[proposal] define new regulatory element SubType:crosswalk

[satoshi-ota]

We TIER IV would like to propose crosswalk regulatory element.

background

In the map used by autoware, the crosswalks are represented using lanelet::Lanelet, and tie the stop_line by regulatory element road_marking. On the other hand, there is no relation between road and crosswalk on lanelet2_map.osm file.

Therefore, the route graph is used to judge whether the behavior_velocity_planner launch crosswalk scene module in autoware. The route graph is built when the lanelet map is loaded, and has data on which crosswalk intersects with ego's route.

void CrosswalkModuleManager::launchNewModules(const PathWithLaneId & path)
{
  const auto rh = planner_data_->route_handler_;
  for (const auto & crosswalk : getCrosswalksOnPath(
         planner_data_->current_pose.pose, path, rh->getLaneletMapPtr(),
         rh->getOverallGraphPtr())) {
    const auto module_id = crosswalk.id();
    if (!isModuleRegistered(module_id)) {
      registerModule(std::make_shared<CrosswalkModule>(
        module_id, crosswalk, crosswalk_planner_param_, logger_.get_child("crosswalk_module"),
        clock_));
      ...
    }
  }
}

https://github.com/autowarefoundation/autoware.universe/blob/7e37a6c65a6a72ddf537ac673bf76cd3ff7ae581/planning/behavior_velocity_planner/src/scene_module/crosswalk/manager.cpp#L126-L142

However, even if Lanelet A and Lanelet B is not overlap each other in 3D, the route graph judges that they are conflicting in 2D.

So the crosswalk module may be activated for crosswalks that do not exist on the ego path in environments where roads are intersecting three dimentionaly each other as shown below, and we would like to solve this problem.

proposal new regulatory element for crosswalk

We would like to indicate which road lanelets related to the crosswalk explicitly by proposed crosswalk regulatory element.

pros

• can find correct crosswalk which related to ego behavior in 3D environment
• easier to tie object (e.g. linestring, polygon, area, etc...) other than lanelet

cons

• autoware will not work properly in old format maps
• increase map maintenance costs

As a countermeasure for this these cons, we TIER IV are discussing the following ideas:

• add feature to Vector Map Builder, which validates lanelet map and output a warning if crosswalk regulatory element is not defined correctly
• develop tools to create crosswalk regulatory element automaticaly

[satoshi-ota]

@yukkysaito @mitsudome-r @xmfcx

[mitsudome-r]

Thanks for the proposal. I think @yukkysaito and I are aligned on this.

[xmfcx]

@satoshi-ota thanks for preparing this improvement proposal.

I need some clarifications on what will change, it's not clear to me from the images.

• How will a lanelet refer to a crosswalk regulatory element?
• How do you refer to multiple StopLines from the crosswalk regulatory element?

[satoshi-ota]

@xmfcx Thanks for comments 😄

How will a lanelet refer to a crosswalk regulatory element?

If there is a crosswalk on the road, I am going to set the ID of the crosswalk regulatory element in the road lanelet as follows.

  <relation id="1">
    ...
    <--! refer the crosswalk regulatory element -->
    <member type="relation" role="regulatory_element" ref="4"/>
    <tag k="type" v="lanelet"/>
    <tag k="subtype" v="road"/>
    ...
  </relation>

How do you refer to multiple StopLines from the crosswalk regulatory element?

I am going to set the ID's of StopLine in the crosswalk regulatory element as follow.

  <relation id="190343">
    ...
    <--! refer the crosswalk lanelet -->
    <member type='way' ref='2' role='refers' />
    <--! refer the stop line linestrings -->
    <member type="way" role="ref_line" ref="3"/> 
    <member type="way" role="ref_line" ref="5"/>
    <tag k="type" v="regulatory_element"/>
    <tag k="subtype" v="crosswalk"/>
    ...
  </relation>

[xmfcx]

@satoshi-ota thanks for the explanations. They are now clear to me. I support this proposal.

[satoshi-ota]

@xmfcx Thank you, too. I'll keep you posted. 😄

[mitsudome-r]

@satoshi-ota We have discussed this in ASWG as well. There were no opposition, and I think we can move forward with implementation of new crosswalk format.