The dangers of TACC with Speed Assist

[Knightshade]

In the States there are time-of-day speed restrictions around schools, and the driver has to manually reduce the maximum speed, sometimes by 20mph, when passing through school zones when kids are arriving or leaving school.

TACC is explicitly not meant for use on city streets (where school zones tend to be)- so that's user error.

I agree this is a workaround, but the basic design is just poor and potentially dangerous.

By the way: the maximum offset is 10 km/h in Europe. That's just over 6 mph. Still, 20 mph (32 km/h) won't really help if the vehicle thinks you can do 150 km/h while 80 is actually allowed.

Yeah- in the US max speed limits on highways tend to be between 55-70 mph... so a -20 offset pretty much insures the car always defaults to your current speed when you engage TACC and never exceeds the speed limit (unless the driver was already doing so)...it's weird they'd have such a useless small offset for Europe where if anything the max should be twice as large rather than half.

 

[TiggerTime]

As SSonnentag stated, you can override TACC control by pressing the accelerator. I do this all the time in my model 3. I pull off a roadway that is 50mph and the road I turn onto is 30mph but the mapping still has it as 50 mph. Just accelerate normally engage TACC and dial in the speed you want. Once you have TACC set release the accelerator and TACC will take over with whatever speed you set.

 

[DopeGhoti]

TACC is explicitly not meant for use on city streets (where school zones tend to be)- so that's user error.

What? I know that Autopilot is meant for limited-access roads, but I don't recall seeing any such notations about TACC when I reviewed the manual.

 

[arbr2]

As SSonnentag stated, you can override TACC control by pressing the accelerator. I do this all the time in my model 3. I pull off a roadway that is 50mph and the road I turn onto is 30mph but the mapping still has it as 50 mph. Just accelerate normally engage TACC and dial in the speed you want. Once you have TACC set release the accelerator and TACC will take over with whatever speed you set.

Using this approach in my example would result in the driver having to manually override TACC whilst frantically spinning the right scroll wheel down 14 times. If TACC is disengaged, the same procedure has to be repeated.

Even with 'accelerator overrule' and the 'offset workaround' I think it's safe to say that the basic design of TACC with SA in it's current form is flawed and potentially dangerous. It might also result in new drivers not using TACC and therefore not using Autosteer.

The whole point of these driver assists is to increase driver comfort and safety, TACC with SA is regularly achieving the exact opposite.

Remember that TACC with SA on Model S/X is desgined properly.

 

[totteraptor]

[QUOTE=" This behavior is dangerous and should be fixed as soon as possible.[/QUOTE]
You are absolutely right and the heading is not exaggerating. The TACC in the Model 3 is DANGEROUS! It jeopardizes people in high risk traffic zones like construction workers, school kids and cyclists.
Tesla has put a dangerous car on the streets and its just a matter of time before someone gets hurt because of it. I am trying to avoid using TACC unless i am sure it won't accelerate out of control.
@tesla - you need to prioritize to fix this above new games.

 

[Knightshade]

What? I know that Autopilot is meant for limited-access roads, but I don't recall seeing any such notations about TACC when I reviewed the manual.

Might want to read the manual again

https://www.tesla.com/sites/default/files/model_3_owners_manual_north_america_en.pdf

Traffic-Aware Cruise Control is primarily
intended for driving on dry, straight roads,
such as highways and freeways. It should not
be used on city streets.

(bold added)



Everybody complaining about how it's "dangerous" on city streets doesn't appear to be using the feature as intended.

 

[arbr2]

Everybody complaining about how it's "dangerous" on city streets doesn't appear to be using the feature as intended.

While I agree that the manual clearly states that it is not for city use, this is yet another example of why TACC with SA in it's current form is dangerous. People don't read manuals thouroughly and Tesla's manuals are often updated as well. Additionally, people are used to enabling cruise control on all sorts of roads, because it has worked for them for years. Technically you are completly correct that the manual clearly excludes city streets, but this is simply not how real-life works. Products should be designed for real-life use, this is the whole point of great design.

Anyway, my OP is about an actual real-life situation on the Autobahn in Germany, so let's just focus on that. There are many more example on highways and other main roads, but this is the most extreme example I have encountered so far and it should clearly illustrate the huge design flaws in the current system.

 

[Knightshade]

While I agree that the manual clearly states that it is not for city use, this is yet another example of why TACC with SA in it's current form is dangerous. People don't read manuals thouroughly and Tesla's manuals are often updated as well. Additionally, people are used to enabling cruise control on all sorts of roads, because it has worked for them for years. Technically you are completly correct that the manual clearly excludes city streets, but this is simply not how real-life works. Products should be designed for real-life use, this is the whole point of great design.

