studies also commonly used the Delphi model, Simple Additive Weighting (SAW), the TOPSIS method or other MCDM techniques, and combinations of them for decision-making or ranking [38,39,40,41,42,43]. This paper uses the TOPSIS method, since the focus of this paper is to rank the already existing rating systems instead of weighing the indicators of a new national evaluation tool.

TOPSIS is a well-known technique for dealing with the ranking problem of alternatives so that the preferred option should be closest to the positive ideal solution and, at the same time, furthest from the perfect negative solution. A more detailed description of the method can be found in Section 4.2. The first step of the calculation is to define the criteria and their weights. The criteria were mainly taken from the result of an already mentioned Hungarian study [5]. The expansion of the criteria and the input data (weights) of the TOPSIS method were determined by a small research group of industry experts and academic professionals based on Hungarian practices and methodology. The research group consisted of experts from the National Infrastructure Development Corporation representing the asset owner side and experts from one of the largest infrastructure design and consulting company (Unitef ‘83 Zrt.), representing the designer side. The eleven members of the group collected a wide range of experience (5–32 years) throughout their career with conducting and approving environmental studies, innovation, and assessing sustainable technologies. Some of the members also have academic background. After the selection, the aim of the research was to examine the application of the most suitable system through a Hungarian transportation system project. With this, the authors intend to examine the elements of the selected system in order to determine the strengths and weaknesses of the Hungarian practice and filter out the elements that cannot be applied in the local practice.

4. Analysis and Interpretation

4.1. Comparison of Green Rating Systems and the Selection of the Most Suitable System Using the TOPSIS Method

Several rating and evaluation systems are currently available and used around the globe. The systems examined in this study were selected by the previously (in Section 3) mentioned study, which was conducted by the Hungarian Road Administration in 2015 by a small research team of experts with an academic or industry background. The summary of the Greenroads, GreenLITES, I-LAST, Envision, and INVEST systems are presented in

Table 1. Summary on the examined rating systems.

Name	Greenroads	GreenLITES	I-LAST	Envision	INVEST
Full Name	Green roads	Green Leadership In Transportation Environmental Sustainability	Illinois- Livable and Sustainable Transportation	Envision	Infrastructure Voluntary Evaluation Sustainability Tool
Origin	University of Washington Washington	Department of Transportation New York	Department of Transportation Illinois	Institute for Sustainable Infrastructure Washington	Federal Highway Administration Washington
Year of establishment	2007	2008	2010	2012	2010
Website	www.greenroads.org	www.dot.ny.gov/programs/greenlites	www.idot.illinois.gov	datahttp://sustainableinfrastructure.org/envision/	http://www.sustainablehighways.org/
Certification	Bronze/Silver/Gold/Evergreen	Certified/Silver/Gold/Evergreen	-	Verified/Silver/Gold/Platinum	-
Last Version	42970	2010 April (2012 February)	41179	43207	2018
Project level	Project development	Project design, Operation	Project development	Planning, Project development, Operation and maintenance	System planning, Project development, Operation and maintenance
Duration of validation	90 day	120 day	-	90 day	90 day
Number of criteria	61	175	153	64	11/27/34/29/27/11+(/op)
Maximum points	130	278	233	1000	63/136/171/119/153/136(/210)
Minimum point	30%	5%	-	20%	-

[44].

In general, each system examined the rates of projects at different levels of projects, i.e., planning, project development, operation, and maintenance (Figure 2). To achieve this, checklists with different categories, different weights, and maximum points are used.

Most of the system credits fall into the following categories:

• Material and pavement technology.
• Environment and water.
• Design and construction.
• Accessibility and equality.
• Energy efficiency.

However, different systems consider different areas as the “most important” (Figure 3), i.e., they emphasize (weight) the importance of environmental solutions in the main categories in different ways.

The number of credits listed and the maximum points available also vary significantly, but all certification systems have a minimum score that is required for certification (5–30%). The results of the project can be used for educational, labelling, and various marketing purposes and can aid in decision-making [45] (Greenroads, 2017) (GreenLITES, 2017) (I-LAST, 2012) (Envision, 2018) (INVEST, 2018).

Some of the abovementioned categories have greater importance in relation to the current Hungarian situation than the others. For instance, the protection of water quality and the ecosystem as well as having a proper pavement design system are very important and should be considered as significant features. Innovative design ideas and construction methods are, on the other hand, used only occasionally, usually in pilot projects. Energy efficiency during the lifecycle of the projects is not examined during most of the projects [5]. The study considers these aspects of sustainability criteria to be extremely important; therefore, they will form part of the evaluation in the comparison of the rating systems.

