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Limits speed to 45 mph when unknown speed limit

tigerrr

Member
May 19, 2018
22
6
Zeeland, MI
In Michigan "In Michigan, the speed limit on unmarked roads is 25 mph in residential areas and 55 mph on trunk line and county highways. However, on other roads, if there is no properly posted speed limit sign, the “basic speed law” applies which requires a careful, prudent, reasonable and proper speed." HOWEVER my Model 3 will only go 45 mph on the surface streets if it doesn't know the speed limit. Sigh, it annoys others on the road and I normally turn AP off if there is someone behind me. Does anyone know if V9 FSD knows default speed limits in states or will it still limit speed to 45? FSD pretty much useless on surface streets outside of city if so. And if there is no end of limit sign the car will eventually slow down if a long way from the last 55 speed limit sign.
 

tigerrr

Member
May 19, 2018
22
6
Zeeland, MI
I just looked up California "Unless otherwise posted, the maximum speed limit is 55 mph on two-lane undivided highways and for vehicles towing trailers." Have California peeps noticed the 45 mph limit on surface streets?
 

TresLA

Member
Jul 15, 2018
205
239
L.A.
I’m in California. I don‘t have FSD beta, but do have normal AP & purchased “FSD capability” included features. I engage AP most everywhere I can.

I have never noticed a 45 MPH limit, but then again maybe the speed limit is known (navigation data) for all the roads I activate AP on.

It doesn’t allow you to up the set speed past 45 on those streets?
 

hellobye

Member
Apr 14, 2021
85
67
Indiana
In Indiana, our state has the 55 rule. In our neighborhood, there is a posted speed limit of 20, but sometimes the vehicle shows it as 45 if I have not gotten to it yet, which is terrifying. This is the only instance I have noticed it.
 

tigerrr

Member
May 19, 2018
22
6
Zeeland, MI
I’m in California. I don‘t have FSD beta, but do have normal AP & purchased “FSD capability” included features. I engage AP most everywhere I can.

I have never noticed a 45 MPH limit, but then again maybe the speed limit is known (navigation data) for all the roads I activate AP on.

It doesn’t allow you to up the set speed past 45 on those streets?
True Max speed for AP is not allowed above 45 on those streets / (lane keeping and speed control & stop sign/light features and not in the beta program). I thought maybe Tesla doesn't know how much a problem that is because, you know, California and city is most of their experience/testing/market?
 

TresLA

Member
Jul 15, 2018
205
239
L.A.
Perhaps people reporting speed limit issues helps? Not sure, as I know driving near Tesla HQ there is a freeway exit ramp that NoAP still takes way too fast (I wait until the last moment before taking over just to see if they've fixed it). There are also still plenty of roads in Southern and Northern California with the wrong speed limit for at least a stretch, where I have to press the accelerator or spin the scroll wheel down to reduce the speed. Anyhow, point being the Navigation data isn't complete and speed limit signs aren't always visible in time.
 

EVRider-FL

Active Member
Aug 18, 2015
1,036
584
South Florida
The 45mph limit is documented in the manual:

In situations where the speed limit cannot be detected when Autosteer is engaged, Autosteer reduces your driving speed and limits the set cruising speed to 45 mph (70 km/h). Although you can manually accelerate to exceed the limited speed, Model 3 may not brake for detected obstacles. Autosteer slows down to the limited speed when you release the accelerator pedal. When you leave the road, or disengage Autosteer by using the steering wheel, you can increase your set speed again, if desired.
 
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Mr. Michael

Member
Oct 2, 2019
95
99
Wisconsin
We have the same speed limit rules in Wisconsin. I would say that the car doesn’t know the speed limit, or thinks it does and it is incorrect on at least a third of the rural highways. It will set the speed at 35 miles/hr for long (10 - 20 miles) stretches, where the road is straight and has a 55 mph unposted limit. This isn’t just one location - many. In a couple cases it had been correct, and the last nav map update made it worse. There appears to be no recourse. Tesla really needs to pay attention to a method to fix this, or it is a hard feature to recommend. Let the driver override the nonsense map data.
 
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techlogik

Closed
Mar 22, 2021
380
279
FL
Key word is while on Autosteer. This isn't being applied to ACC right? Currently autosteer is limited to +5mph of posted limit in certain areas I've noticed...yet some things, like HWY, it will go up to 85 mph limit set. Haven't personally been on an unmarked road that wasn't under county/city control that proper speed signs aren't in place it is using to determine the speed +5 on autosteer. How it applies ACC I would be curious to see video.

Do you have an example/video of it doing this un an unmarked speed portion of a road where it won't go above 45mph? Since it is recording the last hour of all driving, this should be easy to get and chop down to a short video.

Thx
 

techlogik

Closed
Mar 22, 2021
380
279
FL
^Replying to above, I happened to go down a road today of all things per TS, no posted limit. So I tested the 45mph cruise control/ACC/Autopilot, sure enough, it limits it to 45mph.

That should not be a thing.

Aren't there in some places in Montana and around the Country where there are no speed limits on highways...wouldn't that mean you would be stuck at 45mph on Autopilot then?

Yeah...the road was narrow and twisty, so fine and I wouldn't have used Autopilot anyway in this scenario...but it is limited for sure.
 

avs007

Member
May 14, 2021
514
372
PacNW
I wonder how it reacts with variable speed limits... There are sections of the freeway around here, where each lane has a different speed limit... (Crazy, I know).. There were times when the right two lanes have a 35mph limit, and the left lane has a 60 mph limit.
 

Knightshade

Well-Known Member
Jul 31, 2017
13,673
23,267
NC
^Replying to above, I happened to go down a road today of all things per TS, no posted limit. So I tested the 45mph cruise control/ACC/Autopilot, sure enough, it limits it to 45mph.

That should not be a thing.

The manual explicitly tells you autosteer is not intended to be used at all on those roads.

And then tells you if you insist on doing it anyway, you get to deal with the speed limitations documented in the manual.


Aren't there in some places in Montana and around the Country where there are no speed limits on highways

Nope.

Also this doesn't apply to actual limited access/divided highways. On those you can go any speed you want on Autosteer up to the max the system can handle, which is 90, no matter what the speed limit is.

Because those are the roads AS is currently intended for use on.
 

Knightshade

Well-Known Member
Jul 31, 2017
13,673
23,267
NC
Man, if everyone went along with that Tesla would have zero data for secondary roads.



Of course they would.

Data collection doesn't require AP be engaged.

It doesn't even require the car to have AP (remember even basic AP was optional until early 2019).

The cameras and computer collect data and execute campaigns just fine in 100% manual drive mode too.
 

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