Roadless and low‐traffic areas are typically large, natural or semi‐natural areas that have no roads or few roads with low‐traffic volume. They are relatively unaffected by roads and subsequent developments, and therefore, represent relatively undisturbed ecosystems, which provide important benefits for biodiversity and human societies. Roadless areas are rapidly becoming rare across the globe due to construction of road networks that serve widely expanding human activity. With a few exceptions, roadless and low‐traffic areas are not considered in national or international legislation; and consequently, they have been widely neglected in transport planning. 3.1 Roadless areas contribute significantly to the preservation of biodiversity and ecosystem services. 3.2 Planning of new transport routes should identify existing roadless areas and avoid them. 3.3 Subsequent (‘contagious’) development effects of road construction should be avoided in roadless and low‐traffic areas. 3.4 Unnecessary and ecologically damaging roads should be reclaimed to enlarge roadless areas and restore landscape‐level processes. 3.5 It is crucial to systematically evaluate the need for and location of proposed roads and implement the principle of ‘no net loss’ of unfragmented lands when there is no alternative. An important question during planning is whether the proposed road is really needed, and if so, where should it be placed. When the dissection of a roadless area is absolutely unavoidable, measures to prevent contagious development should be implemented, as well as compensation measures to restore the same amount of unfragmented habitat.