4.2. Description of the TOPSIS Method

The “Technique for Order Preference by Similarity to the Ideal Solution” (TOPSIS) method, developed by Hwang and Yoon [46], is suitable for solving multi-objective decision-making (MODM) problems. Hwang explained that the multi-criteria decision analysis problem can be considered as a geometric system. The m alternative evaluated by the n attribute is like the m point of the n-dimensional space, so the most advantageous alternative should be the point that is located closest to the ideal solution and furthest from the worst solution. The idea of the method is, therefore, to have the most advantageous alternative, which is as close as possible to the “high-level solution” and as far as possible from the “low-level solution” from a geometric point of view (Euclidean). The advantage of this is that this method results in a simple and indisputable order of preference.

In the publication of Lai, Liu, and Hwang [47], the application of TOPSIS by multi-criteria decision-making problems was presented. According to this, for many of these problems, the decision-maker wants to achieve more than one goal when choosing a course of action, while meeting the constraints required by the environment, processes, and resources. From a mathematical point of view, these problems can be represented as:

max [f_1 (x),f_2 (x),…,f_k (x)]

(1)

s.t. x∈X = {x | g_i (x) ≤ 0, I = 1,2,…,m}

(2)

where x is the n-dimensional decision variable vector. The problem consists of n decision variables, m constants, and k objectives. Any of the functions can be nonlinear. In the literature, this problem is often a vector maximization problem. In general, MODM techniques can be divided into four classes: (a) preferential information, which is not articulated; (b) a prior articulation of preference information; (c) a progressive articulation of preference information or interactive methods; (d) a subsequent articulation of preferred information or non-dominant solution generation methods. In the case of TOPSIS, preferential information is not articulated.

The principle of the method is, therefore, that the chosen alternative should be as close as possible to the positive ideal solution (PIS) and the furthest from the negative ideal solution (NIS). A single criterion that has the shortest distance from a given goal or PIS is not enough to satisfy decision-makers. In practice, an ideal decision is preferred that not only provides as much benefit as possible but also avoids as much risk as possible.

Based on the summary of D. L. Olson [48], TOPSIS determines the ideal attribute through a series of steps:

(1)

Determination of performance data for n alternatives over k criteria. (Raw measurements (xij) are usually converted to standardized measurements (sij)).

(2)

Development of the set of importance weights for each criterion.

(3)

Determining an ideal alternative, s+.

(4)

Defining a negative maximum (low point) alternative, s-.

(5)

Determining the distance measurement over each criterion to both the ideal (D+) and negative maximum (D-).

(6)

For each alternative, determining the ratio R by:

R = D⁻/(D⁻ + D⁺)

(3)

where R equals the distance to the negative ideal solution, divided by the sum of the distances to the ideal and nadir solution.

(7)

Ranking alternatives by maximizing the ratio in Equation (3).

With this series of steps, TOPSIS minimizes the distance to the ideal solution while maximizing the distance from the negative ideal solution. For steps (2) to (5), several different methods can be used.

4.3. Determination of the Most Suitable Rating System Using the TOPSIS Method

As a result of the evaluation, we want to determine which of the evaluation systems of Greenroads, GreenLITES, I-LAST, Envision, and INVEST is the one that satisfies the criteria to the greatest extent and should be chosen; therefore, it can potentially be used in Hungarian road construction practice. The first step to achieve this is to define the set of criteria which is used to examine and distinguish between the systems. This study identifies 12 different criteria for the evaluation. Seven of the criteria (K1–K6 and K12) were taken over from the previously mentioned Hungarian research [5]. This paper, after interviews with experts, expanded the criteria with K7–K11 based on their importance in Hungarian practice. Further revision of these categories was beyond the scope of this paper.

The examined criteria are:

• K1—Accessibility.
• K2—Clarity and comprehensibility.
• K3—Scope of applicability at different stages of projects.
• K4—Availability of required data.
• K5—Availability of required documentation.
• K6—Internationally applicable experiences.
• K7—Training and development.
• K8—Importance of energy efficiency.
• K9—Importance of environmental awareness in relation to the material and track structure.
• K10—Importance of environmental awareness in relation to water and the ecosystem.
• K11—Importance of accessibility and equality in the project development.
• K12—Promotion of innovation.

The results of the obtained performance data are summarized in

Table 2. Classification of the rating systems for the Technique for Order Preference by Similarity to the Ideal Solution (TOPSIS) analysis.

