Systematic Review of Literature on Dry Port-Concept Evolution

e-mail: nabil.lamii.01@gmail.com Dry port plays an important role in supply chain management and mitigates seaport problems. The aim of this paper is to review the dry port concept over the different phases. Today there are different types of dry ports, different interpretations on the dry port life cycle, and different relations with seaport. We will provide a clear vision on the concept development and the advantages that can be added to the seaport and transportation flow. Then, the study will show the evolution of the research community interest on the concept. In the first step, we will briefly present all the challenges faced by seaports today. Next, we will undertake a systematic literature review in order to provide a global vision able to answer questions concerning dry port concept, types, research evolution. Finally, we will present some research topics that open for us at the dry port seaport system. Systematic Review of Literature on Dry Port Concept Evolution


INTRODUCTION
Since the 1970s, the world has experienced an acceleration of interconnections between the different geographical zones of the world. Today it can be defined with the concept of globalisation. It summarizes all flows, capitals, information, technology and goods beyond the national level to form an interconnected global network (Hirst et al., 2009). The global economy today has broken several geographical, technological and political barriers, and gives the global supply chain the capability to be developed in a remarkable way, and to open a new dimension such as the internationalisation of industrial production. As the world has changed since 1970, the international market is becoming increasingly global because of many factors such as the positive evolution of the world economy and the internationalisation of industrial production (UNCTAD, 2018). This is subsequently reflected in the growing demand for the maritime transport services, which has also experienced an unprecedented evolution, as shown in Figure 1 (UNCTAD, 2018), by pushing the maritime transport structure to cope with the global economy .
For this reason, the structure of maritime transport has gone through several transitional phases. One of the most significant phases is containerisation concept emergence, which has clearly contributed to the evolution of maritime transport (Berg and Langen, 2015).
Following the growth of the world economy, the volume of merchandise transported by sea is increasing every year ( Figure  1). This can amplify the seaport challenges like the increasing difficulty of container management, lack of space, congestion at seaports access points, and negative environmental impacts.
In the remainder of this paper, Section 2 presents an overview of seaport challenges. Dry port concept is defined in Section 3. In Section 4, we propose a systematic literature review in order to give a global vision about the concept development. The results of the research development are presented in Section 5. The concluding remarks and discussion are provided in Section 6.

AN OVERVIEW OF SEAPORT CHALLENGES
The seaport is the most important node in the international transportation chain. In general, with the growth of the world economy, the demand for the maritime transport services is increasing considerably (Figure 1), which raises challenges for the seaport.
As a result, it is normal to bring more importance on seaport evolution which becomes more and more critical (Mabrouki et al., 2014). Dry port existence has become a solution for seaport problems. Thus, dry port performance is linked to the seaport performance and with a large vision is linked to the dry portseaport system .
In other words, the understanding of the seaport challenges leads us to recognise the dry port necessity and functioning. In Table 1, the most important seaport challenges are listed.
The critical role that seaport plays in the global supply chain requires an adequate solution to optimize the performance of its services in order to overcome these challenges (Table 1). Dry port can improve significantly the performance of the seaport. Therefore, the performance of the dry port seaport system raises Maritime transport services evolution (UNCTAD, 2018). . Consequently, in order to increase seaport performance, we need to develop more the dry port concept. It represents an intermodal terminal directly connected to the seaport, with high-capacity means of transport, where customers can leave/pick up their goods as if heading directly to a seaport Wiegmans et al., 2015). This gives us a relevant solution for optimising seaport services and transforming it to a more efficient system such as the seaport dry port system.
The main purpose of this systematic literature review is to have a global vision of the dry port concept, and its advantages that can increase the efficiency of the seaport services and the whole transportation chain. We propose to achieve this objective by answering the following questions: • What are the existing definitions of dry port concept? • How has the dry port concept evolved over time?

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What are the functions and actors of dry port? • What are the advantages provided by the seaport dry port system? • How has the research on the concept of dry port developed? • What are the methods that research focuses on when it deals with the dry port concept? • Which countries are interested in the dry port concept and how?
• What are the journals and authors interested in the concept of the dry port?
Answering these questions will allow a deep understanding of e.g. dry port concept, role, functions, importance, interactions, and stakeholders.  The most cited definitions of dry port concept.

