Update based on feedback

Signed-off-by: Zulfaqar Azmi <[email protected]>

planning/behavior_path_planner/README.md

@@ -107,9 +107,9 @@ The Planner Manager's responsibilities include:
 | :---------------------------- | :------------------------------------------------------- | :--------------------------------------------------------------------------------------------- | ----------------- |
 | ~/output/path                 | `autoware_auto_planning_msgs::msg::PathWithLaneId`       | the path generated by modules.                                                                 | `volatile`        |
 | ~/output/turn_indicators_cmd  | `autoware_auto_vehicle_msgs::msg::TurnIndicatorsCommand` | turn indicators command.                                                                       | `volatile`        |
-| ~/output/hazard_lights_cmd    | `tier4_planning_msgs::msg::PathChangeModuleArray`        | hazard lights command.                                                                         | `volatile`        |
+| ~/output/hazard_lights_cmd    | `autoware_auto_vehicle_msgs::msg::HazardLightsCommand`   | hazard lights command.                                                                         | `volatile`        |
 | ~/output/modified_goal        | `autoware_planning_msgs::msg::PoseWithUuidStamped`       | output modified goal commands.                                                                 | `transient_local` |
-| ~/output/stop_reasons         | `tier4_planning_msgs::msg::StopReasonArray`              | output modified goal commands.                                                                 | `volatile`        |
+| ~/output/stop_reasons         | `tier4_planning_msgs::msg::StopReasonArray`              | describe the reason for ego vehicle stop                                                       | `volatile`        |
 | ~/output/reroute_availability | `tier4_planning_msgs::msg::RerouteAvailability`          | the path the module is about to take. to be executed as soon as external approval is obtained. | `volatile`        |
 
 ### Debug
@@ -147,6 +147,22 @@ corresponds to launch_avoidance_module from `default_preset.yaml`.
 
 Therefore, to enable or disable a module, simply set the corresponding module in `default_preset.yaml` to `true` or `false`. These changes will be applied upon the next launch of Autoware.
 
+## Generating Path
+
+A sophisticated methodology is used for path generation, particularly focusing on maneuvers like lane changes and avoidance. At the core of this design is the smooth lateral shifting of the reference path, achieved through a constant-jerk profile. This approach ensures a consistent rate of change in acceleration, facilitating smooth transitions and minimizing abrupt changes in lateral dynamics, crucial for passenger comfort and safety.
+
+The design involves complex mathematical formulations for calculating the lateral shift of the vehicle's path over time. These calculations include determining lateral displacement, velocity, and acceleration, while considering the vehicle's lateral acceleration and velocity limits. This is essential for ensuring that the vehicle's movements remain safe and manageable.
+
+The `ShiftLine` struct (see [here](https://github.com/autowarefoundation/autoware.universe/blob/9000f430c937764c14e43109539302f1f878ed70/planning/behavior_path_planner/include/behavior_path_planner/utils/path_shifter/path_shifter.hpp#L35-L48) for the actual data structure) is utilized to represent points along the path where the lateral shift starts and ends. It includes details like the start and end points in absolute coordinates, the relative shift lengths at these points compared to the reference path, and the associated indexes on the reference path. This struct is integral to managing the path shifts, as it allows the path planner to dynamically adjust the trajectory based on the vehicle's current position and planned maneuver.
+
+Furthermore, the design and its implementation incorporate various equations and mathematical models to calculate essential parameters for the path shift. These include the total distance of lateral shift, the maximum allowable lateral acceleration and jerk, and the total time required for the shift. Practical considerations are also noted, such as simplifying assumptions in the absence of a specific time interval for most lane change and avoidance cases.
+
+The shifted path generation logic allows behavior path planner to dynamically generate safe and efficient paths, precisely controlling the vehicle’s lateral movements to ensure smooth execution of lane changes and avoidance maneuvers. This careful planning and execution adhere to the vehicle's dynamic capabilities and safety constraints, maximizing efficiency and safety in autonomous vehicle navigation.
+
+!!! note
+
+    If you're a math lover, refer to [Path Generation Design](./docs/behavior_path_planner_path_generation_design.md) for the nitty-gritty.
+
 ## Collision Assessment / Safety check
 