Rating System	Criterion
	K1	K2	K3	K4	K5	K6	K7	K8	K9	K10	K11	K12
Greenroads	5	5	3	4	4	5	5	5	4	4	4	3
GreenLITES	3	4	2	3	3	2	2	5	5	3	2	3
I-Last	4	5	3	3	3	1	2	3	3	5	4	2
Envision	5	5	4	4	4	5	5	4	3	4	3	5
Invest	4	4	5	3	3	3	3	3	2	2	5	3

. This is a normalized classification of the rating systems, where the classification is conducted according to a 1 to 5 scale. A result of 1 is the least favorable, and a result of 5 is the most favorable result for the criteria. The determination of the weights in the research is based on the results of personal interviews of industry and academic experts, in addition to the personal experience and technical estimation of the authors. It also draws from the comprehensive publications of Andrew S. Chang and Calista Y. Ts. [49,50]. Details on the scoring can be found in Appendix B.

The next task was to calculate the weighted normalized classification based on the following Equation (4):

$$d_{ij}=\frac{x_{ij}}{\sqrt{{{\displaystyle \sum }}_{i=1}^5{x}_{ij}{}^2}}$$

(4)

Table 3. Weighted normalized classification results.

Rating System	Criterion
	K1	K2	K3	K4	K5	K6	K7	K8	K9	K10	K11	K12
Greenroads	0.524	0.483	0.378	0.521	0.521	0.625	0.611	0.546	0.504	0.478	0.478	0.401
GreenLITES	0.314	0.387	0.252	0.391	0.391	0.250	0.244	0.546	0.630	0.359	0.239	0.401
I-Last	0.419	0.483	0.378	0.391	0.391	0.125	0.244	0.327	0.378	0.598	0.478	0.267
Envision	0.524	0.483	0.504	0.521	0.521	0.625	0.611	0.436	0.378	0.478	0.359	0.668
Invest	0.419	0.387	0.630	0.391	0.391	0.375	0.367	0.327	0.252	0.239	0.598	0.401
SUM

shows the results.

Based on the above, the positive and negative ideal solutions can be identified using Equations (5) and (6). The results and are shown in

Table 4. Weighted normalized classification results.

Ideal Solutions	Criterion
	K1	K2	K3	K4	K5	K6	K7	K8	K9	K10	K11	K12
Positiv ideal solution A+	0.524	0.483	0.630	0.521	0.521	0.625	0.611	0.546	0.630	0.598	0.598	0.668
Negativ ideal solution A-	0.314	0.387	0.252	0.391	0.391	0.125	0.244	0.327	0.252	0.239	0.239	0.267

.

$$A^{*}=\left\{ma{x}_j{d}_{ij}|j\in J_1,mi{n}_j,d_{ij}\left|j\in J_2\right|i=1,\dots , 5\right\}$$

(5)

$$A^{-}=\left\{mi{n}_j{d}_{ij}|j\in J_1,ma{x}_j,d_{ij}\left|j\in J_2\right|i=1,\dots , 5\right\}$$

(6)

The next step was to identify the distances. The distance is calculated using the n-dimensional Euclidean distance for both positive (Di*) and negative (Di⁻) distances Equations (7) and (8). The results are presented in

Table 5. Distances from the positive and negative ideal solutions.

D *	Criterion												SUM
	K1	K2	K3	K4	K5	K6	K7	K8	K9	K10	K11	K12
Greenroads	0.000	0.000	0.063	0.000	0.000	0.000	0.000	0.000	0.016	0.014	0.014	0.071	0.179
GreenLITES	0.044	0.009	0.143	0.017	0.017	0.141	0.134	0.000	0.000	0.057	0.129	0.071	0.762
I-Last	0.011	0.000	0.063	0.017	0.017	0.250	0.134	0.048	0.063	0.000	0.014	0.161	0.779
Envision	0.000	0.000	0.016	0.000	0.000	0.000	0.000	0.012	0.063	0.014	0.057	0.000	0.163
Invest	0.011	0.009	0.000	0.017	0.017	0.063	0.060	0.048	0.143	0.129	0.000	0.071	0.567
D−	Criterion												SUM
	K1	K2	K3	K4	K5	K6	K7	K8	K9	K10	K11	K12
Greenroads	0.044	0.009	0.016	0.017	0.017	0.250	0.134	0.048	0.063	0.057	0.057	0.018	0.731
GreenLITES	0.000	0.000	0.000	0.000	0.000	0.016	0.000	0.048	0.143	0.014	0.000	0.018	0.238
I-Last	0.011	0.009	0.016	0.000	0.000	0.000	0.000	0.000	0.016	0.129	0.057	0.000	0.238
Envision	0.044	0.009	0.063	0.017	0.017	0.250	0.134	0.012	0.016	0.057	0.014	0.161	0.795
Invest	0.011	0.000	0.143	0.000	0.000	0.063	0.015	0.000	0.000	0.000	0.129	0.018	0.378

