A Critical Perspective and Inclusive Analysis of Sustainable Road Infrastructure Literature

Citation: Alhjouj, A.; Bonoli, A.; Zamorano, M. A Critical Perspective and Inclusive Analysis of Sustainable Road Infrastructure Literature. Appl. Sci. 2022,12, 12996. https://doi.org/ 10.3390/app122412996 Academic Editor: Antonella Petrillo Received: 16 November 2022 Accepted: 15 December 2022 Published: 18 December 2022 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). applied sciences Review A Critical Perspective and Inclusive Analysis of Sustainable Road Infrastructure Literature Ahmad Alhjouj 1, Alessandra Bonoli 2and Montserrat Zamorano 1,* 1Department of Civil Engineering, University of Granada, 18071 Granada, Spain 2Department of Civil, Chemical, Environmental, and Materials Engineering, University of Bologna, 40126 Bologna, Italy *Correspondence: [email protected] Abstract: In response to the important environmental impacts produced by the road transport network during all its life cycle stages, a set of measurements to include sustainable principles have been identified between 1997–2021, analysed and mapped by applying SciMAT and VOSviewer. The results have shown the predominance of issues which analyse the life cycle assessment of road infrastructures in its both environmental and economic dimension as a way to mitigate their effects on climate change, including the reduction of resources and energy consumption, or of energy consumption and greenhouse gases emissions during the construction and operation stages, respectively. However, the incorporation of the social life cycle assessment dimension, their adaptation to climate change, and the use of smart roads are still in an early stage. Therefore, efforts to include these issues are necessary to address their design according to the resilience concept and ensuring a cleaner and more competitive and climate-neutral Europe. Keywords: sustainable road; sustainable highway; green road; green highway; rating systems; sustainability 1. Introduction Road transport shows important advantages in comparison to other modes of transport, for example accessibility, adaptability to individual needs [ 1 ], the promotion of robust and sustainable regions [ 2 ]. Road transport also delivers economic benefits [ 3 ]. In consequence, a huge global road infrastructure network is operating nowadays, and it is expected to increase by 2050 [ 4 ], resulting in the main used transport mode in European countries [ 5 ] which includes strategic infrastructures in the economic [ 6 , 7 ] and social [ 6 ] development of countries. Road infrastructure integrates all road categories as the main element [ 8 ], as well as a set of facilities, structures, signage and markings, and electrical systems, to guarantee safe and efficient traffic [ 9 ]. This infrastructure has significant environmental impacts during all its life cycle stages, i.e., construction, operation, and maintenance, including: consumption of natural resources (raw materials and energy), airborne emissions, acoustic pollution, ground and surface water contamination, habitat disturbance, land use or negative effects on plants [ 10 ], lighting disturbances [ 11 ], wildlife or animal movement [ 12 ], soil acidification produced by nitrogen oxide emissions, or chemical effects of road dust [ 11 ], among others. Besides, worldwide, the transport sector produces 32% of greenhouse gas (GHG) emissions, of which 75% are related to road transport [ 13 ], of which the largest portion is produced during the road operation phase due to vehicle exhaust fumes [ 14 ]. Besides, large quantities of natural resources are consumed during road construction and maintenance; in fact, roads consume about 60% of natural resources [ 15 ]. On the other hand, large amounts of waste are produced in road construction, leading to a significant negative environmental impacts and climate change effects [ 16 ]. In consequence, the construction, operation, and maintenance of roads have clear effects on climate change [ 16 ]; besides, road transport has Appl. Sci. 2022,12, 12996. https://doi.org/10.3390/app122412996 https://www.mdpi.com/journal/applsci Appl. Sci. 2022,12, 12996 2 of 25 also negative effects from a social point of view, for example because of the high mortality rate associated with traffic accidents worldwide [17]. To solve the problems described above, and according to the sustainability concept reported by Bruntland in 1987, environmental impact, social equity, and economic efficiency are dimensions that have to be prioritised by governments [ 18 ] for sustainable road development throughout all the stages of its life (planning, construction, maintenance, and disposal) [ 19 ], as a way to ensure economic growth and social development, as well as environmental safety [ 20 ]. As a result, the implementation of sustainability in road infrastructure has become dependent on providing measurements and guidance for including sustainable principles in road projects [ 21 ], resulting in a dozen voluntary certification and rating systems to evaluate the level of sustainability of road design, construction, and maintenance. These systems give a set of guidelines to achieve more sustainable road transportation to road transport infrastructure designers and managers [ 22 ]. Despite all of this, and taking into account the need both to implement measures to mitigate climate change and also to adapt to it, nowadays, it is necessary to implement new key milestones included in different agreements or planning in the concept of sustainable road infrastructure in Europe. This is the case of the 2030 Agenda for Sustainable Development, the European Circular Economy plan, and the European Green Deal. The 17 Sustainable Development Goals (SDGs), which are part of the 2030 Agenda for Sustainable Development, include a total of 169 targets aimed at people, planet, prosperity, peace, and partnership [ 23 ]. In this framework, road transport can help deliver on some of the targets of the SDGs, including: SDG2 (zero hunger), on the basis of the key role of road transport in making sure that workers, equipment, products, and food get efficiently and quickly to people; SDG9 (industry, innovation and infrastructure), because of the importance of infrastructure in the connectivity between economies for trade in goods and services, and between the people who trade; SDG11 (sustainable cities and communities), in relation to the prominence of road infrastructure in mobility and logistics networks in cities; SDG13 (climate action) because of the importance of road transport in the decarbonization of the sector, from the energy source to the energy use, including the uses of resources in the construction and maintenance stages; and finally, SDG17 (partnerships and collaboration), in relation to the crucial and necessary public–private collaboration. On the other hand, the first European Circular Economy Action Plan, Closing the loop, in 2015, as well as the New Circular Economy Action Plan, For a cleaner and more competitive Europe, adopted by the European Commission in 2020, aim at the implementation of the 3 Rs principles (Reduce, Reuse, Recycling). These principles also influence infrastructure design [ 24 ], providing the idea of sustainability and green construction, and reducing environmental damage through the recycling and reuse of waste and reduced use of resources, materials, and energy [ 8 ], as well as finding ways to reduce the emission of greenhouse gases and other emissions released from fossil fuels [ 25 ]. Finally, the European Green Deal adopted a set of proposals for reducing net greenhouse gas emissions by at least 55% (compared to 1990 levels) by 2030. The European Green Deal emphasised important targets that are necessary in the transport sector in order to achieve a 90% reduction of greenhouse gas emission by 2050 [26]. As a result, the need to fulfil the cited new key milestones in terms of sustainability, as well as the severe effects of the increasing temperature, precipitation and storm events, and rising sea levels on road infrastructure, as a consequence of climate change [ 27 – 31 ], make it necessary to evolve towards the concept of resilience, which is defined as “the ability to resist, absorb, accommodate to and recover from the effects of a hazard in a timely and efficient manner” [ 32 ]; in fact, the ability of roads to be adapted to climate change is understood not only as part of mitigation, but also resilience. On the other hand, nowadays the concept of smart roads, referred to those that improve user, vehicle, and infrastructure connections, is achieving an important role for more efficient, safe, and sustainable roads; definitely when on the subject on resilient roads [33]. According to the above, it is possible to assert that road infrastructure sustainability is a broad research field involving a huge diversity of approaches and disciplines. In addition, Appl. Sci. 2022,12, 12996 3 of 25 the pace of research in the field of sustainability is rapid, outstripping the capacity to cover all the aspects related with it in a single review [ 34 ]. Therefore, a critical perspective and inclusive analysis of the literature is needed to facilitate global knowledge acquisition in this research field. To do that, bibliometrics, a concept presented by Alan Pitchard in 1969 and boosted by the advent of the Internet during the last decades, could provide both with objective criteria for evaluating the research in this field [ 35 ]. Some bibliometric analyses related with sustainable roads have been published; these include a study on self-healing asphalt as a way to improve road sustainability [ 18 ], or another to determine the extent of the previous research that has been carried out on the consumption of energy in all stages of road construction projects to improve sustainable and green roads [ 36 ]. However, bibliometric analysis studies defining the state-of-the-art of the concept of sustainability applied to road infrastructure in its global dimensions have not been reported. Such an analysis could be considered a good way to identify not only the evolution of the research field of sustainable roads, but also how new subjects that which are clearly related with sustainability concepts, such as resilience, adaptation to climate change and smart roads, will be incorporated in the future. In consequence, the main objective of this study has been to perform a bibliography analysis and systematic literature review (SLR) of sustainable road infrastructure using a science mapping approach to gain a one-stop overview and to identify knowledge gaps [ 37 ]. This work aims to identify the evolution of current and future trends in road infrastructure sustainability research field. Results can be used as a guideline for the development of future planning strategies, as well as research in low carbon climate-responsive road infrastructure adapted to climate change and supported by new technological advances. 