diff --git a/perception/heatmap_visualizer/include/heatmap_visualizer/heatmap_visualizer_node.hpp b/perception/heatmap_visualizer/include/heatmap_visualizer/heatmap_visualizer_node.hpp
index 88adf1d3d94b6..9ffb3349435e5 100644
--- a/perception/heatmap_visualizer/include/heatmap_visualizer/heatmap_visualizer_node.hpp
+++ b/perception/heatmap_visualizer/include/heatmap_visualizer/heatmap_visualizer_node.hpp
@@ -66,8 +66,8 @@ class HeatmapVisualizerNode : public rclcpp::Node
   float map_length_;
   float map_resolution_;
   bool use_confidence_;
-  std::vector<std::string> class_names_{"CAR",     "TRUCK",     "BUS",       "TRAILER",
-                                        "BICYCLE", "MOTORBIKE", "PEDESTRIAN"};
+  std::vector<std::string> class_names_{"UNKNWON", "CAR",     "TRUCK",     "BUS",
+                                        "TRAILER", "BICYCLE", "MOTORBIKE", "PEDESTRIAN"};
   bool rename_car_to_truck_and_bus_;
 
   // Number of width and height cells