Seaport challenges Causes
The difficulties of managing goods today -The growth of the world economy (Hirst et al., 2009).
Lack of space -The steady increase in the volume of merchandise trade (UNCTAD, 2018).
-The increase in containerisation and its negative effects such as the increase of the containers' number in distress (Berg and Langen, 2015;UNCTAD, 2018).
-Urban growth at the entourage of seaports, which prevents seaport expansion.  -The different types of goods handled add their effect on the layout: The separation of different types of goods for safety purposes (dangerous goods and zones without dangerous goods), reefer containers, etc.  -The higher these types of goods in a terminal, the lower are the space for other goods: containers with dangerous goods cannot be stacked as high as non-dangerous containers, and the same happens with empty containers. (Hervás-Peralta et al., 2019) Congestion at seaport access at trucks' entrance -The large number of containers accommodated and shipped at the same time.  -Loading and unloading time.
-The insufficient number of access routes to the terminal service of certain seaports.

The increase of transport costs
Non-optimal management of transport flows between seaports and shippers .

Negative environmental impact
The high number of trucks that have a negative environmental impact. .

Definitions
Since the appearance of the dry port concept, researchers have mentioned several definitions with small differences that developed over time. It is e.g. the type of connection between dry port and seaport.  in their definition claim the rail as the only type of connection between seaport and dry port. However,  added the road as a connection in their definition. Then,  used the waterway as a possible type of connection. Table  2 summarises the most cited definitions.
The past period of research on the dry port topic definitions have shown that the concept is visibly much more fertile than we expect.

Source
Year Definitions Determinants (UNCTAD, 1991) 1991 Dry port is located near inland from seaports. It is linked directly to seaport or, in the case of international land movement, is in contact with the sources of imports and destination of exports. Dry ports may be used either in a country that has seaports or in landlocked country, but only surface transport modes are involved in giving access to dry port.
Connected to seaport by surface transport modes.

2004
The dry port concept is based on a seaport directly connected with inland intermodal terminals by rail where goods in intermodal loading units can be turned in as if directly to the seaport.
Connected to seaport principally by rail.

2007
A dry port is a port situated in the hinterland servicing an industrial/commercial region connected with one or several seaports by rail and/or road transport and is offering specialized services between the dry port and the transmarine destinations. Normally the dry port is containers and multimodal oriented and has all logistics facilities, which is needed for shipping and forwarding agents in a port.
Connected to seaport by rail and/or road transport and is offering specialized services.

(Roso et al., 2009) 2009
The dry port concept is based on a seaport directly connected by rail to inland intermodal terminals, where shippers can leave and/or collect their standardized units as if directly at the seaport.
Connected to seaport by rail and is offering same services as seaport.

(Ng and Girish, 2009) 2009
Dry port can be understood as an inland setting with cargohandling facilities to allow several functions to carry out, for example, cargo consolidation and distribution, temporary storage of containers, custom clearance, connection between different transport modes, allowing agglomeration of institutions (both private and public) which facilitates the interactions between different stakeholders along the supply chain, etc.
Connected to seaport by different transport modes, allowing agglomeration of institutions both private and public.

(Witte et al., 2019) 2019
Inland ports or dry ports is an inland facility with or without an intermodal terminal and logistics companies, which is directly connected to the seaport(s) with high capacity transport mean (s) either via rail, road or inland waterways, where customers can leave/pick up their standardized units as if directly to a seaport Connected to seaport by rail, road or inland waterways, same services as seaport.

Dry Port Roles
The establishment of the dry port brings a number of advantages to the seaport performance and touches upon other aspects. Table 3 sheds light on the advantages of the dry port.
As an option to decrease congestion, seaport challenges, and reduction in transportation cost, dry ports have a key role to play in advancing seaport connectivity.

Dry Port Functions
In general, the dry port functions are similar to the seaport except for the connection with the sea. They are replaced with other functions related to other transport means, essentially railway, but sometimes waterway or road are also considered. Figure 2 presents the major dry port functions.
According to Crainic et al. (2015), dry port can assume three main types within the transport chain: satellite terminal, load centre, and transhipment facility. In order for the seaport to function successfully, it is required to develop not only the seaport infrastructure, but also dry port functions.

Seaport
Reduce congestion at access points; Facilitate inventory management; Positive influence on the cost of storage; Increase the storage capacity of goods; Facilitate and increase the speed of services.

City
Reduction of traffic congestion.
Environment Reduction of influence of CO2 caused by emissions from trucks.

Shippers
Reduce transportation cost; Reduce storage cost; Facilitate access to seaports.

Country (society)
Develop commercial transport flows; More benefits for landlocked countries; More jobs in areas near the dry port.

Rail way companies
Diversification of the commercial offer. Table 4.
Dry port type particularities.

