feat(lane_change): reduce prepare duration when blinker has been acti…

…vated (autowarefoundation#9185) * add minimum prepare duration parameter Signed-off-by: mohammad alqudah <[email protected]> * reduce prepare duration according to signal activation time Signed-off-by: mohammad alqudah <[email protected]> * chore: update CODEOWNERS (autowarefoundation#9203) Signed-off-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com> Co-authored-by: github-actions <[email protected]> * refactor(time_utils): prefix package and namespace with autoware (autowarefoundation#9173) * refactor(time_utils): prefix package and namespace with autoware Signed-off-by: Esteve Fernandez <[email protected]> * refactor(time_utils): prefix package and namespace with autoware Signed-off-by: Esteve Fernandez <[email protected]> * style(pre-commit): autofix --------- Signed-off-by: Esteve Fernandez <[email protected]> Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com> * feat(rtc_interface): add requested field (autowarefoundation#9202) * add requested feature Signed-off-by: Go Sakayori <[email protected]> * Update planning/autoware_rtc_interface/test/test_rtc_interface.cpp Co-authored-by: Satoshi OTA <[email protected]> --------- Signed-off-by: Go Sakayori <[email protected]> Co-authored-by: Satoshi OTA <[email protected]> * fix(mpc_lateral_controller): correctly resample the MPC trajectory yaws (autowarefoundation#9199) Signed-off-by: Maxime CLEMENT <[email protected]> * fix(bpp): prevent accessing nullopt (autowarefoundation#9204) fix(bpp): calcDistanceToRedTrafficLight null Signed-off-by: Shumpei Wakabayashi <[email protected]> * refactor(autoware_map_based_prediction): split pedestrian and bicycle predictor (autowarefoundation#9201) * refactor: grouping functions Signed-off-by: Taekjin LEE <[email protected]> * refactor: grouping parameters Signed-off-by: Taekjin LEE <[email protected]> * refactor: rename member road_users_history to road_users_history_ Signed-off-by: Taekjin LEE <[email protected]> * refactor: separate util functions Signed-off-by: Taekjin LEE <[email protected]> * refactor: Add predictor_vru.cpp and utils.cpp to map_based_prediction_node Signed-off-by: Taekjin LEE <[email protected]> * refactor: Add explicit template instantiation for removeOldObjectsHistory function Signed-off-by: Taekjin LEE <[email protected]> * refactor: Add tf2_geometry_msgs to data_structure Signed-off-by: Taekjin LEE <[email protected]> * refactor: Remove unused variables and functions in map_based_prediction_node.cpp Signed-off-by: Taekjin LEE <[email protected]> * Update perception/autoware_map_based_prediction/include/map_based_prediction/predictor_vru.hpp * Apply suggestions from code review * style(pre-commit): autofix --------- Signed-off-by: Taekjin LEE <[email protected]> Co-authored-by: Mamoru Sobue <[email protected]> Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com> * refactor(ndt_scan_matcher, ndt_omp): move ndt_omp into ndt_scan_matcher (autowarefoundation#8912) * Moved ndt_omp into ndt_scan_matcher Signed-off-by: Shintaro Sakoda <[email protected]> * Added Copyright Signed-off-by: Shintaro Sakoda <[email protected]> * style(pre-commit): autofix * Fixed include Signed-off-by: Shintaro Sakoda <[email protected]> * Fixed cast style Signed-off-by: Shintaro Sakoda <[email protected]> * Fixed include Signed-off-by: Shintaro Sakoda <[email protected]> * Fixed honorific title Signed-off-by: Shintaro Sakoda <[email protected]> * Fixed honorific title Signed-off-by: Shintaro Sakoda <[email protected]> * style(pre-commit): autofix * Fixed include hierarchy Signed-off-by: Shintaro Sakoda <[email protected]> * style(pre-commit): autofix * Fixed include hierarchy Signed-off-by: Shintaro Sakoda <[email protected]> * style(pre-commit): autofix * Fixed hierarchy Signed-off-by: Shintaro Sakoda <[email protected]> * Fixed NVTP to NVTL Signed-off-by: Shintaro Sakoda <[email protected]> * Added cspell:ignore Signed-off-by: Shintaro Sakoda <[email protected]> * Fixed miss spell Signed-off-by: Shintaro Sakoda <[email protected]> * style(pre-commit): autofix * Fixed include Signed-off-by: Shintaro Sakoda <[email protected]> * Renamed applyFilter Signed-off-by: Shintaro Sakoda <[email protected]> * Moved ***_impl.hpp from include/ to src/ Signed-off-by: Shintaro Sakoda <[email protected]> * style(pre-commit): autofix * Fixed variable scope Signed-off-by: Shintaro Sakoda <[email protected]> * Fixed to pass by reference Signed-off-by: Shintaro Sakoda <[email protected]> --------- Signed-off-by: Shintaro Sakoda <[email protected]> Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com> * feat(autoware_test_utils): add traffic light msgs parser (autowarefoundation#9177) Signed-off-by: Mamoru Sobue <[email protected]> * modify implementation to compute and keep actual prepare duration in transient data Signed-off-by: mohammad alqudah <[email protected]> * if LC path is approved, set prepare duration in transient data from approved path prepare duration Signed-off-by: mohammad alqudah <[email protected]> * change default value of LC param min_prepare_duration Signed-off-by: mohammad alqudah <[email protected]> * Update planning/behavior_path_planner/autoware_behavior_path_lane_change_module/src/utils/utils.cpp Co-authored-by: Zulfaqar Azmi <[email protected]> * add