diff --git a/modules/prediction/common/prediction_gflags.cc b/modules/prediction/common/prediction_gflags.cc
index d69d9e30348a065b8f6cb1d6aa11908c1d442f68..fd0ec5237263ae384b616df2057fa4e05757480c 100644
--- a/modules/prediction/common/prediction_gflags.cc
+++ b/modules/prediction/common/prediction_gflags.cc
@@ -62,6 +62,8 @@ DEFINE_bool(enable_all_junction, false,
             "If consider all junction with junction_mlp_model.");
 DEFINE_double(caution_search_distance_ahead, 50.0,
               "The distance ahead to search caution-level obstacles");
+DEFINE_double(caution_search_distance_backward, 50.0,
+              "The distance backward to search caution-level obstacles");
 DEFINE_double(caution_search_distance_backward_for_merge, 60.0,
               "The distance backward to search caution-lebel obstacles "
               "in the case of merging");
diff --git a/modules/prediction/common/prediction_gflags.h b/modules/prediction/common/prediction_gflags.h
index e4ea01340469af48dbfad55f787e1f39093ce937..ce846716d2103b6647cbf16fcf77001d940a7dbc 100644
--- a/modules/prediction/common/prediction_gflags.h
+++ b/modules/prediction/common/prediction_gflags.h
@@ -46,6 +46,7 @@ DECLARE_int32(road_graph_max_search_horizon);
 DECLARE_double(junction_distance_threshold);
 DECLARE_bool(enable_all_junction);
 DECLARE_double(caution_search_distance_ahead);
+DECLARE_double(caution_search_distance_backward);
 DECLARE_double(caution_search_distance_backward_for_merge);
 DECLARE_double(caution_search_distance_backward_for_overlap);
 DECLARE_double(caution_pedestrian_approach_time);
diff --git a/modules/prediction/scenario/prioritization/obstacles_prioritizer.cc b/modules/prediction/scenario/prioritization/obstacles_prioritizer.cc
index 8da6cc8d099602268dbae3c938a57936bcbae837..79c4eba1cc0ada268fd8d45cc00c1d2864c7c09b 100644
--- a/modules/prediction/scenario/prioritization/obstacles_prioritizer.cc
+++ b/modules/prediction/scenario/prioritization/obstacles_prioritizer.cc
@@ -59,7 +59,8 @@ int NearestFrontObstacleIdOnLaneSequence(const LaneSequence& lane_sequence) {
   int nearest_front_obstacle_id = std::numeric_limits<int>::min();
   double smallest_relative_s = std::numeric_limits<double>::max();
   for (const auto& nearby_obs : lane_sequence.nearby_obstacle()) {
-    if (nearby_obs.s() < 0.0) {
+    if (nearby_obs.s() < 0.0 ||
+        nearby_obs.s() > FLAGS_caution_search_distance_ahead) {
       continue;
     }
     if (nearby_obs.s() < smallest_relative_s) {
@@ -74,7 +75,8 @@ int NearestBackwardObstacleIdOnLaneSequence(const LaneSequence& lane_sequence) {
   int nearest_backward_obstacle_id = std::numeric_limits<int>::min();
   double smallest_relative_s = std::numeric_limits<double>::max();
   for (const auto& nearby_obs : lane_sequence.nearby_obstacle()) {
-    if (nearby_obs.s() > 0.0) {
+    if (nearby_obs.s() > 0.0 ||
+        nearby_obs.s() < -FLAGS_caution_search_distance_backward) {
       continue;
     }
     if (-nearby_obs.s() < smallest_relative_s) {