2. Materials and Methods This paper collects and synthesises the available research on sustainable road transport infrastructure to produce a quantitative evaluation and literature review. To develop this study, the applied methodology includes three different phases and sub-phases summarised in Figure 1and described below. Appl. Sci. 2022, 12, x FOR PEER REVIEW 4 of 28 Figure 1. Applied methodology description. 2.1. Phase I. Selection of Documents for the Analysis and Determination of Time Horizon The combination of words identified as key in the field of sustainable roads has been applied to define the search strings in the scientific bibliography database, using the Scopus database because of its broader bibliometric scope and most current data [38,39]. Following PRISMA flowchart guidelines, the primary resulting search has been filtered for title and abstract to remove unwanted papers in order to result in the final set of relevant documents included in this study for analysis. Finally, the time horizon of this research has been determined according to the year of publication of the first paper in the field, and it will extend until 2021, since the document search was carried out in March 2022. 2.2. Phase II. Scientometric Analysis The final set of relevant documents selected for this study were exported from the Scopus database both as Comma Separated Values (CSV) and Research Information System (RIS) files to be dealt with using the open software tools VOSviewer (version 1.6.18) and SciMAT (version 1.1.04), respectively, with the objective of performing their bibliometric analysis. The most relevant publication sources, authors, countries, documents and keywords in the research field were assessed during the analysis and networks and illustrated by creating maps and graphs, and displaying their statistical values according to the following sequence for scientometric analysis: • Yearly publication trend. The analysis of the number of publications is important to know the developments and patterns in the research. In consequence, the time horizon has been analysed in terms of the total and cumulative number of papers published, but it has also been categorised into different sub-periods for a more detailed knowledge of the publication trend. • Science mapping. VOSviewer has been applied to determine qualitatively and quantitatively measures such as the number of published documents and number of citations to produce scientific maps which represent the most relevant publication sources, countries, authors, and documents. Figure 1. Applied methodology description. Appl. Sci. 2022,12, 12996 4 of 25 2.1. Phase I. Selection of Documents for the Analysis and Determination of Time Horizon The combination of words identified as key in the field of sustainable roads has been applied to define the search strings in the scientific bibliography database, using the Scopus database because of its broader bibliometric scope and most current data [ 38 , 39 ]. Following PRISMA flowchart guidelines, the primary resulting search has been filtered for title and abstract to remove unwanted papers in order to result in the final set of relevant documents included in this study for analysis. Finally, the time horizon of this research has been determined according to the year of publication of the first paper in the field, and it will extend until 2021, since the document search was carried out in March 2022. 2.2. Phase II. Scientometric Analysis The final set of relevant documents selected for this study were exported from the Scopus database both as Comma Separated Values (CSV) and Research Information System (RIS) files to be dealt with using the open software tools VOSviewer (version 1.6.18) and SciMAT (version 1.1.04), respectively, with the objective of performing their bibliometric analysis. The most relevant publication sources, authors, countries, documents and keywords in the research field were assessed during the analysis and networks and illustrated by creating maps and graphs, and displaying their statistical values according to the following sequence for scientometric analysis: • Yearly publication trend. The analysis of the number of publications is important to know the developments and patterns in the research. In consequence, the time horizon has been analysed in terms of the total and cumulative number of papers published, but it has also been categorised into different sub-periods for a more detailed knowledge of the publication trend. • Science mapping. VOSviewer has been applied to determine qualitatively and quantitatively measures such as the number of published documents and number of citations to produce scientific maps which represent the most relevant publication sources, countries, authors, and documents. • Key themes analysis. Keywords of a document identify the most relevant concepts considered and discussed; they are the core content of the document, so their analysis is essential. VOSviewer has been applied for keywords co-occurrence analysis which relates and connects papers keywords, whereas SciMAT has been used to study the evolution of research themes with an overlay graph, evolution maps, and strategy diagrams. 2.3. Phase III. A Review of Sustainable Roadways Finally, the most relevant themes and challenges of sustainability in road infrastructure identified in the bibliometric analysis have been briefly analysed to give experts in the field a comprehensive view of the current situation and guide about the prospect of future research in the field. 3. Results The results of the bibliometric analysis, as well as their discussion and the literature review, have been developed according to the defined sequence. The most relevant results are summarised below. 3.1. Selection of Documents for the Analysis and Determination of Horizon Time With the objective of refining the search, this review has defined the following search string in the title, abstract and keywords, in the Scopus database: “sustainable road” OR “sustainable highway” OR “sustainability of road” OR “sustainability of the road” OR “sustainable roadway” OR “green road” OR “green highway” OR “green roadway” OR “sustainable pavement” OR “green pavement”. The primary search resulted in 936 documents which were filtered according to the PRISMA flowchart (Figure 2) to include only articles and conference proceedings written in the English language, and to exclude docu- Appl. Sci. 2022,12, 12996 5 of 25 ments published in 2022, as well as documents which did not fall within the scope of the review. This screening resulted in a final set of 683 documents which were exported as both CSV and RIS files. As the first articles were found in the year 1997 (Figure 3a), the time horizon of this study was established from that year to 2021. Appl. Sci. 2022, 12, x FOR PEER REVIEW 5 of 28 • Key themes analysis. Keywords of a document identify the most relevant concepts considered and discussed; they are the core content of the document, so their analysis is essential. VOSviewer has been applied for keywords co-occurrence analysis which relates and connects papers keywords, whereas SciMAT has been used to study the evolution of research themes with an overlay graph, evolution maps, and strategy diagrams. 2.3. Phase III. A Review of Sustainable Roadways Finally, the most relevant themes and challenges of sustainability in road infrastructure identified in the bibliometric analysis have been briefly analysed to give experts in the field a comprehensive view of the current situation and guide about the prospect of future research in the field. 3. Results The results of the bibliometric analysis, as well as their discussion and the literature review, have been developed according to the defined sequence. The most relevant results are summarised below. 3.1. Selection of Documents for the Analysis and Determination of Horizon Time With the objective of refining the search, this review has defined the following search string in the title, abstract and keywords, in the Scopus database: “sustainable road” OR “sustainable highway” OR “sustainability of road” OR “sustainability of the road” OR “sustainable roadway” OR “green road” OR “green highway” OR “green roadway” OR “sustainable pavement” OR “green pavement”. The primary search resulted in 936 documents which were filtered according to the PRISMA flowchart (Figure 2) to include only articles and conference proceedings written in the English language, and to exclude documents published in 2022, as well as documents which did not fall within the scope of the review. This screening resulted in a final set of 683 documents which were exported as both CSV and RIS files. As the first articles were found in the year 1997 (Figure 3a), the time horizon of this study was established from that year to 2021. Figure 2. Results of the application of PRISMA flowchart. Figure 2. Results of the application of PRISMA flowchart. Appl. Sci. 2022, 12, x FOR PEER REVIEW 6 of 28 (a) (b) Figure 3. Number of documents published in the time horizon (1997‒2021) and subperiod: (a) document per year and (b) accumulated number of documents. 