I have not been a fan of the lane assist feature. It has never once actually helped me drive, and it's triggering is entirely false positives. It has been more of a danger than an aid.

I had minor annoyances with it like crossing a dashed line into a newly spawned Interstate exit( who am I going to signal to, the road shoulder?), and having it fight me, or crossing a dashed lines where 2 lanes merge together, and having it fight me

Today it reacted to the shadow line cast by a half concrete wall into the lane and actively started veering me into another lane.

Is there a way to shut off just the lane assist or do I have to shutoff the entire activsense system?

 

I've got a 2022 UK spec Mazda 3 and have managed to turn off the system from one of the menus. It's in the user manual somewhere.

Not sure if it's the same for U.S. spec versions but here's a reference to it in my manual

 

Thanks, that worked

The car steering is no longer reactiving to all kinds of false positives

 

Happy you have got it sorted out.
First time I found it in the settings menus and turned it off I was a bit dissapointed that it came back on the next time I started the car.
Found out you have to have the ignition on whilst changing the setting in order for it to become a persistent change. Guess I should have read the manual a bit more carefully as it does say that, as shown above.