Lane and pathway thickness: definition essay based on two case studies of Algerian transport projects. Planning and transport engineering have for a long time considered pathways and lanes as continuous lines connecting a point A to a point B. In terms of transport, those points are considered as places located in the space-time, while the link between them is considered as a "no-place" that should be reduced in terms of travel time or distance.This transport and mobility representation does not take into consideration the reality of pathways' territorial thickness. The latter relates on the first hand to the multiplicity of activities, temporalities and representations that are overlaid on each other like a palimpsest. On the other hand, thinking in terms of lines is quite reductive. It denies the fact that a line has a thickness that includes a part of the crossed territory on both sides of the line itself. This paper will contribute first to define the territorial thickness of pathways or lanes. It will distinguish between vertical and horizontal thickness. Then, the text will explore methods to identify and characterize it. Finally, through two case studies in Algeria, we will show how transport planning at local as well as regional scales denies this thickness and disturbs lanes and pathways systems.