function to set signal activation time, add docstring for function calc_actual_prepare_duration Signed-off-by: mohammad alqudah <[email protected]> * check for zero value max_acc to avoid division by zero Signed-off-by: mohammad alqudah <[email protected]> * chore: rename codeowners file Signed-off-by: tomoya.kimura <[email protected]> * chore: rename codeowners file Signed-off-by: tomoya.kimura <[email protected]> * chore: rename codeowners file Signed-off-by: tomoya.kimura <[email protected]> * allow decelerating in lane changing phase near terminal Signed-off-by: mohammad alqudah <[email protected]> * fix spelling Signed-off-by: mohammad alqudah <[email protected]> * fix units Signed-off-by: mohammad alqudah <[email protected]> * allow decelerating in lane changing phase near terminal Signed-off-by: mohammad alqudah <[email protected]> * Update planning/behavior_path_planner/autoware_behavior_path_lane_change_module/README.md Co-authored-by: Maxime CLEMENT <[email protected]> * run pre-commit check Signed-off-by: mohammad alqudah <[email protected]> * fix spelling Signed-off-by: mohammad alqudah <[email protected]> * fix format Signed-off-by: mohammad alqudah <[email protected]> * allow decelerating in lane changing phase near terminal Signed-off-by: mohammad alqudah <[email protected]> * Update planning/behavior_path_planner/autoware_behavior_path_lane_change_module/README.md Co-authored-by: Maxime CLEMENT <[email protected]> * run pre-commit check Signed-off-by: mohammad alqudah <[email protected]> * fix spelling Signed-off-by: mohammad alqudah <[email protected]> * fix format Signed-off-by: mohammad alqudah <[email protected]> --------- Signed-off-by: mohammad alqudah <[email protected]> Signed-off-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com> Signed-off-by: Esteve Fernandez <[email protected]> Signed-off-by: Go Sakayori <[email protected]> Signed-off-by: Maxime CLEMENT <[email protected]> Signed-off-by: Shumpei Wakabayashi <[email protected]> Signed-off-by: Taekjin LEE <[email protected]> Signed-off-by: Shintaro Sakoda <[email protected]> Signed-off-by: Mamoru Sobue <[email protected]> Signed-off-by: tomoya.kimura <[email protected]> Co-authored-by: awf-autoware-bot[bot] <94889083+awf-autoware-bot[bot]@users.noreply.github.com> Co-authored-by: github-actions <[email protected]> Co-authored-by: Esteve Fernandez <[email protected]> Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com> Co-authored-by: Go Sakayori <[email protected]> Co-authored-by: Satoshi OTA <[email protected]> Co-authored-by: Maxime CLEMENT <[email protected]> Co-authored-by: Shumpei Wakabayashi <[email protected]> Co-authored-by: Taekjin LEE <[email protected]> Co-authored-by: Mamoru Sobue <[email protected]> Co-authored-by: SakodaShintaro <[email protected]> Co-authored-by: Zulfaqar Azmi <[email protected]> Co-authored-by: tomoya.kimura <[email protected]>
a-maumau · Dec 5, 2024 · 0992f1d · 0992f1d
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commit 0992f1d
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diff --git a/.github/CODEOWNERS → .github/_CODEOWNERS b/.github/CODEOWNERS → .github/_CODEOWNERS
diff --git a/planning/behavior_path_planner/autoware_behavior_path_lane_change_module/README.md b/planning/behavior_path_planner/autoware_behavior_path_lane_change_module/README.md
@@ -886,7 +886,8 @@ The following parameters are configurable in [lane_change.param.yaml](https://gi
 | `backward_length_buffer_for_end_of_lane`     | [m]    | double | The end of lane buffer to ensure ego vehicle has enough distance to start lane change                                  | 3.0                |
 | `backward_length_buffer_for_blocking_object` | [m]    | double | The end of lane buffer to ensure ego vehicle has enough distance to start lane change when there is an object in front | 3.0                |
 | `backward_length_from_intersection`          | [m]    | double | Distance threshold from the last intersection to invalidate or cancel the lane change path                             | 5.0                |
-| `trajectory.prepare_duration`                | [m]    | double | The preparation time for the ego vehicle to be ready to perform lane change.                                           | 4.0                |
+| `trajectory.max_prepare_duration`            | [s]    | double | The maximum preparation time for the ego vehicle to be ready to perform lane change.                                   | 4.0                |
+| `trajectory.min_prepare_duration`            | [s]    | double | The minimum preparation time for the ego vehicle to be ready to perform lane change.                                   | 2.0                |
 | `trajectory.lateral_jerk`                    | [m/s3] | double | Lateral jerk value for lane change path generation                                                                     | 0.5                |
 | `trajectory.minimum_lane_changing_velocity`  | [m/s]  | double | Minimum speed during lane changing process.                                                                            | 2.78               |
 | `trajectory.lon_acc_sampling_num`            | [-]    | int    | Number of possible lane-changing trajectories that are being influenced by longitudinal acceleration                   | 3                  |