Dry Port Types
The research community distinguishes between three types of dry ports based on the distance between seaport and dry port. Thus, they are named close dry port, mid-range dry port, and distant dry port ( Figure 3).
Each type has its own characteristics. Table 4 explains the particularities and the advantages .
There are different dry port types that correspond to different seaport configurations. Hence, different types of dry port have been developed in different regions Santarremigia et al., 2018). The types of dry ports play an essential role in the development process. As shown in Table 4, there are a number of competitive advantages that dry ports can supply to maintain seaport development.

Type
Distance to seaport Advantages Distant dry port More than 500 kilometres Transhipment -Transport over long distance; -Reduce traffic congestion ; -The distance factor plays a remarkable role on reducing the transportation costs and the negative impact on the environment. Crainic et al., 2015; Mid-range dry port Between 50 and 500 kilometres

Dry Port Life Cycle Development
In the earliest research on the dry port seaport system, the first mention of a graphic modelling of the system was in 2011, when Wilmsmeier et al. (2011) presented a model that clarifies the spatial evolution of the relation structure between the dry  port and the seaport (Figure 4). This model presents two types of connections. The inside-out development begins from the dry port, and the outside-in development starts from the seaport.
In addition, Bask et al. (2014) linked the model of Wilmsmeier et al. (2011) with the time factor in order to give a model of three phases: 1) Pre-phase, 2) Start-up phase, and 3) Growth phase, as shown in Figure 5.
Pre-phase is the phase of the dry port creation, where several basic questions arise, e.g. Is the existence of the dry port important? Is there a robust infrastructure and strategy that supports the creation of the dry port?
Start-up phase is the opening. It is the first step in the implementation of the dry port plans. At this stage, the actors involved discuss the execution process and the investment on the direction development.
Growth phases is the development of the dry port in an operational direction, e.g. the introduction of a diversity addedvalue activities and the increase of relations between the actors involved.
In 2016,  apply the Vernon (1966) theory of product life cycle to the dry port-seaport system, which involves a description of its phases as follows: Development phase: The recognition of dry port in the transportation structure is prepared. The first questions asked at this stage are about the necessity of the dry port. The managers of the dry port put together an implementation plan. The plan should define the targets and goals of the dry port over the short, intermediate, and long term.
Introduction phase: The introduction of a dry port position in the transport system with some services is finished. Activities are elementary. The geographic reach is limited to the adjacent city.
Growth phase: The dry port's services increase. Standardisation and process innovation are addressed and implemented. The dedicated regions of the dry ports increase. Dry port develops in the operational direction.
Maturity phase: The dry port activity increases at a slower rate. Competition in the market augments as the number of dry ports augments. The external competition increases simultaneously and in proportion with increased maturity. This phase includes three sub-phases, i.e.: Sub-phase (4.1): inside-out or outside-in (the case of one seaport with many dry ports). In this sub-phase, we witness the start of limited connections between the seaport and other dry ports, which represents a spatial development of one seaport with several dry ports.
Sub-phase (4.2): bidirectional development (the case of one seaport with many dry ports). This sub-phase represents the operational development direction of one seaport with many (4.1) Inside out and outside in (the case of one seaport with many dry ports).
(4.2) Bidirectional (the case of one seaport with many dry ports).
(4.3) Bidirectional network (the case of many seaports with many dry ports).
? dry ports, such as the development of a variety of added-value services, which makes the connection between seaport and the other dry ports more efficient. Sub-phase (4.3): bidirectional network (i.e. the case of many seaports with many dry ports). This sub-phase represents the operational development direction of many seaports with many dry ports.
Decline phase: This happens eventually when we arrive to the point of the limitations in feasible rationalization or when the improvement process in general is achieved.
In this phase, we can announce the decline of this system, and maybe a new concept will be created, which could be a direction of future research.
The life cycle of the dry port concept will help to make the research more comprehensive. However, as shown above, our literature research is still based on individual case studies. It is essential to conceptualise the progress of the dry port in a more systematic approach. Therefore, this review paper shows a systematic review of journal papers on the dry port progress between 1980 and 2020. We try to organise the concept of the dry port on different investigative levels.

SYSTEMATIC LITERATURE REVIEW
Dry port development has had additional consideration by researchers and academics all over the world. A systematic review by Bentaleb et al. (2015a) of the dry port development between 1986 and 2015 revealed that there is a lack of studies relating literature review of the dry port concept. We followed a process of seven steps (Figure 7). This facilitates the analysis of the review and provides possible answers to the questions.

