The article discusses the importance of monitoring the environmental impact of road and rail projects in Sweden. The focus is on the natural environment, not economics. Monitoring helps ensure environmental effects are acceptable, protect natural values, and improve decision-making. It is crucial to assess the need for monitoring holistically to understand the full impact of roads and railways. Special attention should be given to the construction phase and irreversible effects. Methodologies need to be developed to analyze monitoring data effectively. Good baseline data and critical evaluation of existing surveys are essential. The report covers monitoring of fauna, vegetation, soil, water, and landscape, and their interactions.