Evolution and Trend of Research on the Hydrogeomorphological Processes on Roads in the Last Decades: a Review

Abstract

Over time, roads have become an important study object. Several studies were carried out to understand the importance of roads on the hydrogeomorphological dynamics on hillslopes and watershed. Nonetheless, new gaps and new research methods emerged as research progressed on this subject. Therefore, to understand the evolution and new challenges of research on roads, a bibliographic review was prepared based on 300 articles searched in the Scopus platform considering the last two decades (2001–2010 and 2011–2020). We use keywords that refer to roads in the search field, e.g., soil erosion on roads, delivery rate, bank, rails, highways, abandoned roads, and road rehabilitation. The data were tabulated and separated according to the following themes: data collection method, study purposes, road types, and geographic location. Our main conclusions were a) in the 2000s, around 60% of surveys were carried out on unpaved roads and rural roads, mainly in roadbed features; b) In the 2010, occurred a decentralization on the research on rural roads from mainstream countries as US and Australia to Latin American countries e.g., Brazil and Middle East e.g., Iran; c) the studies in emerging countries, mostly tested known research methods in different landscapes of tropical climate; d) a new research perspective in recent decades have emerged, focusing on the influence of roads on the landscape’s dynamics. Finally, roads are recognized as a humanmade landscape signature and studies about nature and biodiversity conservation, particularly at watershed scale, must considered this anthropogenic feature.