diff --git a/...vior_path_planner/autoware_behavior_path_lane_change_module/config/lane_change.param.yaml b/...vior_path_planner/autoware_behavior_path_lane_change_module/config/lane_change.param.yaml
@@ -11,7 +11,8 @@
 
       # trajectory generation
       trajectory:
-        prepare_duration: 4.0
+        max_prepare_duration: 4.0
+        min_prepare_duration: 2.0
         lateral_jerk: 0.5
         min_longitudinal_acc: -1.0
         max_longitudinal_acc: 1.0

diff --git a/...avior_path_lane_change_module/include/autoware/behavior_path_lane_change_module/scene.hpp b/...avior_path_lane_change_module/include/autoware/behavior_path_lane_change_module/scene.hpp
@@ -54,7 +54,7 @@ class NormalLaneChange : public LaneChangeBase
 
   void update_lanes(const bool is_approved) final;
 
-  void update_transient_data() final;
+  void update_transient_data(const bool is_approved) final;
 
   void update_filtered_objects() final;
 

diff --git a/...lane_change_module/include/autoware/behavior_path_lane_change_module/utils/base_class.hpp b/...lane_change_module/include/autoware/behavior_path_lane_change_module/utils/base_class.hpp
@@ -68,7 +68,7 @@ class LaneChangeBase
 
   virtual void update_lanes(const bool is_approved) = 0;
 
-  virtual void update_transient_data() = 0;
+  virtual void update_transient_data(const bool is_approved) = 0;
 
   virtual void update_filtered_objects() = 0;
 
@@ -267,6 +267,15 @@ class LaneChangeBase
     return turn_signal;
   }
 
+  void set_signal_activation_time(const bool reset = false) const
+  {
+    if (reset) {
+      signal_activation_time_ = std::nullopt;
+    } else if (!signal_activation_time_) {
+      signal_activation_time_ = clock_.now();
+    }
+  }
+
   LaneChangeStatus status_{};
   PathShifter path_shifter_{};
 