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Step 1: Establishment of the time period In this step, we chose a time interval that starts from 1980 to 2020. The reason behind this choice is to have a more global vision on the concept of dry port, and because of the fact that before 1980 we did not find articles clearly related to the dry port concept.

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Step 2: Definition of the keywords Here we chose three keywords, i.e. Dry Port, Inland Port, and Inland Intermodal Terminal, which define the same concept.
Since each author uses one of these keywords to describe the concept of the dry port, we chose these three words to globalize research and increase the number of articles collected.

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Step 3: Choice of search engines The choice of search engines in the literature review remains as a very important step. In our case, we chose seven engines, i.e. Web of Science, Science direct, Google Scholar, IEEE Explore, Taylor & Francis, Jstor and Springer link, to expand the research scope of the literature review.

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Step 4: Collection of articles (674 articles) In this step, we started the collection of articles with two conditions. The first condition was that the document was a qualified journal article or a chapter (we did not include conference paper), and the second condition was that the title and the abstract of the document collected should be linked with one of the three chosen keywords.
When we typed a keyword in the search engines, each search engine displayed a certain number of results found in a limited number of pages. Table 5 presents the number of articles collected in each search engine whose titles and their abstracts directly related to the concept of the dry port, to arrive at a total of 674 documents collected.

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Step 5: Deletion of duplicate articles (297 remained articles) The keywords used (Dry Port, Inland Port, Inland Intermodal Terminal) are very similar, which justifies the high number of duplicate articles of the total number of documents collected. Therefore, in this step we deleted the duplicate articles.

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Step 6: Article reading and removal of the off-topic articles (125 removed articles) This step required accurate reading of each document to eliminate off-topic articles.

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Step 7: Preparation of data on systematic literature review (172 retained articles) This step represents the final phase of the data structuring process. It facilitates the analysis of the data, and provides the most important information about it. Due to this step, we can have a global idea about the dry port concept and answer the above mentioned questions easily.

Research Evolution
The goal of this section is to understand the evolution and to study tendency research about the dry port concept within the researchers' community. Consequently, based on the publication evolution of the selected papers, we can distinguish three major phases (Figure 8). Due to the limited number of published articles, we determine the first phase between 1980 and 2003. In this first phase, the treatment of the dry port concept is modest; we can explain this reticence by a lack of necessity of the dry port role. The second phase is between 2004 and 2010. It represents a remarkable point of evolution. The number of articles starts to increase clearly due to the increase in interest for the dry port role. Finally, the third phase is from 2011 until 2019. In this stage, the production of the articles related to the dry port concept significantly increases.
We can interpret this result by saying that the concept of the dry port becomes more important each year . It shows that each year the researchers gain knowledge of the importance of the dry port concept and how it represents a perfect solution of seaport problems.

Dry Port Research Themes Evolution
We made a classification of the selected articles according to eight topics (see Table 6). These topics came as results of brainstorming done by our research team in order to establish the most important topics that we could find in our systematic literature review to reinforce our future research on seaport dry port system.
The point from this classification is to have a vision on the most important topics or themes assessed in the dry port papers. We found that optimization, performance, concept, location management, sustainability, environmental impact, risk management, and financial impact are the most important topics in the systematic literature review.
Moreover, we can note that sometimes we found many themes in the same article.
However, as Figure 9 shows, the majority of the articles cover two topics, concept and performance of the dry port. That is due to the concept novelty, which explains some differences in the definitions of the dry port concept. In addition, researchers try to understand better the dry port performance and its impact.
In the articles that assess location management, we found that most of the criteria used are economic criteria, which focus primarily on the reduction of the cost of transport. Environmental criteria mainly deal with the positive impact of installing a dry port. Geographical or spatial criteria focus on the geographical accessibility and limitation. Social criteria assess the availability and skill level of the workforce, the policy that focuses on the policy of the country related to the chosen place and other criteria that change according to the context assessed in the article (Awad-Núñez et al., 2016;. Because of the multiple criteria of the location management problem, we noticed that most articles treated the location management of the dry port using hybrid approaches based on MCDM (multi-criteria decision making) methods like AHP, ELECTRE, Fuzzy ANP or MACBETH Roso et al., 2015;.
Subsequently, we realized the time projection of the themes, which gave us a vision on the temporal progress of each theme in the systematic literature review. Figure 10 shows the evolution of articles about the dry port concept over time and their domain of studies. However, after the year 2010, the number of articles that touch the performance aspect increased in a remarkable way. It could be explained by changing the research angle of vision. In the beginning, research treated the concept in a general way; then, we noticed a development of the topics treating other aspects of the dry port concept over time, e.g. dry port performance.
The main reason behind this development is that at first the concept was ambiguous and unknown. However, over time the importance of the dry port has become more interesting for the researchers, who revealed other themes of research, e.g. performance, in Bentaleb et al. (2015a), ; location management, in , , ; life cycle, in Bask et al. (2014), ; risk management, in Bentaleb et al.( 2015b), Gong and Liu (2020). Evolution of papers' number on dry port theme over time.