The two guys who killed themselves using AP where it's explicitly not meant to be used and drove under tractor trailers died in real life.

They're still idiots who died from user error though, so no sympathy there from me.

"Feature doesn't work right in places it's specifically not intended to work" is simply not a valid complaint in my mind.

W
Anyway, my OP is about an actual real-life situation on the Autobahn in Germany, so let's just focus on that. There are many more example on highways and other main roads, but this is the most extreme example I have encountered so far and it should clearly illustrate the huge design flaws in the current system.

In Germany, specifically? 100% agree. Probably the rest of the metric world too if the 10 kph max exists everywhere else too.

In the US the -20 mph trick entirely removes the concern... so the "easy" solution for Tesla is simply allow a much larger offset in metric countries.

From my understanding allowing a 40 kph negative offset would work basically everywhere except Germany since limits on major roads tend to only vary from about 80-90 to up 120-130.... thus a -40 offset would mean TACC would always engage at current speed (or at the lowest possible speed limit for the road if you're driving much below it)

Germany's a bit of a weird case as I can't think of anyplace else you'd ever see any sort of highway where the speed limit drops almost in half like that.... (in the US for example construction zones typically drop speed from 65-70 down to just 55 or so...a drop of only 16-24 kph, not 70 kph)

 

[arbr2]

Germany's a bit of a weird case as I can't think of anyplace else you'd ever see any sort of highway where the speed limit drops almost in half like that.... (in the US for example construction zones typically drop speed from 65-70 down to just 55 or so...a drop of only 16-24 kph, not 70 kph)

The offset is not designed as a workaround. As per the manual it's designed as an offset for your cruising speed in relation to the applicable speed limit. It's not designed to set current speed. Using offset in such a manner and designing a 40 km/h offset goes against its intended function and is very confusing.

The solution suggested earlier in the thread would keep all functions of TACC and SpeedAssist as designed, but just introduces a way to set to current speed. To me, this is a much more elegant and long-term solution, as SpeedAssist will one day probably be able to read speed signs and be right 99% of the time. When that day comes, TACC with SA is a great feature of the AP-suite. At the moment it has a flawed design and is potentially dangerous, not just in Germany.

Long-holding the stalk to set current cruise speed is not much more of a software challenge than introducing an enourmous speed offset.

 

[totteraptor]

Might want to read the manual again

https://www.tesla.com/sites/default/files/model_3_owners_manual_north_america_en.pdf



(bold added)



Everybody complaining about how it's "dangerous" on city streets doesn't appear to be using the feature as intended.

Does not matter what you write in a manual if you have released a dangerous product.

 

[arbr2]

Does not matter what you write in a manual if you have released a dangerous product.

I don't agree that the product (the Model 3 itself) is dangerous. The problem is that design of TACC with SA is flawed which might surprise people, especially new drivers. That might in turn result in potentially dangerous situations or speeding tickets. However, a Model 3 is an inherently relatively safe product, because it will either warn you or get you out of most of the dangerous situations.

I just very poor design that's relatively eay to fix and implement.

 

[DopeGhoti]

Does not matter what you write in a manual if you have released a dangerous product.

On the contrary, advisories in the manual for a 'dangerous product' describing how to use it safely is exactly what manuals are for.

 

[Knightshade]

Does not matter what you write in a manual if you have released a dangerous product.

Good thing they didn't do that. In fact it's arguably the safest car ever made.

But nothing is foolproof, as fools are so ingenious.

 

[DopeGhoti]

A wise man once said, "Make something idiot-proof, and some moron will come along with a better idiot."

 

[AdamMacDon]

I think part of the problem is most Tesla drivers are not privileged enough to get to drive the autobahn with their Tesla. The company is American, and here in North America our roads are trash and most speed limits are fixed, I've seen a few roads with fluctuating speed limits, but nothing like the autobahn where you can go from an unlimited speed to 80, 90, or 100 very suddenly. Another difference between driving in the EU and driving in NA that I have noticed over the years is in the EU a speed limit is just that, a limit. Most people don't exceed it by much, if at all (you guys have those sneaky speed trap Sprinter vans). In North America, our speed limits are set hilariously low. Most freeways by me are 80 or 90 kmph. So most people who have some modicum of driving skill exceed the speed limit by a large margin, usually at least 10kmph, but people will often road rage at you if you don't at least go 20kmph (12mph) over the limits. Heck most police officers do the same, if not faster, and won't harass you unless you're going dangerously fast, or they're having a bad day.