@@ -292,6 +301,7 @@ class LaneChangeBase
 
   mutable StopWatch<std::chrono::milliseconds> stop_watch_;
   mutable lane_change::Debug lane_change_debug_;
+  mutable std::optional<rclcpp::Time> signal_activation_time_{std::nullopt};
 
   rclcpp::Logger logger_ = utils::lane_change::getLogger(getModuleTypeStr());
   mutable rclcpp::Clock clock_{RCL_ROS_TIME};

diff --git a/...ane_change_module/include/autoware/behavior_path_lane_change_module/utils/calculation.hpp b/...ane_change_module/include/autoware/behavior_path_lane_change_module/utils/calculation.hpp
@@ -75,7 +75,7 @@ double calc_dist_to_last_fit_width(
  * of the maximum lane change preparation duration and the maximum velocity of the ego vehicle.
  *
  * @param common_data_ptr Shared pointer to a CommonData structure, which should include:
- *  - `lc_param_ptr->lane_change_prepare_duration`: The duration allowed for lane change
+ *  - `lc_param_ptr->maximum_prepare_duration`: The maximum duration allowed for lane change
  * preparation.
  *  - `bpp_param_ptr->max_vel`: The maximum velocity of the ego vehicle.
  *
@@ -131,6 +131,24 @@ std::vector<double> calc_lon_acceleration_samples(
   const CommonDataPtr & common_data_ptr, const double max_path_velocity,
   const double prepare_duration);
 
+/**
+ * @brief calculates the actual prepare duration that will be used for path generation
+ *
+ * @details computes the required prepare duration to be used for candidate path
+ * generation based on the elapsed time of turn signal activation, the minimum
+ * and maximum parameterized values for the prepare duration,
+ * and the minimum lane changing velocity.
+ *
+ * @param common_data_ptr Shared pointer to a CommonData structure, which includes
+ * lane change parameters and bpp common parameters.
+ * @param current_velocity current ego vehicle velocity.
+ * @param active_signal_duration elapsed time since turn signal activation.
+ * @return The calculated prepare duration value in seconds (s)
+ */
+double calc_actual_prepare_duration(
+  const CommonDataPtr & common_data_ptr, const double current_velocity,
+  const double active_signal_duration);
+
 std::vector<PhaseMetrics> calc_prepare_phase_metrics(
   const CommonDataPtr & common_data_ptr, const double current_velocity,
   const double max_path_velocity, const double min_length_threshold = 0.0,

diff --git a/...ne_change_module/include/autoware/behavior_path_lane_change_module/utils/data_structs.hpp b/...ne_change_module/include/autoware/behavior_path_lane_change_module/utils/data_structs.hpp
@@ -222,6 +222,8 @@ struct TransientData
   size_t current_path_seg_idx;   // index of nearest segment to ego along current path
   double current_path_velocity;  // velocity of the current path at the ego position along the path
 
+  double lane_change_prepare_duration{0.0};
+
   bool is_ego_near_current_terminal_start{false};
   bool is_ego_stuck{false};
 

diff --git a/...lane_change_module/include/autoware/behavior_path_lane_change_module/utils/parameters.hpp b/...lane_change_module/include/autoware/behavior_path_lane_change_module/utils/parameters.hpp
@@ -115,7 +115,8 @@ struct SafetyParameters
 
 struct TrajectoryParameters
 {
-  double prepare_duration{4.0};
+  double max_prepare_duration{4.0};
+  double min_prepare_duration{1.0};
   double lateral_jerk{0.5};
   double min_longitudinal_acc{-1.0};
   double max_longitudinal_acc{1.0};

diff --git a/planning/behavior_path_planner/autoware_behavior_path_lane_change_module/src/interface.cpp b/planning/behavior_path_planner/autoware_behavior_path_lane_change_module/src/interface.cpp
@@ -80,7 +80,7 @@ void LaneChangeInterface::updateData()
   module_type_->setPreviousModuleOutput(getPreviousModuleOutput());
   module_type_->update_lanes(getCurrentStatus() == ModuleStatus::RUNNING);
   module_type_->update_filtered_objects();
-  module_type_->update_transient_data();
+  module_type_->update_transient_data(getCurrentStatus() == ModuleStatus::RUNNING);
   module_type_->updateSpecialData();
 
   if (isWaitingApproval() || module_type_->isAbortState()) {
@@ -155,10 +155,10 @@ BehaviorModuleOutput LaneChangeInterface::plan()
 
