Missing drivable area when two lanelets merged into one

[felixf4xu]

Checklist

• I've read the contribution guidelines.
• I've searched other issues and no duplicate issues were found.
• I'm convinced that this is not my fault but a bug.

Description

I have a map where 2 lanes will merge into one, like this:

and it can be simplified as this:

Expected behavior

on dashed lines, lane change should be possible, all area should be drivable.

Actual behavior

There is some triangle area (circle in red), which is not drivable

Steps to reproduce

the lanelet map is uploaded
lanelet2_map.zip

Versions

• Ubuntu 22
• Humble
• autoware main branch

Possible causes

in the overlapped area, it's difficult to tell which lanelets are neighbors

Additional context

No response

[felixf4xu]

First of all, I would like to check if the map (lanelet) is drawn correctly, I mean, maybe there are some other ways to draw the lanelets so that autoware can successfully understand.

[mehmetdogru]

Thank you @felixf4xu for creating the issue.

The map seems right to me.

For path planner to expand drivable area so that neighbor lanes as well would be covered, they should share a linestring at the moment. Since in your drawings lanelet 2 and 3 does not share a linesting drivable area is not expanded. I am not sure how easy to implement what you want.

[felixf4xu]

That missing triangle area actually does not matter much when driving at 4-2-1 or 5-3-1, but it matters when checking if lane change is possible from 4 -> 5 or from 5 -> 4.

[maxime-clem]

The map is fine but the current planning modules do not handle this case well.
To do the lane change with a merging lane, it is better to draw lanelet 2 as a triangle such that it does not have a successor but has an adjacent lanelet (required to do lane change).

I tested it and now we can do a lane change.

I could not find anything about merging lanes in the map creation requirements (https://docs.pilot.auto/en/reference-design/common/map-requirements/overview) so we should probably keep this issue open and either:

• Add a requirement for merging lanes in the documentation.
• Properly handle merging lanes represented with 2 lanelets preceding one lanelet.

[stale]

This pull request has been automatically marked as stale because it has not had recent activity.

[felixf4xu]

I tested it and now we can do a lane change

Hi @maxime-clem , did you test it with some new code added? is the code already merged into some branch of autoware.universe?

[maxime-clem]

did you test it with some new code added?

No new code. I only modified the map file as I described.