3.2. Scientometric Analysis The scientometric analysis was developed according to the defined sequence, including yearly publication trends, science mapping, and key themes analysis. The results in terms of the qualitative and quantitative contribution to the research field are analysed and discussed below. 3.2.1. Yearly Publications Trend Figure 3 summarises the documents published per year (Figure 3a) and the accumulated number of documents (Figure 3b), showing the increase in the number of documents along the time horizon, related to the growing interest by researchers in exploring the Figure 3. Number of documents published in the time horizon (1997–2021) and subperiod: ( a ) document per year and (b) accumulated number of documents. Appl. Sci. 2022,12, 12996 6 of 25 3.2. Scientometric Analysis The scientometric analysis was developed according to the defined sequence, including yearly publication trends, science mapping, and key themes analysis. The results in terms of the qualitative and quantitative contribution to the research field are analysed and discussed below. 3.2.1. Yearly Publications Trend Figure 3summarises the documents published per year (Figure 3a) and the accumulated number of documents (Figure 3b), showing the increase in the number of documents along the time horizon, related to the growing interest by researchers in exploring the sustainability of roads. For better compression of the yearly publication trend, the time horizon has been subdivided into the following three sub-periods, depending on the inflection points in the evolution of roadway sustainability and the number of documents (Figure 3b): • First sub-period (1997–2010). Latent period. This is the longest period but includes only 83 documents, so it could be considered that work was being conducted in the research field in the first steps of the sustainability concept, but was not yet developed or manifested. • Second sub-period (2011–2015). Initial development period. With a significant increase in the number of articles compared with the previous sub-period, specifically 145 documents published in 5 years, this is considered an initial development period. This increase can be explained by the increased concern for the environment, as revealed in the long traction of sustainable rating systems for roadways gained in 2010 after the application of Leadership in Energy and Environmental Design (LEED) in the case of building. This resulted in tools such as Environmentally and Economically Sustainable Transportation Infrastructure–Highways (BE2ST-in-Highways) or Green Leadership in Transportation and Environmental Sustainability (GreenLITES) [ 22 ]. The end of this period was established as 2015, corresponding to the approval of the 2030 Agenda, as well as the first European Circular Economy Action Plan. • Third sub-period (2016–2021). Consolidation period. With 455 published documents, this is the one with the highest number of documents and it corresponds to the consolidation of the development step in the research field after the approval of the circular economy plan in Europe, as well as the 2030 Agenda for sustainable development, and, in consequence, an increase of measures to stimulate its growth. This consolidation of the development in the research field is reflected in the increase of the number of sustainable rating systems developed for roadways, for example GreenPave and GreenRoads, in 2017, Invest and Envision in 2018, and The Civil Engineering Environmental Quality Assessment & Award (CEEQUAL) in 2019 [22]. 3.2.2. Science Mapping The final set of relevant documents selected for this study were analysed with the software tool VOSviewer to identify the most relevant publication sources, authors, countries, and documents in the research field to be assessed. The results are summarised in Tables 1–5and Figures 4and 5, and analysed and discussed below. In the case of sources of publication, journal rankings with the highest number of documents published, citations, average normalised citation scores, average publication year and impact factor in the last 5 years were identified. Of these, a total of 11 sources among the three rankings (Table 1), which could be considered the most influential in the research field, especially those which are included in more than one ranking: Construction and Building Materials and Journal of Cleaner Production in the publication count and total citations ranking, and European Journal of Operational Research and International Journal of Coal Geology in the total citations and average normalised citations ranking, all of them with high values of impact factor in the last 5 years. The wide spectrum of source categories observed in Table 2, with a total of 11 and the predominance of MATERIALS Appl. Sci. 2022,12, 12996 7 of 25 SCIENCE MULTIDISCIPLINARY, emphasises the different aspects of sustainability in roads [ 40 ], including those related with construction and maintenance (CONSTRUCTION AND BUILDING TECHNOLOGY, ENGINEERING CIVIL, MATERIAL SCIENCE MULTIDISCIPLINARY), operation (OPERATION AND MANAGEMENT SCIENCE, TRANSPORTATION SCIENCE AND TECHNOLOGY) as well as the environmental dimension (BIODIVERSITY, ECOLOGY, ENGINEERING ENVIRONMENTAL, ENVIRONMENTAL SCIENCE, GREEN AND SUSTAINABLE SCIENCE AND TECHNOLOGY) or their relation with cities (URBAN STUDIES). Table 1. Main sources of publication in terms of publication count, total citations and average normalised citations, and source quality. Source N◦ Documents Total Citations Average Normalised Citations Average Publication Year Impact Factor Last 5 Years Ranking Position Publication Counts Total Citations Average Normalised Citations Advanced Functional Materials 1 323 15.109 2013 11.21 - - 3 Cities 1 136 10.390 2017 6.788 - - 4 Construction and Building Materials 29 708 3.095 2020 8.194 2 1 - European Journal of Operational Research 1 448 28.295 2014 6.598 - 3 1 International Journal of Coal Geology 1 480 16.186 2012 7.387 - 2 2 International Journal of Pavement Engineering 11 169 2.218 2018 4.088 4 - - Journal of Cleaner Production 16 395 3.618 2020 11.016 3 5 - Journal of Materials in Civil Engineering 11 151 1.250 2018 4.077 5 - - Landscape and Ecological Engineering 1 175 10.096 2011 2.106 - - 5 Research in Transportation Economics 2 422 9.739 2010 3.172 - 4 - Sustainability 31 187 0.916 2020 4.089 1 - - Table 2. Categories of the sources leading the ranking. Source Categories 1 1 2 3 4 5 6 7 8 9 10 11 Advances Functional Materials X Cities X Construction and Building Materials X X X European Journal of Operational Research X International Journal of Coal Geology X International Journal of Pavement Engineering X X Journal of Cleaner Production X X X Journal of Materials in Civil Engineering X X X Landscape and Ecological Engineering X X Research in Transportation Economics X Sustainability X X Total journals per category 1 2 1 2 2 2 2 3 2 2 1 1 Categories: 1. BIODIVERSITY; 2. CONSTRUCTION AND BUILDING TECHNOLOGY; 3. ECOLOGY; 4. ENGINEERING, CIVIL; 5. ENGINEERING, ENVIRONMENTAL; 6. ENVIRONMENTAL SCIENCE; 7. GREEN AND SUSTAINABLE SCIENCE AND TECHNOLOGY; 8. MATERIALS SCIENCE, MULTIDISCIPLINARY; 9. OPERATION RESEARCH AND MANAGEMENT SCIENCE; 10. TRANSPORTATION SCIENCE AND TECHNOLOGY; 11. URBAN STUDIES. Appl. Sci. 2022,12, 12996 8 of 25 Figure 4shows a low number of connections between the journals in terms of citations, revealing both the cited wide spectrum of source categories and the fragmentation and multidisciplinary of the research field which links, for example, themes related with categories ENGINEERING-ENVIRONMENTAL, ENVIRONMENTAL SCIENCE, GREEN AND SUSTAINABLE SCIENCE AND TECHNOLOGY, OPERATION RESEARCH AND MANAGEMENT SCIENCE, ENGINEERING CIVIL and TRANSPORTATION SCIENCE AND TECHNOLOGY (Cluster integrated by Journal of Cleaner Production,International Journal of Pavement Engineering and European Journal of Operational Research),CONSTRUCTION AND BUILDING TECHNOLOGY, MATERIAL SCIENCE and ENGINEERING CIVIL (Cluster integrated by Construction and Building Materials and Journal of Materials in Civil Engineering) or ENVIRONMENTAL SCIENCE, GREEN AND SUSTAINABLE SCIENCE AND TECHNOLOGY and OPERATION RESEARCH AND MANAGEMENT SCIENCE (Cluster integrated by Research in Transportation Economics and Sustainability). Appl. Sci. 2022, 12, x FOR PEER REVIEW 9 of 28 SCIENCE; 7. GREEN AND SUSTAINABLE SCIENCE AND TECHNOLOGY; 8. MATERIALS SCIENCE, MULTIDISCIPLINARY; 9. OPERATION RESEARCH AND MANAGEMENT SCIENCE; 10. TRANSPORTATION SCIENCE AND TECHNOLOGY; 11. URBAN STUDIES. Figure 4 shows a low number of connections between the journals in terms of citations, revealing both the cited wide spectrum of source categories and the fragmentation and multidisciplinary of the research field which links, for example, themes related with categories ENGINEERING-ENVIRONMENTAL, ENVIRONMENTAL SCIENCE, GREEN AND SUSTAINABLE SCIENCE AND TECHNOLOGY, OPERATION RESEARCH AND MANAGEMENT SCIENCE, ENGINEERING CIVIL and TRANSPORTATION SCIENCE AND TECHNOLOGY (Cluster integrated by Journal of Cleaner Production, International Journal of Pavement Engineering and European Journal of Operational Research),CONSTRUCTION AND BUILDING TECHNOLOGY, MATERIAL SCIENCE and ENGINEERING CIVIL (Cluster integrated by Construction and Building Materials and Journal of Materials in Civil Engineering) or ENVIRONMENTAL SCIENCE, GREEN AND SUSTAINABLE SCIENCE AND TECHNOLOGY and OPERATION RESEARCH AND MANAGEMENT SCIENCE (Cluster integrated by Research in Transportation Economics and Sustainability). Figure 4. Network relationship of sources in terms of total citations. Table 3. Main authors in terms of publication count, total citations, and average normalised citations. Author N° Documents Total Citations Average Normalised Citations Average Publication Year Ranking Position Publication Counts Total Citations Average Normalised Citations Arulrajah A. 8 264 2.870 2019 5 - - Bektaş T. 1 448 28.295 2014 - 3 1 Berthelot C. 9 50 0.449 2013 3 - - Dai S. 2 681 12.794 2012 - 1 - Demir E. 1 448 28.295 2014 - 4 2 Hainin M.R. 11 106 0.656 2015 2 - - Huang X.