The software Tesla designed was clearly created with more of an American driving mindset than a European one, and this is a problem I think they'll run into in the pursuit of self driving: different regions have different psychology regarding driving. If you drive the "American" style in Europe, you piss people off and are a hazard. The biggest behavior issue here in NA I see is the inability to stay right. I don't have NOA so I'm not sure how it handles this, but here people are awful at staying right, and in some states it's not even a law. Unlike Germany where everyone drives very civilized and will move over as soon as it's safe.

 

[drtimhill]

The core complaint here is that the car doesn't know the actual speed limit, just the speed limit in its database.
Currently the software doesn't understand temporary speed limits.

As a result, you have to spin down the max speed setting. Fortunately it is quick to do that.

In the States there are time-of-day speed restrictions around schools, and the driver has to manually reduce the maximum speed, sometimes by 20mph, when passing through school zones when kids are arriving or leaving school.
We also have the same issue as you when going through construction zones.

I’d say anyone using TACC near a school during those times when kids are around is borderline driving irresponsibly.

 

[arbr2]

I think part of the problem is most Tesla drivers are not privileged enough to get to drive the autobahn with their Tesla. The company is American, and here in North America our roads are trash and most speed limits are fixed, I've seen a few roads with fluctuating speed limits, but nothing like the autobahn where you can go from an unlimited speed to 80, 90, or 100 very suddenly. Another difference between driving in the EU and driving in NA that I have noticed over the years is in the EU a speed limit is just that, a limit. Most people don't exceed it by much, if at all (you guys have those sneaky speed trap Sprinter vans). In North America, our speed limits are set hilariously low. Most freeways by me are 80 or 90 kmph. So most people who have some modicum of driving skill exceed the speed limit by a large margin, usually at least 10kmph, but people will often road rage at you if you don't at least go 20kmph (12mph) over the limits. Heck most police officers do the same, if not faster, and won't harass you unless you're going dangerously fast, or they're having a bad day.

The software Tesla designed was clearly created with more of an American driving mindset than a European one, and this is a problem I think they'll run into in the pursuit of self driving: different regions have different psychology regarding driving. If you drive the "American" style in Europe, you piss people off and are a hazard. The biggest behavior issue here in NA I see is the inability to stay right. I don't have NOA so I'm not sure how it handles this, but here people are awful at staying right, and in some states it's not even a law. Unlike Germany where everyone drives very civilized and will move over as soon as it's safe.

This sounds like a very plausible reason and might actually be the reason we're currently having this poor implementation of TACC with SA on M3. But keep in mind that Model S/X does have a properly designed TACC/SA system. I've driven quite a few American built cars here as well, they all have an option to set cruise control to current speed. It just doesn't make any sense to leave out a crucial element like this on Model 3 only.

There's really no defence here: TACC with SA is missing a crucial part to make it function as safely as possible. Just copy Model S/X behaviour and all is fine.

 

[North75]

I agree this behavior is annoying, but it shouldn't be surprising. The display continuously shows what the TACC speed setpoint would be if you engage it at that moment.
If it's way off from the current speed you are travelling (or want to travel) don't engage it.

 

[arbr2]

I agree this behavior is annoying, but it shouldn't be surprising. The display continuously shows what the TACC speed setpoint would be if you engage it at that moment.
If it's way off from the current speed you are travelling (or want to travel) don't engage it.

That rationale would render TACC unusable in the example I gave in my OP. As there are many situations like the example given, it would mean TACC would be unusable in many situations where it should increase driver comfort and safety. It would also render the add-on function of Autosteer useless.

That's a textbook example of poor design.

 

[richair]

@arbr2
I am glad you made this post. I am considering buying a Model 3, and this TACC behavior is seriously withholding me right now. I drive on adaptive cruise control in my current car (Audi) all the time, and I have several use cases where I drive deliberately under the speed limit (and even sometimes over). Your example of the Autobahn in a construction zone is very good, there are many more. Sometimes I just want cruise under the speed limit (e.g. 120 km/h in a 130 km/h zone) if I feel like it.

The car should not decide for me at which speed I cruise, and force me to adjust the cruising speed after every engagement of TACC (same goes for AP). The Model S does this right, and so should the Model 3.

This issue has been identified in various threads going back months and I cannot understand why Tesla is not acting on this. There are many easy fixes available, one of which you already mentioned (the press and hold to set current speed).

Another solution could to let the scroll wheel set the current speed (in the same way the Model S sets the currents speed by moving the stalk up/down). From then on, if TACC is disengaged, pulling down the gear stalk, will resume to the previously set speed. Do you want to go to the speed limit? Pull down the stalk and hold, or tap the speed limit sign on the screen.

Perhaps Tesla isn't prioritising this because it is focussing on FSD features, but until FSD is fully integrated, people will have to be in control, and have the control options to do so.