Road networks have been expanding at a dramatic pace in recent decades, driven by growing demand for resources, energy, and access to markets. However, roads can also open a Pandora’s box of environmental ills, the most significant of which may be habitat loss and fragmentation. The scale of habitat loss driven by roads is dependent on their capacity to promote travel, and hence outcomes differ for paved and unpaved roads and for different habitat types. Where habitat fragments remain intact, spiderweb-like road networks create edge effects and act as barriers to movement for disturbance-sensitive species of plants and animals. This fragmentation means large expanses of remaining habitats are highly degraded and have altered species composition and ecological function. A substantial proportion of all roads today are not recorded in existing roadmaps. With millions of kilometers of new roads expected worldwide in the near future, it will be vital to develop new methods to detect roads in order to document the effects of road-related habitat disruption, and develop strategic road plans to minimize these disruptions.