.

$$D_i^{*}=\sqrt{{\displaystyle \sum }_{j=1}^{12}{(d_{ij}-d_j^{*})}^2}$$

(7)

$$D_i^{-}=\sqrt{{\displaystyle \sum }_{j=1}^{12}{(d_{ij}-d_j^{-})}^2}$$

(8)

Following calculating the distances, the next step was to determine the R relative proximity ratio. This is calculated using Equation (9).

$$R_i= \frac{D_i^{*}}{D_i^{*}- D_i^{-}}$$

(9)

The results should have a value between 0–1. The solution whose value is closest to 0 has the highest priority. The result of the calculation is shown in

Table 6. Determination of relative proximity.

Rating System	D+	D−	Ri
Greenroads	0.179	0.731	0.197
GreenLITES	0.762	0.238	0.762
I-Last	0.779	0.238	0.766
Envision	0.163	0.795	0.170
Invest	0.567	0.378	0.600

below.

Table 6 shows that, based on the 12 criteria listed above and examined in the present study, the Envision rating system satisfies the most criteria. It is closely followed by Greenroads. The next in ranking were INVEST, GreenLITES, and I-LAST. In the future, the research should focus on the application of the Envision rating system of Hungarian road infrastructure projects.

5. Conclusions

To enhance sustainability in the construction industry, different rating and certificating systems have been developed. These usually list a set of sustainability practices in different categories, such as material, pavement, environment, water, energy, and accessibility, and can evaluate the sustainability level of projects during their stages, i.e., planning, design, construction, and maintenance. The systems aim to motivate decision-makers, construction companies, and other stakeholders to make the use of these practices and methods common at a higher level. While most of the techniques and practices are available in Hungary, the use of them varies. The concerns of a lower level of performance when using alternative technologies, such as warm mix asphalt (WMA) or recycled asphalt pavement (RAP), and the extra costs and time required for sustainable designs resulted in a low demand for such techniques and practices. Therefore, well-structured regulation is needed to promote these techniques and develop appropriate mindsets. Different “green” objective rating systems can help increase the level of sustainability in terms of both design and implementation.

The present paper reviewed some of the commonly used rating systems and the method of some of the nationally established sustainable indicator tools and systems. The literature highlights that there are two options for setting up a national evaluation system. One way is for a country to develop its own criteria and credit system using experts’ input. The scoring (weighting) in this approach is usually obtained through a questionnaire survey of a larger group of professionals, and the Analytic Hierarchy Process (AHP), Analytic Network Process (ANP), or Delphi technique are typically used to calculate the importance (or weight) of the indicators. The other way is to select a sustainability assessment system that has already been proven in practice and use that as a basis. In this case, the next step would be to adopt these elements to fit national specifics.

Following the literature review, this paper compared five previously determined and widely used rating systems, with the aim of choosing the one which best fits the Hungarian specifics and therefore providing a base for a Hungarian national rating system. The compared systems were the Greenroads, GreenLITES, I-LAST, Envision, and INVEST rating systems. The comparison was conducted using the TOPSIS multi-objective decision-making method. With this approach, the multi-criteria decision analysis problem can be considered as a geometric system. The m alternative evaluated by the n attribute is similar to the m point of the n-dimensional space, so the most advantageous alternative should be the point located closest to the ideal solution and furthest from the worst solution. The systems were evaluated against 12 criteria determined in a previous study. The input weights were determined by a small group of experts representing the asset owner and designer side. With these input data, the calculation was conducted, and as a result, the Envision system was shown to be the most suitable rating system for Hungary. This was closely followed by the Greenroads system. The utilization of the multi-objective decision-making method by the use of TOPSIS provided a comprehensive and objective method for selecting the most suitable green rating system for the Hungarian road infrastructure projects.

In the future, research should focus on the application of the Envision rating system in Hungarian road design, applying it in road construction projects, with the aim of examining the elements of the selected system, determining the strengths and weaknesses of the Hungarian practices, and filtering out the elements that cannot be applied in local systems.

Further work needs to be completed in terms of expanding the expert group for the input weights, including representatives and experts from other organizations, such as construction companies, material manufacturers, organizations developing and running recycling technologies, and financial and ministerial organizations. Input from these organizations and individuals may change the weighting; however, the methodology presented in this paper could be readily re-applied. If new green rating systems would be available over time, this methodology could be used for an updated ranking to find the best green rating system for Hungarian conditions.