The line joining places equal time taken to reach is called :

NCERT (2026-27): “Transport distance can be measured as: km distance or actual distance of route length; time distance or the time taken to travel on a particular route; and cost distance or the expense of travelling on a route. In selecting the mode of transport, distance, in terms of time or cost, is the determining factor. Isochrone lines are drawn on a map to join places equal in terms of the time taken to reach them.”