The dangers of TACC with Speed Assist

[arbr2]

As of software version 2019.32.12.1 a small part of this issue has been addressed by Tesla. As of this version the TACC will no longer set speed to 150 km/h in an unrestriced zone. It will now default to 130 (or higher when going over 130 km/h).

While this at least reduces the number of scroll by 4, it still requires 10 frantic scroll to set speed to 80 km/h if needed. It will also still result in unexpected acceleration in speed restricted zone. This still isn't a solution to the problem.

There should be a clear intention from the driver to set TACC to the speed limit.
I still feel like this implementation would be most intuitive and safe:

- Stalk down and release = set to current speed
- Stalk down and hold = set to speed limit +/- offset (or current speed if above)

There is also a 'bump' on the stalk down movement when fully depressed down. That could also be used to set to max speed, but I feel like Tesla is reserving that interaction for something else. As far as I can tell the bump doesn't do anything at the moment, so that might also be a great way to set TACC to the speed limit with intention.

As long as there is a clear input by the user that the max speed should be set instead of current speed, the design should be much safer and more intuitive than it is now.

 

[totteraptor]

As of software version 2019.32.12.1 a small part of this issue has been addressed by Tesla. As of this version the TACC will no longer set speed to 150 km/h in an unrestriced zone. It will now default to 130 (or higher when going over 130 km/h).

While this at least reduces the number of scroll by 4, it still requires 10 frantic scroll to set speed to 80 km/h if needed. It will also still result in unexpected acceleration in speed restricted zone. This still isn't a solution to the problem.

There should be a clear intention from the driver to set TACC to the speed limit.
I still feel like this implementation would be most intuitive and safe:

- Stalk down and release = set to current speed
- Stalk down and hold = set to speed limit +/- offset (or current speed if above)

There is also a 'bump' on the stalk down movement when fully depressed down. That could also be used to set to max speed, but I feel like Tesla is reserving that interaction for something else. As far as I can tell the bump doesn't do anything at the moment, so that might also be a great way to set TACC to the speed limit with intention.

As long as there is a clear input by the user that the max speed should be set instead of current speed, the design should be much safer and more intuitive than it is now.

Fully agree - that is the perfect solution to implement! Please Tesla, please

 

[ravejads.tmc]

...
- Stalk down and release = set to current speed
...

Honestly if they just implemented this I would be happy. There are too many situations where accelerating (usually aggressive acceleration) is the wrong this to do. Just set the cruise at the current speed no matter what. The driver can then adjust the speed from there with the dials.

 

[youngmcdonald]

I didn’t read this entire thread. This has been discussed a lot in another thread where I criticized this “feature” quite a bit.

But one of the most helpful posts on there that can help alleviate the TACC’s shortcoming to not set the cruising speed to your current speed is to NOT release the accelerator pedal when you engage TACC until you adjust your speed to your desired limit. Meaning, if you’re driving at 60 mph but the maximum limit for that road is 75 mph, when you engage TACC, keep the accelerator pressed, use the right scroll wheel to bring the speed down to say, 60 mph, and then release the pedal.

If you release the pedal right after engaging TACC given that is how every other car works, this car will instantly accelerate to 75 mph from 60 mph and it is dangerous. Fanboys defend this bug as a feature but it is what it is. But there IS a workaround and this is it.

 

[DopeGhoti]

Aha! So I was not imagining things when I felt like TACC was slow on the upkeep when "helpnig" the car when it was slow to take off in formerly stopped traffic. That explains things perfectly and also is a fine workaround for this suboptimal design.

 

[totteraptor]

I didn’t read this entire thread. This has been discussed a lot in another thread where I criticized this “feature” quite a bit.

But one of the most helpful posts on there that can help alleviate the TACC’s shortcoming to not set the cruising speed to your current speed is to NOT release the accelerator pedal when you engage TACC until you adjust your speed to your desired limit. Meaning, if you’re driving at 60 mph but the maximum limit for that road is 75 mph, when you engage TACC, keep the accelerator pressed, use the right scroll wheel to bring the speed down to say, 60 mph, and then release the pedal.