 BehaviorModuleOutput LaneChangeInterface::planWaitingApproval()
 {
-  *prev_approved_path_ = getPreviousModuleOutput().path;
-
   BehaviorModuleOutput out = getPreviousModuleOutput();
 
+  *prev_approved_path_ = out.path;
+
   module_type_->insert_stop_point(module_type_->get_current_lanes(), out.path);
   out.turn_signal_info = module_type_->get_current_turn_signal_info();
 
@@ -168,7 +168,7 @@ BehaviorModuleOutput LaneChangeInterface::planWaitingApproval()
     setObjectsOfInterestData(data.current_obj_pose, data.obj_shape, color);
   }
 
-  path_reference_ = std::make_shared<PathWithLaneId>(getPreviousModuleOutput().reference_path);
+  path_reference_ = std::make_shared<PathWithLaneId>(out.reference_path);
   stop_pose_ = module_type_->getStopPose();
 
   if (!module_type_->isValidPath()) {

diff --git a/planning/behavior_path_planner/autoware_behavior_path_lane_change_module/src/manager.cpp b/planning/behavior_path_planner/autoware_behavior_path_lane_change_module/src/manager.cpp
@@ -45,8 +45,10 @@ LCParamPtr LaneChangeModuleManager::set_params(rclcpp::Node * node, const std::s
 
   // trajectory generation
   {
-    p.trajectory.prepare_duration =
-      getOrDeclareParameter<double>(*node, parameter("trajectory.prepare_duration"));
+    p.trajectory.max_prepare_duration =
+      getOrDeclareParameter<double>(*node, parameter("trajectory.max_prepare_duration"));
+    p.trajectory.min_prepare_duration =
+      getOrDeclareParameter<double>(*node, parameter("trajectory.min_prepare_duration"));
     p.trajectory.lateral_jerk =
       getOrDeclareParameter<double>(*node, parameter("trajectory.lateral_jerk"));
     p.trajectory.min_longitudinal_acc =
@@ -67,8 +69,8 @@ LCParamPtr LaneChangeModuleManager::set_params(rclcpp::Node * node, const std::s
       getOrDeclareParameter<int>(*node, parameter("trajectory.lat_acc_sampling_num"));
 
     const auto max_acc = getOrDeclareParameter<double>(*node, "normal.max_acc");
-    p.trajectory.min_lane_changing_velocity =
-      std::min(p.trajectory.min_lane_changing_velocity, max_acc * p.trajectory.prepare_duration);
+    p.trajectory.min_lane_changing_velocity = std::min(
+      p.trajectory.min_lane_changing_velocity, max_acc * p.trajectory.max_prepare_duration);
 
     // validation of trajectory parameters
     if (p.trajectory.lon_acc_sampling_num < 1 || p.trajectory.lat_acc_sampling_num < 1) {
@@ -311,7 +313,10 @@ void LaneChangeModuleManager::updateModuleParams(const std::vector<rclcpp::Param
 
   {
     const std::string ns = "lane_change.trajectory.";
-    updateParam<double>(parameters, ns + "prepare_duration", p->trajectory.prepare_duration);
+    updateParam<double>(
+      parameters, ns + "max_prepare_duration", p->trajectory.max_prepare_duration);
+    updateParam<double>(
+      parameters, ns + "min_prepare_duration", p->trajectory.min_prepare_duration);
     updateParam<double>(parameters, ns + "lateral_jerk", p->trajectory.lateral_jerk);
     updateParam<double>(
       parameters, ns + ".min_lane_changing_velocity", p->trajectory.min_lane_changing_velocity);

diff --git a/planning/behavior_path_planner/autoware_behavior_path_lane_change_module/src/scene.cpp b/planning/behavior_path_planner/autoware_behavior_path_lane_change_module/src/scene.cpp
@@ -131,7 +131,7 @@ void NormalLaneChange::update_lanes(const bool is_approved)
   *common_data_ptr_->lanes_polygon_ptr = create_lanes_polygon(common_data_ptr_);
 }
 