-L. 1 323 15.109 2013 - - 4 Laporte G. 1 448 28.295 2014 - 5 3 Liu Q.-C. 1 323 15.109 2013 - - 5 Santos J. 9 228 2.050 2018 4 - - Seredin V.V. 2 681 12.794 2012 - 2 - Wang D. 12 50 0.543 2019 1 - - Table 3 shows the main authors in terms of the publication count, total citations, and average normalised citations and then, the most influential in the research field, particularly Demir E. and Laporte G., who are included in two of the rankings—total citations and average normalised citations. Wang D. has the highest number of published documents (12), followed by Hainin M.R. (11). In terms of total citations, Dai S. and Seredin V. lead the ranking with 681 citations, and Bektaş T., Demir E. and Laporte G. show the highest average Figure 4. Network relationship of sources in terms of total citations. Table 3. Main authors in terms of publication count, total citations, and average normalised citations. Author N◦ Documents Total Citations Average Normalised Citations Average Publication Year Ranking Position Publication Counts Total Citations Average Normalised Citations Arulrajah A. 8 264 2.870 2019 5 - - Bekta¸s T. 1 448 28.295 2014 - 3 1 Berthelot C. 9 50 0.449 2013 3 - - Dai S. 2 681 12.794 2012 - 1 - Demir E. 1 448 28.295 2014 - 4 2 Hainin M.R. 11 106 0.656 2015 2 - - Huang X.-L. 1 323 15.109 2013 - - 4 Laporte G. 1 448 28.295 2014 - 5 3 Liu Q.-C. 1 323 15.109 2013 - - 5 Santos J. 9 228 2.050 2018 4 - - Seredin V.V. 2 681 12.794 2012 - 2 - Wang D. 12 50 0.543 2019 1 - - Table 3shows the main authors in terms of the publication count, total citations, and average normalised citations and then, the most influential in the research field, particularly Demir E. and Laporte G., who are included in two of the rankings—total citations and average normalised citations. Wang D. has the highest number of published documents (12), followed by Hainin M.R. (11). In terms of total citations, Dai S. and Seredin V. lead the ranking with 681 citations, and Bekta¸s T., Demir E. and Laporte G. show the highest average normalised citation scores (28.2947). With the objective of analysing the collaboration between authors, the mapping of co-authorship by authors with a minimum of 1 document and 35 citations has been analysed, resulting in 172, as summarised in Figure 5a. A total of 36 sets of collaboration groups of authors were identified, with the highest number being 14 authors in cluster 1 (in red). Finally, the mapping of co-authorship by countries with a minimum of 10 documents (Figure 5b) revealed 3 scientific communities in the clusters in red, green, and blue, which include 7, 6, and 4 countries, respectively. The USA, United Kingdom, Canada, Australia, and China are the countries with the highest number of relationships with other countries. These countries have been among the three rankings Appl. Sci. 2022,12, 12996 9 of 25 (Table 4), so they could be considered the most influential in the research field, especially Canada, which is included in all of them, followed by the USA and China, present in both the publication count and the total citations ranking, and the Netherlands, which is in both the total citations and average normalised citations ranking. Finally, Table 3shows that the USA, Canada, and the United Kingdom have been publishing in the research field for the longest time (2013 and 2014); in fact, these countries promoted most of the road rating systems in use [ 22 ]. However, China, India, Malaysia, and Spain have more recently been incorporated in this field (2018), although they have not yet defined their own systems. Appl. Sci. 2022, 12, x FOR PEER REVIEW 11 of 28 (a) (b) Figure 5. Network visualisation co-authorship with minimum 35 citations ( a ) and by countries with minimum 10 citations (b). Appl. Sci. 2022,12, 12996 16 of 25 respectively [ 22 ]. In relation to the material type, asphalt vs. concrete pavements is observed across the whole-time horizon, including ASPHALT in the first period as a motor term, and CONCRETE PAVEMENT as an emerging one. Both materials (ASPHALT and CONCRETE) appear in the second period in transversal quadrants, while MIXTURES appears as an emerging theme. Finally, MIXTURES and ASPHALT are observed in the third period, in the motor and, again, transversal quadrants, respectively. With increasing awareness of the environmental impact of road and highway construction and development there was growing interest among industry practitioners in coming up with sustainable initiatives [ 52 ]. In fact, in the second period, terms related to these concepts such as CARBON DIOXIDE and LIFE CYCLE ASSESSMENT are included in the transversal quadrant, or LIFE CYCLE as motor theme in the third period. Finally, terms related to the environmental impact and safety of the use of vehicles are highlighted, as another important pillar on which it is necessary to work to reduce emissions during the operation stage of road infrastructure, which could be identified as motor themes, as in the case of HYBRID VEHICLE in the first period, and ACCIDENT PREVENTION on the border between the highly developed and isolated and motor quadrants. Finally, terms identified in studies suggesting that the design quality and lifetime of roads depend closely on the comprehensive understanding of the infrastructure can be highlighted along the time horizon, specifically DESIGN, PROJECT MANAGEMENT, and HIGHWAY ENGINEERING, all of them in the motor quadrant. However, terms to identify how the climatic conditions of different territories can dislocate the constructed transportation facilities [ 53 ] have not been identified along the time period, showing that the implementation of this topic in the concept of roads sustainability is still emerging. Finally, a higher centrality value (X axis in Figure 9) shows a higher contribution of a theme to the development of the research field [ 54 ]. This is the case of themes related with transport in the first sub-period, including HYBRID VEHICLES and ROAD TRANSPORTATION SYSTEMS in the top positions with centrality values of 241.11 and 210.93, respectively, HIGHWAY PLANNING and PAVEMENT MANAGEMENT with 163.98 and 136.45 in the second sub-period, or COMPRESSIVE STRENGTH and MIXTURES with 86.04 and 75.98 centrality values in last sub-period. On the other hand, and according to the concept of density (Y axis in Figure 9), HYBRID VEHICLES, GREEN PAVEMENTS, and COMPRESSIVE STRENGTH are the themes with the greatest strength of internal relationships among all the keywords of the research theme, meaning that they are undergoing the highest development [54]. 3.3. A Review of Sustainable Roadways The scientometric evaluation has stated that road infrastructure sustainability is a broad topic and is linked to several topics that are very important in developing the concept of sustainable roads. These topics combine to form a broader definition of the concept of road infrastructure sustainability. According to the papers included in this research, the most relevant topics that give the sustainable roads theme a broader and more extensive concept are the use of materials for more sustainable pavements during the construction and maintenance stages, sustainable road transport and the use of tools to identify the level of sustainability, which will be analysed below. Besides, more recent research reveals that, nowadays, it is necessary to address the sustainability of road infrastructure also from the perspective of adaptation to climate change and smart intelligence concepts. In consequence, this study has recognised the following crucial issues in the current field of research, which have also been briefly reviewed in subsequent subsections: (i) sustainable road transport systems; (ii) materials for more sustainable pavements; (iii) tools for roads sustainability assessment; (iv) adaptation of road infrastructure to climate change; and (v) smart road infrastructure. Appl. Sci. 2022,12, 12996 17 of 25 3.3.1. Sustainable Road Transport Systems During the operational stage, traffic operation takes places in a complex system including road infrastructure, vehicles, vehicle operation, and weather conditions. In consequence, the improvement of traffic management and road safety are important roles in the sustainable road concept [ 55 ]. In fact, the sustainable road transport theme has been included in the keywords co-occurrence analysis in Cluster 1 (red), with the highest number of keywords. It includes a high number of keywords related with energy sources, fuels, electric vehicles, and also road systems, traffic, and transportation safety. In consequence, even though road transport plays an important role in economic development and social integration, it also affects negatively to the environment and society [ 56 ]. Thus, road transportation activities and facilities have impacts on the economy (traffic congestion, mobility barriers, accident damage and costs), society (human health impacts and community interaction) and the environment (air and water pollution, nonrenewable resources depletion) [ 57 ]. Besides, the classic approach to traffic design aims to increase the level of mobility, so it is important to plan transport infrastructure and cities without reducing the necessary traffic [ 58 ]. This is why the reduction of the emissions and energy use associated with the transport services is considered a strategic issue of energy policy [59]. As road transport, utilising a huge amount of fossil fuel is considered worldwide as a significant source of pollutant emissions [ 60 ], causing global warming and fossil fuel depletion. The total energy consumption, total number of fatalities, and greenhouse gases emissions are approaches to evaluate the development of sustainable road transport systems [ 61 ]. Therefore, countries must take more serious actions on CO 2 emission reduction and energy saving initiatives in this field [ 62 ]. In this sense, sustainable transport should contain a set of components to increase its efficiency with respect to environmental, social, and economic aspects [ 5 ]. Hence, the implementation of alternative transport fuels and vehicles is important in order to achieve energy saving and preserve air quality; thus, electric vehicles or eco-driving contribute significantly to sustainable road transport through cost reduction and environmental protection [ 63 ]. On the other hand, improvements to the rechargeable batteries of electric vehicles in their cycle life, in terms of their energy and power density, are important to increase electric energy storage to achieve a green road transportation system [ 44 ]. As a result, the vehicle electrification could provide GHG reduction potentials of 2–6% [ 50 ] of air pollution, and reduce noise, enabling pleasant and safer driving, and providing community welfare [64]. 