Dry Port Research Methods' Evolution
In this section, a classification is made according to eight sets of methods (Table 6). Each set represents a category of methods used. The goal is to clarify the methods used by the authors of the selected articles.
The eight sets of methods are: In this section, we made a time projection (Figure 11) of the method sets (Table 6). The point is to have a clear idea about the used methods' evolution. Moreover, as we can notice in Figure  11, most researchers relate their articles to some region, country or a precise dry port (set B) in order to give their research certain legitimacy which makes the set B the most dominant set over all the period of the systematic literature review.
In 2009, the sets of reviews and previews (A) using interviews/questionnaires (D) and databases, archives or reports (F) rank as the most used methods after the set of case studies (B). Then, the other sets of mathematical methods (E), computer software or computer languages (G), Graphic modelling (C), and the set of methods like SWOT/ benchmarking… (H) started to increase over time.
We can explain this order by the nature of development of the topics in Figure 10. In order to provide a clarification of the concept of the dry port, we return to literature review and archives. If we want to deal with the performance of the dry port or any other theme, interviews, mathematical methods, and other methods like SWOT, graphic modelling, etc. are used.
One of the most important findings that we noticed through our systematic literature review is the existence of four articles entirely dedicated to the dry port literature review Bentaleb et al., 2015c;. Each article gives us a different angle of view on the dry port concept (Table 7) starting in 2010 with . They present a literature review that gives us a clear vision of the concept of the dry port and the world's existing dry ports, which represents a good opportunity for any new practitioner or researcher who wants to start discovering the dry port concept. Then, in 2015, Bentaleb et al. (2015c) give us a systematic literature review based on five steps: 1) problem definition; 2) selection of journals based on the time period between 1986 and 2015, taking in consideration four research engines (Jstor, Sciencedirect, Scopus and Google Scholar); 3) selection of studies; 4) critical evaluation, and 5) synthesis that treats the concept of dry port. The most important points of this systematic literature review are the detailed description of the development of the decision level and an illustration of all the countries where researchers were interested in the dry port concept. Furthermore, in 2016,  focuse on four pillars in their literature review: 1) the development of the dry port concept; 2) classification and function type of the dry port and the functions that can add value to seaports; 3) technological processes that represent the activities at the terminal, which are conducted with the aim of better quality of cargo handling, and which require appropriate technological elements and real-time work; 4) location determination of inland terminals presenting some methods and criteria used to determine the location of inland terminals. Finally,  present a systematic literature review based on four steps: 1) They define the criteria for inclusion or exclusion of papers; 2) They made a systematic search of the scientific literature based on criteria determined; 3) They analysed the papers and retrieved the relevant information for the review; 4) They performed data analysis and synthesis. The most important points mentioned are: papers published across journals over time; a good view made on the papers published over time; papers by geographical focus over time, where they Table 7.
Dry port literature reviews.
give us an idea about geographical focus; papers by type of methodology over time, dividing the methodology types into six categories: case study, conceptual study, quantitative (modelling), quantitative (empirical), literature reviews and editorials; papers by type of definitions over time; 5) key authors and network collaborations, where they mention most authors contributing in www.scopus.com 80 the dry port research; 6) key themes and conceptual approaches over time, where they present tree major periods crossed with four main conceptual approaches globalization/supply chain, port regionalisation, directional development, and institutional governance. However, if we take all the literature reviews found until now on the dry port concept including this paper, we will notice that there are some common points, e.g. the development of the concept of the dry port or the published papers over time.
On the other hand, all these literature reviews complement each other. Each paper gives a different view on the dry port concept:  give a good overview on the existing dry ports; Bentaleb et al. (2015c) give the decision level of the articles between 1986 and 2015, and a detailed geographical description on the dry port concept research.  add a detailed description of the methods and criteria used to locate the dry port.  illustrate the key themes and conceptual approaches over time. In our paper, we try to give another vision of the themes used in the dry port research.
We add an overview of the life cycle of the dry port development and we try to optimise our systematic methodology of research. We choose our time interval between 1980 and 2019; then, we determine six research engines in order to have more articles evaluating the dry port concept. Therefore, we recommend for all future researchers or practitioners to start with these literature reviews in order to have a clear and complete vision on this interesting concept.
A literature review on the dry port concept contributes to defining the most important flows in the dry port research. Recent studies have shown that the concept is visibly more diversified and much more fertile. Still, as much of the literature is principally based on individual case studies, the research of dry ports has proven to particularly need more focus on operational aspect search, e.g. risk management, performance management, etc.

