Road infrastructure projects are essential for a country’s economic and social development. Due to the magnitude, the projects are associated with considerable economic investments that in the case of failure can seriously affect regions’ economies. Despite the importance, roads from different countries are affected by cost overruns, hence, it is essential to identify and analyze the causative factors to focus the search for mitigation solutions. There are several studies focused on the cost factors identification, however, studies are lacking that synthesize and analyze the frequency and importance with which the factors have been reported to obtain a phenomenon overview. Therefore, this paper focuses on analyzing the frequency and importance with which cost overrun factors are reported in road projects. The research method consisted of a systematic review compound of five principal stages: (1) question formulation; (2) searching of relevant documents; (3) document selection; (4) evidence collection, analysis and synthesis; and (5) results’ report. Thirty-eight cost overrun factors were identified and classified into 14 categories. According to the Influence Index, the five most important and frequent cost overrun factors were: (1) failures in design, (2) price variation of materials, (3) inadequate project planning, (4) project scope changes, and (5) design changes.

An efficient highway infrastructure network is a determining factor in promoting the socio-economic development of countries and regions. Highway planning activities are highly important because their results ensure that projects are delivered within budget, schedule, and scope. Therefore, academics and professionals have promoted various methodological and technological advances focused on improving highway planning processes, evidenced by many scientific documents that address the topic. Despite progress, few studies have focused on analyzing the state of the knowledge structure and the technological and methodological trends of the highway planning topic. Considering this gap, this study presents trends in highway planning and its knowledge structure based on a bibliometric analysis from January 2015 to September 2021. The research method is based on a bibliometric analysis composed of five main stages: (1) scope definition, (2) selection of bibliometric analysis techniques, (3) data collection, (4) bibliometric analysis execution, and (5) evidence analysis and synthesis. Information from 1703 journal papers was collected and analyzed. The findings show that the main trends of highway planning focus on life cycle analysis, computational tools, smart cities, sustainability issues, construction processes, new equipment and materials, and multi-objective optimization, among others. Thus, the findings of this study allow the reader to identify the methodological and technological trends in highway planning and their knowledge gaps to guide future studies in the field.

Linear infrastructure projects, including roads, tunnels, and railroads, are vital for the socioeconomic advancement of regions and nations. Given their large scale, these projects require significant resources, leading to substantial environmental impacts and demanding the collaboration of professionals from multiple disciplines. In this context, it is essential to adopt strategies that favor digitalization to enhance the sustainability of such projects by automating the analysis of various alternatives. Despite the proliferation of studies in this area, there needs to be more research synthesizing the main trends in digitalization and sustainability in linear projects. Given this knowledge gap, this study focuses on identifying and analyzing the main trends in digitalization and sustainability in the context of linear infrastructure projects. To this end, a comprehensive bibliometric analysis of a selected set of papers has been carried out. The research method follows five main steps: (1) scope definition, (2) selection of bibliometric analysis techniques, (3) data collection, (4) bibliometric analysis execution, and (5) evidence analysis and synthesis. An analysis of 419 documents was done, applying performance analysis and scientific mapping techniques. The results reveal that trends in digitalization and sustainability in linear projects can be categorized into five main clusters: road construction, road administration, life cycle analysis, digitalization of linear infrastructure, and sustainable development, leading this line of research towards computer-aided design technologies such as BIM, GIS, and computer vision to study sustainable development throughout the whole life cycle analysis of linear infrastructure projects.

Building Information Modeling (BIM) has been widely adopted in the building sector. However, it is still an emerging topic in road infrastructure projects despite its enormous potential to solve ongoing issues. While there have been several recent studies on BIM implementation in road projects, there is a lack of research analyzing the actual BIM Uses in road projects as reported in academic and technical documents. Considering this gap, this paper presents a systematic review of BIM Uses and complementary technologies to BIM in road infrastructure projects. The research method consisted of a systematic review composed of five stages: (1) question formulation, (2) searching of relevant documents, (3) document selection, (4) evidence collection, analysis, and synthesis, and (5) results report. A total of 384 documents were collected, from which 134 documents reporting BIM Uses on roads were analyzed. This study has two main contributions. First, 39 BIM Uses were identified, which are classified into nine categories: road design, traffic analysis, soil aspects, road safety, environmental issues, other engineering analysis, construction planning and analysis, cost analysis, and construction monitoring and control. Second, a set of 26 technologies complementary to BIM adoption in roads were identified, among the most prevalent of which are geographic information systems (GISs) and laser scanning. The results serve as a basis for researchers to learn about the status and propose future developments on BIM adoption in road infrastructure.

Delay is one of the most common and complex issues that adversely affect the performance of construction pro-jects. Although much research exists on project delay, only some studies have systematically summarized and compared the causes of delay by the project type. In addition, few studies have quantitatively combined the variability across studies and related them to the responsibilities of project stakeholders. This study conducted a meta-analysis to provide quantitative and reliable evidence on delay causes combining previous research. This study categorized the top ten causes of delay published in primary research studies, calculated the average aggregate relative important index (RII) of these causes, quantitatively summarized their impact on building and road projects using meta-analysis techniques, and linked them to stakeholder responsibility. Based on an initial 160 top ten-delay causes reported, the study aggregated them into sixteen factors and seven management areas. This research found a different prioritization of delays by project type. Overall, while "site management & technical processes" was the most critical delay factor for building projects, "external issue" was for road projects. The comparison by region shows that "skills, knowledge & experience" was the most critical factor for African studies, but "late delivery and material-equipment issues" was for Asian studies. These factors were related to project stakeholders for defining mitigation actions that led to better project performance. Finally, this study provides a first taxonomy of delays, where the previous causes reported in the literature were clustered into factors and management areas.