3.3.2. Materials for More Sustainable Pavements The relevance of materials used in pavement have been highlighted in the analysis of themes and this topic is clearly identified in Cluster 2 (green) of the keywords cooccurrence analysis, including 54 keywords. It contains a huge number of keywords related to pavement, recycling, waste management and aggregates, identifying road sustainability through pavement design, the materials used, and waste recycling. Other stages, such as materials production and road maintenance and rehabilitation, contribute substantially to GHG emissions as well, highlighting the importance of optimizing the management of these stages. The construction, operation, and maintenance of pavements consume a huge amount of natural energy and material resources, inducing environmental impacts. In fact, asphalt, with an annual worldwide production of over 1 billion tons for paving operations, is one of the most extensively used materials in the road construction industry [45]. The scarcity and rising cost of aggregates have forced highway agencies to develop new engineering strategies in the pavement sector to reduce the costs of road pavements construction and maintenance and improve their environmental performance, by using solutions moving toward sustainable pavement practices [ 65 ]. The strategies developed include: the use of reclaimed asphalt pavement as an alternative pavement design for new construction, Appl. Sci. 2022,12, 12996 18 of 25 maintenance, and rehabilitation projects [ 66 ], as well as more recycled and environmentally friendly materials [67]. The use of reclaimed asphalt pavement as a recycled material in road construction is a valuable strategy to preserve natural energy and resources and to construct sustainable pavements [ 45 , 46 ]. In fact, in Europe, 47% of the available reclaimed asphalt pavement was utilised in warm or hot mix asphalt applications, and 22 million tons were utilised in other road construction applications stockpiles [ 68 ]. In USA, 71.8 million tons were accepted in 2011, 84% of which were utilised in road construction [ 69 ]. Because the recycled asphalt is not sustainable when degraded, whereas 100% hot mix asphalt performs the materials cycle by fully using the valuable materials in reclaimed asphalt in high quality road constructions [ 58 ], the reuse of hot recycling and construction waste results in good quality materials that can be used to construct sustainable and durable pavement structures [70]. On the other hand, reducing the virgin aggregate and binder content in warm and hot mix asphalt, reducing the emissions generated in mixture production and the energy consumed, and implementing preventive treatment are approaches to improving the sustainability of pavements [ 71 ]. To do that, some of the solutions mentioned in the literature are: long-lasting pavements [ 72 ]; industrial by-products and waste [ 73 ]; reclaimed asphalt pavement materials [ 74 ]; pavement preservation strategies [ 75 ]; and asphalt mixes requiring a lower manufacturing temperature [76]. Finally, alternative materials have been used for sustainable pavement, for example: stabilised quarry fines [ 77 ]; construction and demolition waste, fly ash, and jet grouting, as fillers [ 78 ]; fly ash as a stabiliser, which at 30% of total content improves the pavement resilience, although more than 30% reduces the pavement performance [ 66 ]; high pozzolanic mineral admixtures like silica fume could be used to make high quality pavement that is more economic, durable and environmentally friendly [ 79 ]; and rubber-modified asphalt improves the pavement performance in both low and high temperature conditions [ 80 ], providing a sustainable solution for the urban solid waste which is generated by waste tyres [81,82]. 3.3.3. Tools for Roads Sustainability Assessment With the increased concern about sustainability, several efforts have been made to develop assessment methods, indicators, assessment tools, and rating systems [ 34 ]. In fact, the sustainability assessment theme of Cluster 5 (purple) in the keywords co-occurrence analysis contains a large number of keywords related to life cycle assessment, environmental impact and costs. One of the most commonly applied techniques to measure the impacts of roadway design along its service life [ 83 ] is a life cycle assessment (LCA). The estimator in this approach divides the service life of the pavement into the following stages: material production, construction, maintenance, rehabilitation, and end of life. As LCA is related with measuring only the environmental impacts, life cycle sustainability assessment (LCSA) is considered an appropriate approach to evaluate the pavement sustainability, embracing environmental life cycle assessment (E-LCA), social life cycle assessment (S-LCA) and life cycle cost analysis (C-LCA) [ 84 ]. The pavement C-LCA, published by the American Association of State Highway and Transportation Officials (AASHTO) in 1960, and the pavement E-LCA framework have been widely developed [ 85 ]; however, pavement S-LCA is still in an underdeveloped state, but its integration into pavement management is highly recommended [86]. On the other hand, given that the implementation of sustainability in road infrastructure has become focused on providing measurements and guidance for including sustainable principles in road projects [ 21 ], the use of a rating system to meet certain mandatory and minimum prerequisites could be a useful tool [ 87 ]. In this sense, a dozen voluntary certification and rating systems have been developed to evaluate the level of sustainability of road or roadway design, construction, and maintenance, including: CEEQUAL, Envision, BE2ST in-Highways, GreenRoads, GreenLITES, Invest, GreenPave, I_LAST, STARS, IS, and Appl. Sci. 2022,12, 12996 19 of 25 LEED ND [ 22 ]. Despite these systems being based on a set of best practices and showing a potential for supporting road projects managers in achieving environmentally sustainable, resilient, and smart transportation road infrastructures [ 21 ], new research is required to better develop these systems [34]. 3.3.4. Adaptation of Road Infrastructure to Climate Change Climate change may present both opportunities and risks for the management of the road infrastructure network [ 29 , 88 ]. Thus, changes in climate can lead to a decrease of the stress imposed on roads, however the effects on roads as a consequence of climate change have been reported in terms of the effects of high temperatures, daily temperature variation, heat waves increase, thawing and thawing permafrost and freezing, precipitation increase, low precipitation and drought conditions, changes in yearly precipitations, rising sea levels, river flow patterns, more frequent storm cyclones, and increasing forest fires [ 28 ]. Some of the effects reported include: reduction of pavement life [ 28 , 89 ], thermal expansion at bridge joints [ 90 ], rutting of flexible pavements [ 31 , 91 ], longitudinal and fatigue pavement cracking [ 92 ], effects on pavement roughness [ 93 ], changes in landscape/biodiversity [ 28 ], landfill instability caused by thawing [ 94 ], roads sinking and pipelines, pavement layers and bridge collapse [ 95 ], occurrence of differential freezing [ 96 ], avalanches and rockslides [ 97 ], ground stability impacts [ 98 ], loss of soil cover [ 99 ], increased susceptibility to wildfires, risk of runoff flooding, landslides, slope failure [ 28 ], erosion of road platforms and adjacent land [ 99 ], submergence of roads [ 100 ], saturation of unbonded layers (Knott et al., 2019), erosion of the road base and its structures [ 28 ], and higher salinity which affects asphalt and blockage of drainage systems [99], among others. In consequence, preventive actions are necessary to protect and adapt road infrastructure against future impacts of climate effects and reduce maintenance costs [ 88 ]. Although Clusters 4 (yellow) and 6 (sky blue) in the keywords co-occurrence analysis include some keywords that could be related with effects of climate change, for example storms or drainage, the keyword adaptation has not been specifically identified among the most relevant themes. This means that the incorporation of the adaptation of road infrastructure to climate change is still an early stage in terms of sustainability. 