 The collision assessment function's purpose in the Behavior Path Planner is to evaluate the potential for collisions with target objects across all modules. It is utilized in two scenarios. The first event occurs during candidate path generation to ensure that the generated candidate path is collision-free. The second occurs when the path is approved by the manager, and the ego vehicle is executing the current module. If the current situation is unsafe, depending on each module's requirements, the planner will either cancel the execution or opt to execute another module.
@@ -206,22 +222,6 @@ The `TurnIndicatorsCommand` message structure has a command field that can take
 
     For more in-depth information, refer to [Turn Signal Design](./docs/behavior_path_planner_turn_signal_design.md) document.
 
-## Generating Shifted Path
-
-A sophisticated methodology is used for path generation, particularly focusing on maneuvers like lane changes and avoidance. At the core of this design is the smooth lateral shifting of the reference path, achieved through a constant-jerk profile. This approach ensures a consistent rate of change in acceleration, facilitating smooth transitions and minimizing abrupt changes in lateral dynamics, crucial for passenger comfort and safety.
-
-The design involves complex mathematical formulations for calculating the lateral shift of the vehicle's path over time. These calculations include determining lateral displacement, velocity, and acceleration, while considering the vehicle's lateral acceleration and velocity limits. This is essential for ensuring that the vehicle's movements remain safe and manageable.
-
-The `ShiftLine` struct (see [here](https://github.com/autowarefoundation/autoware.universe/blob/9000f430c937764c14e43109539302f1f878ed70/planning/behavior_path_planner/include/behavior_path_planner/utils/path_shifter/path_shifter.hpp#L35-L48) for the actual data structure) is utilized to represent points along the path where the lateral shift starts and ends. It includes details like the start and end points in absolute coordinates, the relative shift lengths at these points compared to the reference path, and the associated indexes on the reference path. This struct is integral to managing the path shifts, as it allows the path planner to dynamically adjust the trajectory based on the vehicle's current position and planned maneuver.
-
-Furthermore, the design and its implementation incorporate various equations and mathematical models to calculate essential parameters for the path shift. These include the total distance of lateral shift, the maximum allowable lateral acceleration and jerk, and the total time required for the shift. Practical considerations are also noted, such as simplifying assumptions in the absence of a specific time interval for most lane change and avoidance cases.
-
-The shifted path generation logic allows behavior path planner to dynamically generate safe and efficient paths, precisely controlling the vehicle’s lateral movements to ensure smooth execution of lane changes and avoidance maneuvers. This careful planning and execution adhere to the vehicle's dynamic capabilities and safety constraints, maximizing efficiency and safety in autonomous vehicle navigation.
-
-!!! note
-
-    If you're a math lover, refer to [Path Generation Design](./docs/behavior_path_planner_path_generation_design.md) for the nitty-gritty.
-
 ## Parameters and Configuration
 
 The [configuration files](https://github.com/autowarefoundation/autoware_launch/tree/main/autoware_launch/config/planning/scenario_planning/lane_driving/behavior_planning/behavior_path_planner) are organized in a hierarchical directory structure for ease of navigation and management. Each subdirectory contains specific configuration files relevant to its module. The root directory holds general configuration files that apply to the overall behavior of the planner. The following is an overview of the directory structure with the respective configuration files.
@@ -265,5 +265,6 @@ preset
 
 ## Limitations & Future Work
 
-1. Some module cannot be simultaneously executed for now. For instance
-   - Avoidance and Goal planner
+1. Goal Planner module cannot be simultaneously executed together with other modules.
+2. Module is not designed as plugin. Integrating custom module is not straightforward and user have to modify some part of the behavior path planner main code.
+3.