Model 3

New FSD Seems Too Fast on Freeway Interchanges

Late 2020 3 LR ... I just purchased FSD yesterday and took it for its maiden voyage this morning. While driving NOA on two major interstates, the car did not slow down at all on the interchange ramp between the two. It attempted to navigate the single-lane ramp at 65 mph. The advisory speed is indicated for 35 and I usually take it comfortably at 45. I finally cancelled NOA and took over as it was just too aggressive. I am wondering if this is normal, or whether it will improve over time as the car "learns".

I did search for this issue on the forum as well as Google and it did not return much specific to the issue, so I am hoping it's not a widespread known issue. The car only had about 7 miles of NOA when this occurred.


  • I've found it drops speed on the freeway to freeway interchanges, but it likely depends on a lot of variables, including speed signs and internal map data of curves.

    The entire software has been rewritten and is just rolling out to early access customers now. If all goes to plan, it should roll out to everyone else at the end of the year. So I wouldn't be too concerned about what it does today, as it is running on the prior generation of software. Remember, you are still in charge and responsible, so take over if needed.
  • For now, you can flick the right scroll wheel down as far as needed to drop the cars speed while remaining in NOA
  • That’s how I feel about the speed at which the car takes turns on the highway and I flick down the speed until I feel comfortable.
  • Can't you just roll down the max speed with NOA on and then back up when you want it higher?
  • Depends how it’s mapped to the location. The new beta FSD seems more intuitive than absolute.
  • I think it slows sown way too much and am constantly using the throttle to increase speed.

    Then again in my younger days I would take the ramps at twice the recommended speed now I'm happy if I don't have to slow down from the normal speed limit.
  • I just realized you are from Vegas maybe the car learned the ramps from me taking them at speed :)
  • > @kaffine_98030666 said:
    > I just realized you are from Vegas maybe the car learned the ramps from me taking them at speed :)

    Hmmm ... seems plausible! LOL
  • kaffine_98030666 - It's the ramp from 15-S to 215-W that wowed me this morning.
  • Not widespread. I rarely feel fsd goes too fast. Usually opposite IME. Rewrite will change everything. Wouldn’t worry about eccentricities of this version (will have a whole new level of complexity to explore soon).
  • I agree with you, it's way to aggressive on off ramps.
  • Has only happened for me on a couple in our metro area. Most of our ramps handles just fine
  • I get quite the opposite on off ramps...slows down a bit too fast for my, it is slowing to the correct speed but it happens too fast...but boy, what a fantastic car!
  • I'm with @NorthValley on this one. It's been stated before around here (don't know what Tesla's official line is) that the mapping/speed limit software gets the average speed of users going through an interstate-to-interstate connection and uses that. That seems to be right, because it appears that the speed limit during rush hour is often stuck into that average. In the dead of night when there's no traffic about, and one can take the interchange, comfortably, at, say, 45 mph, the car will slow to 35 mph. Not because it's a steep turn; it's just that during most of the day, people go slower because of congestion.
    On the other hand, during times of congestion, the radar is slowing the car down below that average because of cars in front, so one doesn't notice that the speed limit is also restricted.
    Suggest that if the car's going too fast 'round the turns, hit the right wheel on the steering wheel and file a bug report. FWIW, there used to be a left exit on I-78 in NJ that the navigation software got completely wrong; I filed a bunch of bug reports; whether that was me or not, the car now goes through that intersection properly, starting about five months or so ago.
  • I tried 2020.40.8 for the first time yesterday and found it to be a little faster than I'd like for conditions (it had rained heavily during the night, and was still a little drizzly off and on), so I ultimately cancelled it, but it was certainly much better than some of the past versions at handling the often confusing ATL navigation. I'm not putting much into it given the full re-write rollout soon, though.
  • Thanks for all the answers, everyone! If it’s mapping by driver data that may be right. It was Sunday morning so traffic was generally light. Unfortunately, the ramp I was preparing to merge into had much heavier traffic, so barreling in at 65 or near 65 would have been suboptimal at best.

    I join the chorus looking forward to the imminent rewrite rollout. I’m betting it will be quite a leap forward. That’s why I went ahead and invested the $8k, rather than $10k later this week.
  • Am I the only one who doesn’t use FSD in rainy conditions? Am I being too careful?
  • @larry_98733015
    Generally any form of cruise control is frowned upon on slick roads. If there is standing water, there's a hydroplaning risk. So it's a judgment call. I find that the cameras can see the lane markers better than I can at night in the rain, so I tend to use EAP if the road conditions seem safe.
  • @larry_98733015 - I don't use it in heavy rain, but it wasn't even enough when I was driving to turn on the wipers. Just a few spots where it was still spritzing, and there were wet patches, but not fully wet roads.
  • > @hokiegir1 said:
    > @larry_98733015 - I don't use it in heavy rain, but it wasn't even enough when I was driving to turn on the wipers. Just a few spots where it was still spritzing, and there were wet patches, but not fully wet roads.

    Glad to hear. Be careful out there. I take back control on slick roads and when I hit grooved pavement. I hate grooved pavement.

    I’m kind of amazed at all of the old wrecks I drove that somehow didn’t manage to kill me and I have gotten sideways in some of them on an off ramp in a rainstorm. I have no nostalgia for any old car, lol, certainly nothing built in the 60s, 70s, 80, 90s, well, you get the idea.

    I don’t want to see anybody hurt by the autonomous driving system.
  • If the rain is heavy enough to obscure its camera vision it will disable itself. It seems pretty conservative there. If you’re just talking lane keeping anyway... wouldn’t try it in city streets.
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