The construction, operation and maintenance of road infrastructures impact the environment in many ways. Monitoring road impacts is essential for the identification of new issues, tracking trends and implementing appropriate mitigation actions.

This report clarifies what is encompassed in the concept of monitoring. It is based on the results of a survey of current environmental monitoring practice among different countries and of a literature search.

Current practice of monitoring is presented for the different environmental fields: air, noise, water, biodiversity, etc. and is considered at the different phases of a project phase: planning, construction, operation.

Case studies illustrate best practice and show how monitoring can be a useful tool for the design and operation of a road infrastructure as well as for the mitigation of negative impacts on the environment.

The report presents a series of environmental indicators currently in use at national and international levels and makes recommendations for effective monitoring.