-void NormalLaneChange::update_transient_data()
+void NormalLaneChange::update_transient_data(const bool is_approved)
 {
   if (
     !common_data_ptr_ || !common_data_ptr_->is_data_available() ||
@@ -150,6 +150,13 @@ void NormalLaneChange::update_transient_data()
     prev_module_output_.path.points.at(nearest_seg_idx).point.longitudinal_velocity_mps;
   transient_data.current_path_seg_idx = nearest_seg_idx;
 
+  const auto active_signal_duration =
+    signal_activation_time_ ? (clock_.now() - signal_activation_time_.value()).seconds() : 0.0;
+  transient_data.lane_change_prepare_duration =
+    is_approved ? status_.lane_change_path.info.duration.prepare
+                : calculation::calc_actual_prepare_duration(
+                    common_data_ptr_, common_data_ptr_->get_ego_speed(), active_signal_duration);
+
   std::tie(transient_data.lane_changing_length, transient_data.current_dist_buffer) =
     calculation::calc_lc_length_and_dist_buffer(common_data_ptr_, get_current_lanes());
 
@@ -328,6 +335,8 @@ TurnSignalInfo NormalLaneChange::get_current_turn_signal_info() const
     return get_terminal_turn_signal_info();
   }
 
+  set_signal_activation_time();
+
   return get_turn_signal(getEgoPose(), getLaneChangePath().info.lane_changing_end);
 }
 
@@ -356,9 +365,14 @@ TurnSignalInfo NormalLaneChange::get_terminal_turn_signal_info() const
   const auto nearest_yaw_threshold = common_param.ego_nearest_yaw_threshold;
   const auto current_nearest_seg_idx = common_data_ptr_->transient_data.current_path_seg_idx;
 
-  return getTurnSignalDecider().overwrite_turn_signal(
+  const auto turn_signal_info = getTurnSignalDecider().overwrite_turn_signal(
     path, current_pose, current_nearest_seg_idx, original_turn_signal_info,
     terminal_turn_signal_info, nearest_dist_threshold, nearest_yaw_threshold);
+
+  set_signal_activation_time(
+    turn_signal_info.turn_signal.command != terminal_turn_signal_info.turn_signal.command);
+
+  return turn_signal_info;
 }
 
 LaneChangePath NormalLaneChange::getLaneChangePath() const
@@ -429,8 +443,6 @@ BehaviorModuleOutput NormalLaneChange::generateOutput()
       output.path = utils::combinePath(output.path, *found_extended_path);
     }
     output.reference_path = getReferencePath();
-    output.turn_signal_info =
-      get_turn_signal(getEgoPose(), status_.lane_change_path.info.lane_changing_end);
 
     if (isStopState()) {
       const auto current_velocity = getEgoVelocity();
@@ -446,12 +458,17 @@ BehaviorModuleOutput NormalLaneChange::generateOutput()
 
   extendOutputDrivableArea(output);
 
+  const auto turn_signal_info =
+    get_turn_signal(getEgoPose(), status_.lane_change_path.info.lane_changing_end);
   const auto current_seg_idx = planner_data_->findEgoSegmentIndex(output.path.points);
   output.turn_signal_info = planner_data_->turn_signal_decider.overwrite_turn_signal(
     output.path, getEgoPose(), current_seg_idx, prev_module_output_.turn_signal_info,
-    output.turn_signal_info, planner_data_->parameters.ego_nearest_dist_threshold,
+    turn_signal_info, planner_data_->parameters.ego_nearest_dist_threshold,
     planner_data_->parameters.ego_nearest_yaw_threshold);
 