If you release the pedal right after engaging TACC given that is how every other car works, this car will instantly accelerate to 75 mph from 60 mph and it is dangerous. Fanboys defend this bug as a feature but it is what it is. But there IS a workaround and this is it.

Thanks for sharing the tip. Call me fuzzy but I still feel Tesla need to change to a more elegant solution.

 

[arbr2]

But one of the most helpful posts on there that can help alleviate the TACC’s shortcoming to not set the cruising speed to your current speed is to NOT release the accelerator pedal when you engage TACC until you adjust your speed to your desired limit. Meaning, if you’re driving at 60 mph but the maximum limit for that road is 75 mph, when you engage TACC, keep the accelerator pressed, use the right scroll wheel to bring the speed down to say, 60 mph, and then release the pedal.

If you release the pedal right after engaging TACC given that is how every other car works, this car will instantly accelerate to 75 mph from 60 mph and it is dangerous. Fanboys defend this bug as a feature but it is what it is. But there IS a workaround and this is it.

Yeah, I've highlighted this in this thread as well. I wouldn't call it a workaround, as the user still needs to be aware of this behaviour as well as requiring the user to scroll down 14 times to the desired speed. But I agree: without this, TACC would be downright dangerous and almost impossible to use in quite a few situations.

Thanks for highlighting it again, however the core issue still remains: TACC's speed selection design is flawed and can be dangerous and a fix would be very simple to implement.

 

[DopeGhoti]

TACC would be downright dangerous and almost impossible to use in quite a few situations

"Quite a few" implies (to me, at least), plurality, which in my opinion is overstating the problem. In most situations, TACC applies the true and correct speed limit, and in general, if you have cause to be going significantly slower than that limit is is due to surrounding traffic, which TACC already allows for gracefully.

This is not to say that there's a very good argument to be made that the design is flawed; given how software-driven the vehicle is, if Tesla is not inclined to add a "long-press-for-current-speed" TACC activation mode, perhaps that could add a toggle in the Autopilot settings session to allow the user to select between the current behavior and always using current speed as the TACC target.

 

[arbr2]

"Quite a few" implies (to me, at least), plurality, which in my opinion is overstating the problem. In most situations, TACC applies the true and correct speed limit, and in general, if you have cause to be going significantly slower than that limit is is due to surrounding traffic, which TACC already allows for gracefully.

I really do think plurality applies here. Maybe in the US there might be significantly less situations where the dangerous behaviour applies, but in Europe there is a wide range of situations where TACC is simply dangerous. See my OP for the most extreme example, but there are many many more. Like reduced speed zones due to traffic (very common during rush hour): the speed limit is reduced to 50, while 120 woud be normal. The car wants to go 120, but only 50 is allowed. Even in rush hour, there might not always be a car right in front of you, so TACC will still accelerate way over the speed limit, while the rest of traffic is actually slowing down. This can happen on a daily basis.

 

[youngmcdonald]

Despite several software iterations, this car still cannot seem to stop swerving to the right and hugging the right lane when driving close to lane mergers and on ramps. I’m talking about USA. Even if they fix that, I think it’ll be a phenomenal improvement to lane tracking. In my opinion that’s the only issue that truly makes other drivers around you think of you as a drunk and stupid driver.

Aside from few instances of phantom braking and the initial set speed issues, I do think adaptive cruise control works fairly well on highways. One shouldn’t be using it in cities anyway.

 

[DopeGhoti]

I've noticed in the latest versions of V10, that when I'm in a lane that just lost its "merge lane" partner to the right, while the car will still want to center itself in the lane (which, I'll be honest, I tended to do myself anyhow), I'm able to hold the car to following the left lane line by resisting AP's pull on the wheel, and AP will, interestingly, not disengage. I'm wondering if this is how we're supposed to help train the neural net.