3.3.5. Smart Road Infrastructure The term “smart” is the acronym for Self-Monitoring Analysis and Reporting Technology and it is used to describe the availability of innovative technologies in different scopes. The smart road concept refers to road infrastructure that improves its operational capability to meet the major challenge of connecting users, vehicles, and infrastructure in an intelligent, efficient, safe, and sustainable manner, as well as improve the maintenance of roads [ 33 ]. This concept means the use of Information and Communications Technologies (ICT) in road infrastructure operation and maintenance, which can transfer data in real time to avoid accidents and delays, and allow damage detection of pavements, etc., but also the use of so-called intelligent materials [33]. The key functions of the smart road, in terms of the use of ICT, are [ 33 ]: self-awareness, information connection, self-adaptability, and energy harvesting. Thus, sources such as drones, sensors, cameras, satellite systems, among others, installed in different components of a road infrastructure are Big Data resources [ 101 ] and allow the sharing of information, connection, and cooperation. For example, they can be installed in pavement for temperature, moisture or structure damage detection and sub-grade/soil settlement and slope monitoring [ 102 ]; but they can also be used for traffic flow monitoring and management [ 33 ] to provide feedback to traffic managers, but also to users of vehicles to support their decision-making, as well as being connected to autonomous vehicles in the future to allow automatic adaptation to the circumstances of the traffic, weather, etc. On the other hand, road infrastructure can be seen as a suitable scenario for the use of clean energy, with the promotion of the use of electric vehicles [ 103 , 104 ], but also for its production thanks to the collection of solar, thermal, and mechanical energy from pavements, sub-grade, and Appl. Sci. 2022,12, 12996 20 of 25 other infrastructures [ 105 ]. Finally, intelligent materials are considered to be materials that are aware of their state and properties, monitored automatically and maintained proactively, with the objective of reducing carbon emissions and the consumption of resources or energy, namely, to be environmentally responsible. For example, materials sensitive to light and temperature have been developed to paint road pavements [ 33 ]; on the other hand, materials with the self-healing or self-restoring abilities have been developed for pavements thanks to the use of nano-particles, induction heating, and rejuvenation [ 106 , 107 ]. Induction heating also represents an active research field in safety design for the electric melting of ice and snow [108]. In short, smart roads can achieve greater resilience of the infrastructure. In consequence, this concept should be included in researching the sustainability of road infrastructure, both for the development and application of technologies to support it, and for the development of a framework of indicators to evaluate the implementation level as a tool to define strategies for planning. However, the contribution of the smart road infrastructure concept to sustainability is still in the early stages of development; in fact, the co-occurrence analysis of this research has only identified a few keywords clearly related with it, for example, intelligent artificial in Cluster 5 (purple), which has been identified with the theme of sustainability assessment and intelligent systems, intelligent vehicles, electric vehicles, or traffic control in Cluster 1 (red), related to sustainable transport. 4. Conclusions This study summarised the state-of-the-art in sustainable roads by using a scientific metric evaluation of the literature and discussion of the results. As a result, the researchers were able to obtain the following set of relevant conclusions from the most reliable sources by using the scientific metric computational tool, which can be used as the starting point for the future research, plans and strategies to improve the sustainability and resilience of these infrastructures. The bibliometric review of 25 years of research on sustainable roads (1997–2021) has shown that this concept has been approached from different perspectives, such as energy conservation and construction materials, but also policy instruments to promote and support sustainable practices during all the stages of road infrastructure projects. The research field is led by countries integrated in still small and scattered scientific collaboration clusters, such as the one including the USA, United Kingdom, Canada, and Australia, which have promoted road rating systems in their territories, and which some other countries such as China have recently joined. The analysis of the themes of the research field has shown that the environmental and economic dimension of the LCA (E-LCA and C-LCA) is clearly developed along the different stages: construction, material production, maintenance, and end of life. Both of them are clearly developed themes related to innovation in construction materials to reduce the consumption of natural resources for roads, as well as the energy consumption and emissions production during the construction and maintenance stages, and with the objective of mitigating their effects on climate change. In this sense, a special mention is needed for the use of waste to replace some road construction materials, which contributes to circular economy principles. On the other hand, the reduction of energy consumption during the operation stage, as a result of fossil fuels use, is clearly displayed through means such as electric vehicles or energy efficiency, which are directly connected with the development of solutions to reduce the great contribution of road transportation to carbon dioxide emissions. However, the social life cycle assessment (S-LCA), which is only identified in themes related to traffic and road safety, is still in an early stage and its integration into road infrastructure management is highly recommended. The same gaps have been identified in the case of the integration of the concept of adaptation of road infrastructures to climate change. It is necessary to take into account that road infrastructures have long operational lifetimes that make them sensitive to climate variations over their time of use. However, they are still designed and managed on the Appl. Sci. 2022,12, 12996 21 of 25 basis of the existing climate at the time of their construction and historical climate data which does not take into account changes of climate in the short, medium, and long term, so this could be translated into an increase in social and economic maintenance costs in the future as a consequence of the damage that will occur to them. In this sense, smart roads will achieve greater resilience, not only because of the integration of new technologies as a fundamental element of these infrastructures, but also due to the development of smart materials with, for example, self-healing or self-restoring abilities, contributing to a more environmentally friendly infrastructure. In consequence, it is possible to conclude that the concept of sustainability of both new and existing road infrastructures, as well as the guidelines and rating systems in use, should be revised to address the resilience concept and rethink their design for the future in order to fulfil the important SDGs targets, as well as creating a cleaner and more competitive Europe, and reducing net greenhouse gas emissions during the next decades. Author Contributions: Conceptualisation, M.Z. and A.B.; methodology, M.Z.; software, A.A.; formal analysis, A.A. and M.Z.; writing—original draft preparation, A.A.; writing—review and editing, M.Z. and A.B.; visualisation, M.Z.; supervision, M.Z. All authors have read and agreed to the published version of the manuscript. Funding: This research was funded by the Spanish Ministerio de Educación y Formación Profesional, thanks to the schoolarship for stays of professors and senior researchers in foreign centres (PRX21-00291). Institutional Review Board Statement: Not applicable. Informed Consent Statement: Not applicable. Data Availability Statement: Not applicable. Conflicts of Interest: The authors declare no conflict of interest. References 1. Sarang, G. 14-Replacement of stabilizers by recycling plastic in asphalt concrete. Use Recycl. Plast. Eco-Effic. Concr. Woodhead Publ. Ser. Civ. Struct. Eng. 2019, 307–325. [CrossRef] 2. Aarhaug, J.; Gundersen, F. Infrastructure investments to promote sustainable regions. Transp. Res. Procedia 2017 ,26, 187–195. [CrossRef] 3. Gibbons, S.; Lyytikäinen, T.; Overman, H.G.; Sanchis-Guarner, R. New road infrastructure: The effects on firms. J. Urban Econ. 2019,110, 35–50. [CrossRef] 4. Laurance, W.F.; Clements, G.R.; Sloan, S.; O’Connell, C.S.; Mueller, N.D.; Goosem, M.; Venter, O.; Edwards, D.P.; Phalan, B.; Balmford, A.; et al. A global strategy for road building. Nature 2014,513, 229–232. [CrossRef] [PubMed] 5. Mesjasz-Lech, A.; Włodarczyk, A. The role of logistics infrastructure in development of sustainable road transport in Poland. Res. Transp. Bus. Manag. 2022,44, 100841. [CrossRef] 6. Nowicka-Skowron, M.; Kaczynska, M.E.; Dobrovsky, L. Road Transport Management and Innovations. Zesz. Nauk. Politech. Cz˛est. Zarz. 2019,35, 97–107. [CrossRef] 7. Ben, S.O. Significance of Road Infrastructure on Economic Sustainability. Int. J. Afr. Asian Stud. 2020,66. [CrossRef] 8. Mohanty, S.P.; Choppali, U.; Kougianos, E. Everything you wanted to know about smart cities: The Internet of things is the backbone. IEEE Consum. Electron. Mag. 2016,5, 60–70. [CrossRef] 9. Ivanová, E.; Masárová, J. Importance of road infrastructure in the economic development and competitiveness. Econ. Manag. 2013,18. [CrossRef] 10. Rooshdi, R.R.R.M.; Rahman, N.A.; Baki, N.Z.U.; Majid, M.Z.A.; Ismail, F. An Evaluation of Sustainable Design and Construction Criteria for Green Highway. Procedia Environ. Sci. 2014,20, 180–186. [CrossRef] 11. Spellerberg, I.F. Ecological Effects of Roads and Traffic: A Literature Review. Glob. Ecol. Biogeogr. Lett. 1998 ,7, 317–333. [CrossRef] 12. Galantinho, A.; Santos, S.; Eufrázio, S.; Silva, C.; Carvalho, F.; Alpizar-Jara, R.; Mira, A. Effects of roads on small-mammal movements: Opportunities and risks of vegetation management on roadsides. J. Environ. Manag. 