+  set_signal_activation_time(
+    output.turn_signal_info.turn_signal.command != turn_signal_info.turn_signal.command);
+
   return output;
 }
 

diff --git a/...behavior_path_planner/autoware_behavior_path_lane_change_module/src/utils/calculation.cpp b/...behavior_path_planner/autoware_behavior_path_lane_change_module/src/utils/calculation.cpp
@@ -104,7 +104,7 @@ double calc_dist_to_last_fit_width(
 
 double calc_maximum_prepare_length(const CommonDataPtr & common_data_ptr)
 {
-  const auto max_prepare_duration = common_data_ptr->lc_param_ptr->trajectory.prepare_duration;
+  const auto max_prepare_duration = common_data_ptr->lc_param_ptr->trajectory.max_prepare_duration;
   const auto ego_max_speed = common_data_ptr->bpp_param_ptr->max_vel;
 
   return max_prepare_duration * ego_max_speed;
@@ -197,7 +197,7 @@ std::vector<double> calc_max_lane_change_lengths(
 
   const auto & params = common_data_ptr->lc_param_ptr->trajectory;
   const auto lat_jerk = params.lateral_jerk;
-  const auto t_prepare = params.prepare_duration;
+  const auto t_prepare = params.max_prepare_duration;
   const auto current_velocity = common_data_ptr->get_ego_speed();
   const auto path_velocity = common_data_ptr->transient_data.current_path_velocity;
 
@@ -400,18 +400,41 @@ double calc_lane_changing_acceleration(
     prepare_longitudinal_acc);
 }
 
+double calc_actual_prepare_duration(
+  const CommonDataPtr & common_data_ptr, const double current_velocity,
+  const double active_signal_duration)
+{
+  const auto & params = common_data_ptr->lc_param_ptr->trajectory;
+  const auto min_lc_velocity = params.min_lane_changing_velocity;
+
+  // need to ensure min prep duration is sufficient to reach minimum lane changing velocity
+  const auto min_prepare_duration = std::invoke([&]() -> double {
+    if (current_velocity >= min_lc_velocity) {
+      return params.min_prepare_duration;
+    }
+    const auto max_acc =
+      std::min(common_data_ptr->bpp_param_ptr->max_acc, params.max_longitudinal_acc);
+    if (max_acc < eps) {
+      return params.max_prepare_duration;
+    }
+    return (min_lc_velocity - current_velocity) / max_acc;
+  });
+
+  return std::max(params.max_prepare_duration - active_signal_duration, min_prepare_duration);
+}
+
 std::vector<double> calc_prepare_durations(const CommonDataPtr & common_data_ptr)
 {
   const auto & lc_param_ptr = common_data_ptr->lc_param_ptr;
   const auto threshold = common_data_ptr->bpp_param_ptr->base_link2front +
                          lc_param_ptr->min_length_for_turn_signal_activation;
-  const auto max_prepare_duration = lc_param_ptr->trajectory.prepare_duration;
 
   // TODO(Azu) this check seems to cause scenario failures.
   if (common_data_ptr->transient_data.dist_to_terminal_start >= threshold) {
-    return {max_prepare_duration};
+    return {common_data_ptr->transient_data.lane_change_prepare_duration};
   }
 
+  const auto max_prepare_duration = lc_param_ptr->trajectory.max_prepare_duration;
   std::vector<double> prepare_durations;
   constexpr double step = 0.5;
 

diff --git a/...or_path_planner/autoware_behavior_path_lane_change_module/test/test_lane_change_scene.cpp b/...or_path_planner/autoware_behavior_path_lane_change_module/test/test_lane_change_scene.cpp
@@ -223,7 +223,7 @@ TEST_F(TestNormalLaneChange, testGetPathWhenInvalid)
   constexpr auto is_approved = true;
   normal_lane_change_->update_lanes(!is_approved);
   normal_lane_change_->update_filtered_objects();
-  normal_lane_change_->update_transient_data();
+  normal_lane_change_->update_transient_data(!is_approved);
   normal_lane_change_->updateLaneChangeStatus();
   const auto & lc_status = normal_lane_change_->getLaneChangeStatus();
 
@@ -261,7 +261,7 @@ TEST_F(TestNormalLaneChange, testGetPathWhenValid)
   set_previous_approved_path();
   normal_lane_change_->update_lanes(!is_approved);
   normal_lane_change_->update_filtered_objects();
-  normal_lane_change_->update_transient_data();
+  normal_lane_change_->update_transient_data(!is_approved);
   const auto lane_change_required = normal_lane_change_->isLaneChangeRequired();
 
   ASSERT_TRUE(lane_change_required);