Relation Between Topics and Methods
In addition, a cross between the sets of methods and the topics/themes has been realised to get a clear vision of the methods used in each topic (Figure 11). This gave us a great combination in each topic/theme, e.g. in the topic of "concept" we found that the first set of methods used is B (case studies) in order to give legitimacy and realistic aspect to research in this theme. After that, the sets A (literature reviews) and F (return to archives) follow the set B to make a connection between the past and the present in the treatment of the dry port concept. The same reasoning goes for the other themes to make a clear vision on the most used methods in each theme.
Regarding the content of the articles about the relation between topics and methods, Figure 12 shows that cases studies (Set B) are the most treated topics that evoke performance, concept and localization aspects. Furthermore, we observe an important use of methods in relation with performance, concept and localization aspects. With regard to the topic graphic modelling (set C), computer software or computer languages (set G) and other analytical methods (set H) have not been a priority for the research community up to now.
Therefore, most documents are case studies focusing on dry port performance, followed by studies on concepts and localisation.  Table 9.
Top 20 countries in terms of contribution in the selected documents in the systematic literature review.

Dry Port Journals and Countries' Trending
In this section, the goal is to identify the most productive journals (Table 8) and countries (Table 9) in relation with the dry port concept. We made a classification of journals and countries according to the number of articles in the systematic literature review. Table 8 shows the most relevant journals found.
This part contains the dry port documents in different countries. Different dry port types were developed in different regions and countries. We accumulate papers from a geographic angle. Table 9 shows the top 20 countries in terms of contribution in the selected documents in the systematic literature review.
Within this trend, interest for the dry port is expanding mutually across the variety of journals covered as well as geographical level. As the recognised research gaps demonstrate, more attention could be covered in terms of further practical studies on the dry port topic.

Number of articles
Journal of Transport Geography 15

Maritime Policy and Management 12
Maritime Economics and Logistics 9 Research in Transportation Economics 9 Transportation Research Part E 7

6
Procedia -Social and Behavioral Sciences 5 Sustainability 5 the Asian journal of shipping and logistics 5 Russia 3 3

CONCLUSION AND DISCUSSION
Over time, the dry port concept has changed from a simple infrastructure exchange point to a real solution for the maritime transport. Dry port studies have also evolved in similar ways. In the end, we found out that the dry port seaport system has become a very interesting subject due to its important contribution in the intermodal transport and its advantages that it can add to the global supply chain management. As this paper reveals, each year the dry port is becoming increasingly attractive for researchers. This is reflected in the development of the dry port concept and the appearance of the dry port types. This evolution has generated a number of implications with regard to the dry port role and functions. The past period of research on the dry port topic definitions have shown that the concept is visibly much more fertile than we expect.
One rising and significant topic emphasised by this study concerns the investigation about dry port case studies and their relationship with the dry port performance. Therefore, this review paper shows a systematic review of journal papers on the dry port progress between 1980 and 2020 (172 considered articles). We have tried to organise the concept on different investigative levels. Based on the evolution and study tendency research as well as the publication evolution of the selected papers, we can distinguish three major phases. First, the research treats the concept in a general way; then, we note a development of topics related to other aspects of the dry port concept over time, like dry port performance. The main reason behind this development is that at first the concept was ambiguous and unknown. Still, over time the importance of the dry port has become more interesting. Within this trend, interest for the dry port as well as the geographical level is increasing mutually in a variety of journals covered. As the recognized research gaps demonstrate, more attention could be expected in terms of further practical studies on the dry port topic. However, as we notice in this paper, despite the development of research, some topics have not been considered adequately, e.g. risk management, environmental impact or the financial influence of the dry port. We notice that there are some gaps in the research about the dry port. Additionally, this article recommends researchers, academics, and professionals to focus more research on the dry port, opening some opportunities for future research on the dry port concept. Finally, it is also essential to present some limitations of this systematic review. A major aspect is the concentration of studies in journals without inclusion of conference papers.