Yesterday I was driving my 2018 Model 3 with TACC engaged while driving through a highway interchange (one highway was ending and merging onto another), when out of nowhere my set speed suddenly jumped from ~62mph up to 90mph and the car started aggressively accelerating up towards 90mph.
Right before this occurred, I was using the right scroll wheel to very slowly increase my set speed up from 60 to 65mph — bumping it up by 1mph every couple seconds or so — but I only made it to 62mph (or so) before it jumped to 90mph. I definitely did not do a “quick” scroll wheel roll that would cause the set speed to increase by 5mph, nor did I touch the stalk or the accelerator pedal. And I have the set speed programmed in my car to engage at the current speed, not an offset from the speed limit. In the minutes prior, I was either using AP or TACC to maintain a speed right around 60mph.
This wasn’t the first time that I've had the TACC/AP set speed suddenly jump way up on me, but this was the first time I made a point of remembering all of the relevant details to post about later. Overall, I’d guess that this has happened to me 3-5 times over the past 6 months or so. And I think that in each prior instance the set speed has similarly jumped by ~30mph, but I’m from from certain about this detail.
I found this behavior pretty alarming and potentially dangerous, so I wanted to post and see if anyone else has experienced behavior like this in their car?
And/Or does anyone have an explanation or good theory about what might have happened here?
Other possibly relevant details…
Right before this occurred, I was using the right scroll wheel to very slowly increase my set speed up from 60 to 65mph — bumping it up by 1mph every couple seconds or so — but I only made it to 62mph (or so) before it jumped to 90mph. I definitely did not do a “quick” scroll wheel roll that would cause the set speed to increase by 5mph, nor did I touch the stalk or the accelerator pedal. And I have the set speed programmed in my car to engage at the current speed, not an offset from the speed limit. In the minutes prior, I was either using AP or TACC to maintain a speed right around 60mph.
This wasn’t the first time that I've had the TACC/AP set speed suddenly jump way up on me, but this was the first time I made a point of remembering all of the relevant details to post about later. Overall, I’d guess that this has happened to me 3-5 times over the past 6 months or so. And I think that in each prior instance the set speed has similarly jumped by ~30mph, but I’m from from certain about this detail.
I found this behavior pretty alarming and potentially dangerous, so I wanted to post and see if anyone else has experienced behavior like this in their car?
And/Or does anyone have an explanation or good theory about what might have happened here?
Other possibly relevant details…
- "Cruise Set Speed" setting: Current speed. (Not "speed limit".)
- FSD enabled?: Yes
- H/w version: HW3
- S/w version: 2021.4.18
- Location: Eastbound IL-56 merging into I-88 near Sugar Grove, IL.
- Speed limits: IL-56 is 55mph and I-88 is 65mph, but there was a 60mph construction-zone speed limit sign on the interchange ramp.
- Lead vehicle?: There was no one in front of me.
- Sharp curves?: There are no sharp curves along this route. (See map screenshot below.)