2022 ,316, 115272. [CrossRef] [PubMed] 13. Wang, F.; Xie, J.; Wu, S.; Li, J.; Barbieri, D.M.; Zhang, L. Life cycle energy consumption by roads and associated interpretative analysis of sustainable policies. Renew. Sustain. Energy Rev. 2021,141, 110823. [CrossRef] 14. Development Asian Bank. Methodology for Estimating Carbon Footprint of Road Projects: Case Study: India; Development Asian Bank: Tokyo, Japan, 2010. 15. Spence, R.; Mulligan, H. Sustainable development and the construction industry. Habitat Int. 1995,19, 279–292. [CrossRef] Appl. Sci. 2022,12, 12996 22 of 25 16. Koletnik, D.; Lukman, R.; Krajnc, D. Environmental Management of Waste Based on Road Construction Materials. Environ. Res. Eng. Manag. 2012,59, 263–274. [CrossRef] 17. Espinoza-Molina, F.E.; Ojeda-Romero, C.F.; Zumba-Paucar, H.D.; Pillajo-Quijia, G.; Arenas-Ramírez, B.; Aparicio-Izquierdo, F. Road safety as a public health problem: Case of ecuador in the period 2000–2019. Sustainability 2021,13, 8033. [CrossRef] 18. Nalbandian, K.M.; Carpio, M.; González, Á. Analysis of the scientific evolution of self-healing asphalt pavements: Toward sustainable road materials. J. Clean. Prod. 2021,293, 126107. [CrossRef] 19. Shamsuddin Sabri, I.; Ali, M.N.B.; Aziz, R.A.; Ismail, I.M.E.H.B. Towards Better Contractor Performance to Achieve Sustainable Road Project Development. IOP Conf. Ser. Earth Environ. Sci. 2021,641, 012017. [CrossRef] 20. Giunta, M.; Mistretta, M.; Praticò, F.G.; Gulotta, M.T. Environmental Sustainability and Energy Assessment of Bituminous Pavements Made with Unconventional Materials. In Proceedings of the 5th International Symposium on Asphalt Pavements & Environment (APE); Pasetto, M., Partl, M.N., Tebaldi, G., Eds.; Springer International Publishing: Berlin/Heidelberg, Germany, 2020; pp. 123–132. 21. Muench, S.T.; Scarsella, M.; Bradway, M.; Hormann, L.; Cornell, L. Evaluating Project-Based Roadway Sustainability Rating System for Public Agency Use. Transp. Res. Rec. 2012,2285, 8–18. [CrossRef] 22. Mattinzioli, T.; Sol-Sánchez, M.; Martínez, G.; Rubio-Gámez, M. A critical review of roadway sustainable rating systems. Sustain. Cities Soc. 2020,63, 102447. [CrossRef] 23. United Nations. Transforming Our World: The 2030 Agenda for Sustainable Development United Nations; United Nations: New York, NY, USA, 2015. 24. Zhang, Y.; Luo, P.; Zhao, S.; Kang, S.; Wang, P.; Zhou, M.; Lyu, J. Control and remediation methods for eutrophic lakes in the past 30 years. Water Sci. Technol. 2020,81, 1099–1113. [CrossRef] [PubMed] 25. Attahiru, Y.B.; Aziz, M.M.A.; Kassim, K.A.; Shahid, S.; Wan Abu Bakar, W.A.; NSashruddin, T.F.; Rahman, F.A.; Ahamed, M.I. A review on green economy and development of green roads and highways using carbon neutral materials. Renew. Sustain. Energy Rev. 2019,101, 600–613. [CrossRef] 26. European Commission. European Green Deal Communication COM (2019) 640 Final; European Commission: Brussels, Belgium, 2019. 27. Bles, T.; Bessembinder, J.; Chevreuil, M.; Danielsson, P.; Falemo, S.; Venmans, A.; Ennesser, Y.; Löfroth, H. Climate Change Risk Assessments and Adaptation for Roads—Results of the ROADAPT Project. Transp. Res. Procedia 2016,14, 58–67. [CrossRef] 28. De Abreu, V.H.S.; Santos, A.S.; Monteiro, T.G.M. Climate Change Impacts on the Road Transport Infrastructure: A Systematic Review on Adaptation Measures. Sustainability 2022,14, 8864. [CrossRef] 29. Neumann, J.E.; Emanuel, K.; Ravela, S.; Ludwig, L.; Kirshen, P.; Bosma, K.; Martinich, J. Joint effects of storm surge and sea-level rise on US Coasts: New economic estimates of impacts, adaptation, and benefits of mitigation policy. Clim. Change 2015 ,129, 337–349. [CrossRef] 30. Neumann, J.E.; Price, J.; Chinowsky, P.; Wright, L.; Ludwig, L.; Streeter, R.; Jones, R.; Smith, J.B.; Perkins, W.; Jantarasami, L.; et al. Climate change risks to US infrastructure: Impacts on roads, bridges, coastal development, and urban drainage. Clim. Change 2015,131, 97–109. [CrossRef] 31. Qiao, Y.; Flintsch, G.W.; Dawson, A.R.; Parry, T. Examining Effects of Climatic Factors on Flexible Pavement Performance and Service Life. Transp. Res. Rec. 2013,2349, 100–107. [CrossRef] 32. Linkov, I.; Trump, B.D.; Trump, J.; Pescaroli, G.; Hynes, W.; Mavrodieva, A.; Panda, A. Resilience stress testing for critical infrastructure. Int. J. Disaster Risk Reduct. 2022,82, 103323. [CrossRef] 33. Pompigna, A.; Mauro, R. Smart roads: A state of the art of highways innovations in the Smart Age. Eng. Sci. Technol. Int. J. 2022 , 25, 100986. [CrossRef] 34. Sharifi, A. Urban sustainability assessment: An overview and bibliometric analysis. Ecol. Indic. 2021,121, 107102. [CrossRef] 35. Díaz-López, C.; Carpio, M.; Martín-Morales, M.; Zamorano, M. Analysis of the scientific evolution of sustainable building assessment methods. Sustain. Cities Soc. 2019,49, 101610. [CrossRef] 36. Lendra; Wibowo, M.A.; Hatmoko, J.U.D. Literature Review on Energy Consumption in Road Construction Projects. J. Phys. Conf. Ser. 2020,1625, 012034. [CrossRef] 37. Donthu, N.; Kumar, S.; Mukherjee, D.; Pandey, N.; Lim, W.M. How to conduct a bibliometric analysis: An overview and guidelines. J. Bus. Res. 2021,133, 285–296. [CrossRef] 38. Aghaei Chadegani, A.; Salehi, H.; Md Yunus, M.M.; Farhadi, H.; Fooladi, M.; Farhadi, M.; Ale Ebrahim, N. A comparison between two main academic literature collections: Web of science and scopus databases. Asian Soc. Sci. 2013,9, 18–26. [CrossRef] 39. Meho, L.I. Using Scopus’s CiteScore for assessing the quality of computer science conferences. J. Informetr. 2019 ,13, 419–433. [CrossRef] 40. Alam, S.; Kumar, A. Sustainability outcomes of infrastructure sustainability rating schemes for road projects. In Proceedings of the Australasian Transport Research Forum 2013 Proceedings, Brisbane, Australia, 2–4 October 2013. 41. Yang, H.; Liu, L.; Yang, W.; Liu, H.; Ahmad, W.; Ahmad, A.; Aslam, F.; Joyklad, P. A comprehensive overview of geopolymer composites: A bibliometric analysis and literature review. Case Stud. Constr. Mater. 2022,16, e00830. [CrossRef] 42. Su, H.N.; Lee, P.C. Mapping knowledge structure by keyword co-occurrence: A first look at journal papers in Technology Foresight. Scientometrics 2010,85, 65–79. [CrossRef] Appl. Sci. 2022,12, 12996 23 of 25 43. Demir, E.; Bekta¸s, T.; Laporte, G. A review of recent research on green road freight transportation. Eur. J. Oper. Res. 2014 ,237, 775–793. [CrossRef] 44. Huang, X.L.; Wang, R.Z.; Xu, D.; Wang, Z.L.; Wang, H.G.; Xu, J.J.; Wu, Z.; Liu, Q.C.; Zhang, Y.; Zhang, X.B. Homogeneous CoO on graphene for binder-free and ultralong-life lithium ion batteries. Adv. Funct. Mater. 2013,23, 4345–4353. [CrossRef] 45. Behnood, A. Application of rejuvenators to improve the rheological and mechanical properties of asphalt binders and mixtures: A review. J. Clean. Prod. 2019,231, 171–182. [CrossRef] 46. Chandrappa, A.K.; Biligiri, K.P. Pervious concrete as a sustainable pavement material—Research findings and future prospects: A state-of-the-art review. Constr. Build. Mater. 2016,111, 262–274. [CrossRef] 47. Silva, H.M.R.D.; Oliveira, J.R.M.; Jesus, C.M.G. Are totally recycled hot mix asphalts a sustainable alternative for road paving? Resour. Conserv. Recycl. 2012,60, 38–48. [CrossRef] 48. Cobo, M.J.; López-Herrera, A.G.; Herrera-Viedma, E.; Herrera, F. An approach for detecting, quantifying, and visualizing the evolution of a research field: A practical application to the Fuzzy Sets Theory field. J. Informetr. 2011,5, 146–166. [CrossRef] 49. Victory, W. A review on the utilization of waste material in asphalt pavements. Environ. Sci. Pollut. Res. 2022 ,29, 27279–27282. [CrossRef] [PubMed] 50. Huang, Y.; Wolfram, P.; Miller, R.; Azarijafari, H.; Guo, F.; An, K.; Li, J.; Hertwich, E.; Gregory, J.; Wang, C. Mitigating life cycle GHG emissions of roads to be built through 2030: Case study of a Chinese province. J. Environ. Manag. 2022 ,319, 115512. [CrossRef] 51. Hasan, A.; Hasan, U.; Whyte, A.; al Jassmi, H. Lifecycle Analysis of Recycled Asphalt Pavements: Case Study Scenario Analyses of an Urban Highway Section. CivilEng 2022,3, 242–262. [CrossRef] 52. Abd Rashid, M.H.S.; Zakaria, R.; Aminudin, E.; Adzar, J.A.; Shamsuddin, S.M.; Munikanan, V.; Alias, N.E.; Sooria, S.Z.; Saha, K.M. Critical green road criteria for Malaysia green rural road index. IOP Conf. Ser. Mater. Sci. Eng. 2020 ,849, 012039. [CrossRef] 53. Efimenko, V.N.; Efimenko, S.V.; Sukhorukov, A.V. Sciences in Cold and Arid Regions Accounting for natural-climatic conditions in the design of roads in western Siberia. Sci. Cold Arid. Reg. 2015,7, 307–315. [CrossRef] 54. Callon, M.; Courtial, J.P.; Laville, F. Co-word analysis as a tool for describing the network of interactions between basic and technological research: The case of polymer chemistry. Scientometrics 1991,22, 155–205. [CrossRef] 55. Ullah, I.; Szpytko, J. Effects of Improved Traffic Management on Sustainable Distributed Road Transportation Safety Based on Asian Experiences. J. KONBiN 2010,14–15, 321–332. [CrossRef] 56. Shen, Y.; Bao, Q.; Hermans, E. Applying an alternative approach for assessing sustainable road transport: A benchmarking analysis on eu countries. Sustainability 2020,12, 10391. [CrossRef] 57. Litman, T.; Burwell, D. Issues in sustainable transportation. Int. J. Glob. Environ. Issues 2006,6, 331–347. [CrossRef] 58. Zaumanis, M.; Mallick, R.B.; Frank, R. 100% recycled hot mix asphalt: A review and analysis. Resour. Conserv. Recycl. 2014 ,92, 230–245. [CrossRef] 59. Kelly, G.D. Avenues to Sustainable Road Transport Energy in New Zealand. 2015. Available online: https://ro.uow.edu.au/ gsbpapers/450 (accessed on 15 November 2022). 