Contemporary development studies recognize road networks as a key element in economic development, socioeconomic well-being, and poverty alleviation. However, the outcome of road construction projects has not always met the original goals of the project, has contributed substantially to environmental degradation, and in some cases has led to the loss of cultural traditions and marginalization of indigenous peoples. The World Bank, one of the main financiers of road construction projects, admits that there is a paucity of empirical evidence about the amount and quality of the benefits, who receives them, and how they are disperse, despite the numerous socioeconomic evaluations of road projects already conducted. Environmental studies have shown few, if any; positive environmental impacts of road construction projects. To date, there have been very few studies on the sociocultural impacts of roads and no studies on how all three spheres of impacts influence each other. My research seeks to fill this gap by evaluating the impacts of the recently completed (2008) Kali Ghandaki Road, and the ongoing construction of the Marsyangdi Road, along the Annapurna Circuit Trail in the Annapurna Conservation Area of Nepal. I conducted 231 interviews in 45 villages along the road alignments. Employing a multiple case study framework derived from quantitative and qualitative data and methods, I explored the following questions: What impacts are the new roads along the Annapurna Circuit Trail having on local communities? How do socioeconomic, sociocultural, and environmental factors influence each other in road construction projects? What adaptive strategies are communities' using to cope with the changes the road is bringing, and how do those strategies evolve? Given the complexity of the interaction of environmental, socioeconomic, and sociocultural spheres of road construction, I developed a Coupled Human and Natural Systems model of road impacts based on the analysis of Case Study 1. I then apply this model as a template to illuminate specific road impacts in each of the case studies. Based on this Coupled Human and Natural Systems model and the ten case studies I came to the following conclusions: • Road impacts cannot be accurately evaluated by analyzing only one sphere, such as socioeconomic impacts. • All three spheres of road impacts influence each other in complex interconnected couplings, requiring a Coupled Human and Natural Systems framework for analysis and interpretation. • Due to these complex couplings, the impacts of road construction in Nepal are dynamic and change over time, often have a lag effect, and cross spatial boundaries impacting coupled systems not only in the immediate area, but also areas scales of magnitude distant. • Road construction projects in Nepal have both positive and negative impacts in all three spheres, environmental, socioeconomic, and sociocultural and these impacts manifest over time producing short-term, medium, and long-term effects. • The combination of the above factors often result in road projects that have unintended and unforeseen impacts making predictions about their outcome largely speculative. • Finally, trails and roads are a fundamental component of every culture. They are essential to our survival and yet they are often taken for granted in developed countries. Considering the cumulative environmental and human history that lies beneath many of our modern roads, which were once ancient trade routes, I argue that roads are embedded with a coupled human and ecological memory that has become a fundamental component of the human psyche. These conclusions highlight the importance of viewing roads as if they were living organisms with their own ecosystem. As roads grow, connecting to other roads to form road networks, the road ecosystem also grows encountering other human and ecological ecosystems. To understand the multitude and complexity of interactions between these ecosystems requires a comprehensive framework that can bridge the different spheres of influence, such as the Coupled Human and Natural Systems model described in this thesis.