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Unexpected autopilot speed increase

I have already called Tesla today and they want me to submit a bug report when this error happens.
This issue always happens in one exact spot on a highway I travel about once per week.
I have a 2018 model 3 with the advanced autopilot option.
When I travel east on Route 80 in New Jersey and take exit 47A which is a left 2 lane exit on to another highway route 280. The navigate on autopilot takes the exit perfectly. I usually have the speed set around 75 when on route 80 but lower the speed when entering this exit to around 62. I travel over 1/4 mile at 62 MPH and then the car accelerates rather quickly up to 75MPH with no input from me. The first couple of times it happened I wasn't sure if I hit the right scroll wheel but after it happened a few times I took great care last night in observing this behavior.
I will not be on this road again till next Thursday or Friday to submit the bug.
 

ATPMSD

Active Member
Mar 12, 2021
1,322
1,209
Atlanta, GA
I do not agree that AP should accelerate

With navigate engaged, the car moves into the exit lane and then slows down as it transitions from one highway to another, depending on the curve. Then after entering the new highway it speeds up; that is by design. Also check your speed offset setting under the Autopilot menu.
 
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I will check what the speed limit indication is next time. I do not agree that AP should accelerate if I have set a speed that is below the speed limit. AP also speeds up to a higher speed then posted. Posted speed limit was 65 and the car went to 73 last night.
That definitely sounds like a bug that you should report when you next drive that stretch of road. AP/FSD changes the speed to match the speed limit for me (I have 0 offsets), up or down. But it's never gone over the speed limit unless I've manually adjusted the speed myself using the wheel.
 
I traveled this route with the same issue. The posted speed limit is 65 including the exit witch is a 2 lane left side exit. Speed sign in car shows it is 65MPH the entire way.
This time I was on Autopilot going 75MPH on route 80 east then I manually slowed the car to 64MPH using the right scroll wheel just before the exit starts still on Autopilot. About 1/2 mile later after being fully on route 280 east the car accelerated to 75.
 
With navigate engaged, the car moves into the exit lane and then slows down as it transitions from one highway to another, depending on the curve. Then after entering the new highway it speeds up; that is by design. Also check your speed offset setting under the Autopilot menu.
The car does not slow down when taking this exit which is a 2 lane 65MPH exit. I manually use the right scroll wheel to slow the car. The car should not speed up after that point.
 

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