So I just encountered this crash in my MP game:
https://steamuserimages-a.akamaihd.net/ugc/1017192117627775638/C7F2995BF876BE787605509B28DA34B3A3B592EB/
Interestingly enough, nobody was using a hover car at the moment. We don't even have the tech yet. One of my friends was using a normal basegame car though.

This looks like it can just be fixed with some error checking. Was your friend entering or exiting the basegame car at the time of crash? And has this happened any other time while interacting with a basegame car? Thanks.

Edit: While I wasn't able to reproduce anything relating to the error (probably caused from another mod), I have added a nil test statement in version 0.2.7 which should hopefully prevent the crash from happening anymore. Cheers!

Thanks for the quick response and update :) I'll update the mod on our end and if the crash happens again I'll report back here.

I'm getting this same error on version 2.5. Any chance of trapping this error for Factorio 0.17? I got the error when I was first testing the car and it got destroyed while I was in it.

Unfortunately, it is not possible for me to update an old version of the mod to apply the bug fix due to limitations with modding. The only way to fix it is to update your game (and mod) to 0.18.

Scratch that, there may be a way to push an update for the 0.17 version. I will get back to you once I have.

If you are using Factorio 0.17. Please update your mod to version 0.2.9 as this contains the back-ported bugfix. Thank you.

    Version     Game Version
    0.2.9       0.17
    0.2.8       0.18
    0.2.7       0.18

Please don't do that.
Reserve the 0.3.0 for version 0.18 and 0.2.0 for 0.17. There is some lags by this issue.

That would require me to either reupload or remove the 3 - 0.18 versions that I have up, not something that I particularly want to do.

Just set the next 0.18 version to something above 0.3.0.

EDIT: I see the other mod thread. Thank you for posting!

Circling back on this, thank you for creating a fix. Further troubleshooting revealed that the bug caused the game to crash anytime an occupied vehicle was destroyed, regardless of the vanilla or mod origin of the vehicle. Looking at the downloads, it seems that there were problems with the versioning and the fix file has been pulled. Do you have plans to re-post it? It seems the recommendation was to wait for an 0.18 update to be needed so you can post 0.17 as 0.2.9 and 0.18 as 0.3.0.