60. Huang, Y.; Ng, E.C.Y.; Zhou, J.L.; Surawski, N.C.; Chan, E.F.C.; Hong, G. Eco-driving technology for sustainable road transport: A review. Renew. Sustain. Energy Rev. 2018,93, 596–609. [CrossRef] 61. Shen, Y.; Ruan, D.; Hermans, E.; Brijs, T.; Wets, G.; Vanhoof, K. Sustainable Road Transport in the European Union: Changes in Undesirable Impacts. Transp. Res. Rec. 2011,2242, 37–44. [CrossRef] 62. Lacal Arantegui, R.; Jäger-Waldau, A. Photovoltaics and wind status in the European Union after the Paris Agreement. Renew. Sustain. Energy Rev. 2018,81, 2460–2471. [CrossRef] 63. Franke, T.; Arend, M.G.; McIlroy, R.C.; Stanton, N.A. What Drives Ecodriving? Hybrid Electric Vehicle Drivers’ Goals and Motivations to Perform Energy Efficient Driving Behaviors. In Advances in Human Aspects of Transportation; Stanton, N.A., Landry, S., di Bucchianico, G., Vallicelli, A., Eds.; Springer International Publishing: Berlin/Heidelberg, Germany, 2017; pp. 451–461. 64. Doorghen-Gorden, J.; Nowbuth, M.D.; Proag, V. Assessing the Implementation of Eco-Driving in Mauritius—A Climate Change Mitigation Measure. In The Nexus: Energy, Environment and Climate Change; Filho, W.L., Surroop, D., Eds.; Springer International Publishing: Berlin/Heidelberg, Germany, 2018; pp. 367–381. [CrossRef] 65. Luck, J.D.; Workman, S.R.; Coyne, M.S.; Higgins, S.F. Solid material retention and nutrient reduction properties of pervious concrete mixtures. Biosyst. Eng. 2008,100, 401–408. [CrossRef] 66. Saride, S.; Deepti, A.; Rao, T.S.; Sarath Chandra Prasad, J.; Dayakar Babu, R. Evaluation of Fly-Ash-Treated Reclaimed Asphalt Pavement for the Design of Sustainable Pavement Bases: An Indian Perspective. Geo-Congr. 2014 Tech. Pap. 2014 , 3676–3685. [CrossRef] 67. Hossain, M.U.; Wong, J.J.Y.; Ng, S.T.; Wang, Y. Sustainable design of pavement systems in highly urbanized context: A lifecycle assessment. J. Environ. Manag. 2022,305, 114410. [CrossRef] 68. EAPA. Asphalt in Figures 2007–2012; EAPA: Brussels, Belgium, 2012. 69. NAPA. Information Series 138 Annual Asphalt Pavement Industry Survey on Recycled Materials and Warm-Mix Asphalt Usage: 2009–2013 4th Annual Survey. 2014. Available online: www.asphaltpavement.org (accessed on 30 September 2022). 70. Molenaar, A.A.A. Durable and Sustainable Road Constructions for Developing Countries. Procedia Eng. 2013 ,54, 69–81. [CrossRef] 71. Santos, J.; Ferreira, A.; Flintsch, G. A multi-objective optimization-based pavement management decision-support system for enhancing pavement sustainability. J. Clean. Prod. 2017,164, 1380–1393. [CrossRef] Appl. Sci. 2022,12, 12996 24 of 25 72. Lee, E.-B.; Kim, C.; Harvey, J.T. Selection of Pavement for Highway Rehabilitation Based on Life-Cycle Cost Analysis: Validation of California Interstate 710 Project, Phase 1. Transp. Res. Rec. 2011,2227, 23–32. [CrossRef] 73. Carpenter, A.C.; Gardner, K.H.; Fopiano, J.; Benson, C.H.; Edil, T.B. Life cycle-based risk assessment of recycled materials in roadway construction. Waste Manag. 2007,27, 1458–1464. [CrossRef] [PubMed] 74. Aurangzeb, Q.; Al-Qadi, I.L.; Ozer, H.; Yang, R. Hybrid life cycle assessment for asphalt mixtures with high RAP content. Resour. Conserv. Recycl. 2014,83, 77–86. [CrossRef] 75. Giustozzi, F.; Crispino, M.; Flintsch, G. Multi-attribute life cycle assessment of preventive maintenance treatments on road pavements for achieving environmental sustainability. Int. J. Life Cycle Assess. 2012,17, 409–419. [CrossRef] 76. Rodríguez-Alloza, A.M.; Malik, A.; Lenzen, M.; Gallego, J. Hybrid input-output life cycle assessment of warm mix asphalt mixtures. J. Clean. Prod. 2015,90, 171–182. [CrossRef] 77. Zhang, Y.; Miksic, A.; Castillo, D.; Korkiala-Tanttu, L. Microstructural behaviour of quarry fines stabilised with fly ash-based binder. Road Mater. Pavement Des. 2022, 1–14. [CrossRef] 78. Russo, F.; Veropalumbo, R.; Pontoni, L.; Oreto, C.; Biancardo, S.A.; Viscione, N.; Pirozzi, F.; Race, M. Sustainable asphalt mastics made up recycling waste as filler. J. Environ. Manag. 2022,301, 113826. [CrossRef] 79. Saini, S.K.; Ransinchung, G.D.; Kumar, P. Effect of Different Mineral Admixtures on the Performance of Pavement Quality Concrete Containing the Optimum Amount of Jarosite as Partial Replacement of Cement. Arab. J. Sci. Eng. 2022 ,47, 13523–13535. [CrossRef] 80. Xue, H.; Cao, Y.; Liu, Q.; Zhang, H.; Zhang, M. Stability Evaluation and Mechanism of Asphalts Modified with Various Rubber Powder Contents. Front. Mater. 2021,7, 622479. [CrossRef] 81. Tao, M.; Hao, W.; Liang, H.; Yongli, Z.; Xiaoming, H.; Jun, C. Property Characterization of Asphalt Binders and Mixtures Modified by Different Crumb Rubbers. J. Mater. Civ. Eng. 2017,29, 04017036. [CrossRef] 82. Zhang, J. An Overview of Sustainable Highway Infrastructure Development in Yunnan, China. IOP Conf. Ser. Mater. Sci. Eng. 2020,914, 012003. [CrossRef] 83. Huang, M.; Dong, Q.; Ni, F.; Wang, L. LCA and LCCA based multi-objective optimization of pavement maintenance. J. Clean. Prod. 2020,283, 124583. [CrossRef] 84. Zheng, X.; Easa, S.M.; Yang, Z.; Ji, T.; Jiang, Z. Life-cycle sustainability assessment of pavement maintenance alternatives: Methodology and case study. J. Clean. Pro. 2019,213, 659–672. [CrossRef] 85. Babashamsi, P.; Md Yusoff, N.I.; Ceylan, H.; Md Nor, N.G.; Salarzadeh Jenatabadi, H. Evaluation of pavement life cycle cost analysis: Review and analysis. Int. J. Pavement Res. Technol. 2016,9, 241–254. [CrossRef] 86. Santos, J.; Flintsch, G.; Ferreira, A. Environmental and economic assessment of pavement construction and management practices for enhancing pavement sustainability. Resour. Conserv. Recycl. 2017,116, 15–31. [CrossRef] 87. Sarsam, S.I. Sustainable and Green Roadway Rating System. Int. J. Sci. Res. Environ. Sci. 2015,3, 99–106. [CrossRef] 88. Neumann, J.E.; Chinowsky, P.; Helman, J.; Black, M.; Fant, C.; Strzepek, K.; Martinich, J. Climate effects on US infrastructure: The economics of adaptation for rail, roads, and coastal development. Clim. Change 2021,167, 44. [CrossRef] 89. Knott, J.F.; Sias, J.E.; Dave, E.V.; Jacobs, J.M. Seasonal and Long-Term Changes to Pavement Life Caused by Rising Temperatures from Climate Change. Transp. Res. Rec. 2019,2673, 267–278. [CrossRef] 90. Evans, C.; Tsolakis, D.; Naude, C. Framework to Address the Climate Change Impacts on Road Infrastructure Assets and Operations. In Proceedings of the Australasian Transport Research Forum (ATRF), 32nd, 2009, The Growth Engine Interconecting Transport Performance, the Economy and the Environment, Auckland, New Zealand, 29 September–1 October 2009. 91. Tighe, S.L.; Smith, J.; Candidate, M.; Mills, B.; Andrey, J. Using the MEPDG to Assess Climate Change Impacts on Southern Canadian Roads. 2008. Available online: https://trid.trb.org/view/1214378 (accessed on 30 September 2022). 92. Kim, S.; Ceylan, H.; Heitzman, M. Sensitivity Study of Design Input Parameters for Two Flexible Pavement Systems Using the Mechanistic-Empirical Pavement Design Guide. In Proceedings of the 2005 Mid-Continent Transportation Research Symposium, Ames, IA, USA, 18–19 August 2005. 93. Graves, R.C.; Mahboub, K.C. Pilot Study in Sampling-Based Sensitivity Analysis of NCHRP Design Guide for Flexible Pavements. Transp. Res. Rec. 2006,1947, 122–135. [CrossRef] 94. Van der Sluijs, J.; Kokelj, S.V.; Fraser, R.H.; Tunnicliffe, J.; Lacelle, D. Permafrost terrain dynamics and infrastructure impacts revealed by UAV photogrammetry and thermal imaging. Remote Sens. 2018,10, 1734. [CrossRef] 95. Larsen, P.H.; Goldsmith, S.; Smith, O.; Wilson, M.L.; Strzepek, K.; Chinowsky, P.; Saylor, B. Estimating future costs for Alaska public infrastructure at risk from climate change. Glob. Environ. Change 2008,18, 442–457. [CrossRef] 96. Côté, J.; Konrad, J.M. A numerical approach to evaluate the risk of differential surface icing on pavements with insulated sections. Cold Reg. Sci. Technol. 2005,43, 187–206. [CrossRef] 97. Jacobsen, J.K.S.; Leiren, M.D.; Saarinen, J. Natural hazard experiences and adaptations: A study of winter climate-induced road closures in Norway. Nor. Geogr. Tidsskr. 2016,70, 292–305. [CrossRef] 98. Argyroudis, S.A.; Mitoulis, S.; Winter, M.G.; Kaynia, A.M. Fragility of transport assets exposed to multiple hazards: State-of-the-art review toward infrastructural resilience. Reliab. Eng. Syst. Saf. 2019,191, 106567. [CrossRef] 99. Dawson, A. Anticipating and Responding to Pavement Performance as Climate Changes. In Climate Change, Energy, Sustainability and Pavements; Gopalakrishnan, K., Steyn, W.J., Harvey, J., Eds.; Springer: Berlin/Heidelberg, Germany, 2014; pp. 127–157. [CrossRef] Appl. Sci. 2022,12, 12996 25 of 25 100. Nazarnia, H.; Nazarnia, M.; Sarmasti, H.; Wills, W.O. A systematic review of civil and environmental infrastructures for coastal adaptation to sea level rise. Civ. Eng. J. 2020,6, 1375–1399. [CrossRef] 101. Cavanillas, J.M.; Curry, E.; Wahlster, W. New Horizons for a Data-Driven Economy A Roadmap for Usage and Exploitation of Big Data in Europe; Springer: Berlin/Heidelberg, Germany, 2016. 102. Zhao, H.; Wu, D. Definition, Function, and Framework Construction of a Smart Road. New Front. Road Airpt. Eng. 2016 , 204–218. [CrossRef] 103. Sendek-Matysiak, E. Electric cars as a new mobility concept complying with sustainable development principles. AIP Conf. Proc. 2019,2078. [CrossRef] 104. Sendek-Matysiak, E. The Role and Importance of Electric Cars in Shaping a Sustainable Road Transportation System. In Research Methods and Solutions to Current Transport Problems; Siergiejczyk, M., Krzykowska, K., Eds.; Springer International Publishing: Berlin/Heidelberg, Germany, 2020; pp. 381–390. 105. Wang, H.; Jasim, A.; Chen, X. Energy harvesting technologies in roadway and bridge for different applications—A comprehensive review. Appl. Energy 2018,212, 1083–1094. [CrossRef] 106. Inozemtcev, S.; Korolev, E. Review of Road Materials Self-healing: Problems and Perspective. IOP Conf. Ser. Mater. Sci. Eng. 2020 , 855, 012010. [CrossRef] 107. Tabakovi´c, A.; Schlangen, E. Self-Healing Technology for Asphalt Pavements. In Self-Healing Materials; Hager, M.D., van der Zwaag, S., Schubert, U.S., Eds.; Springer International Publishing: Berlin/Heidelberg, Germany, 2016; pp. 285–306. [CrossRef] 108. Wang, X.; Wong, Y.D.; Yuen, K.F.; Li, K.X. Environmental governance of transportation infrastructure under Belt and Road Initiative: A unified framework. Transp. Res. Part A Policy Pract. 2020,139, 189–199. [CrossRef]