diff --git a/nav2_planner/src/planner_server.cpp b/nav2_planner/src/planner_server.cpp
index cb2e87b7463..af28b1b1eb0 100644
--- a/nav2_planner/src/planner_server.cpp
+++ b/nav2_planner/src/planner_server.cpp
@@ -644,7 +644,8 @@ void PlannerServer::isPathValid(
 
     /**
      * The lethal check starts at the closest point to avoid points that have already been passed
-     * and may have become occupied
+     * and may have become occupied. The method for collision detection is based on the shape of 
+     * the footprint. 
      */
     std::unique_lock<nav2_costmap_2d::Costmap2D::mutex_t> lock(*(costmap_->getMutex()));
     unsigned int mx = 0;