Lane Tracking Assist Issue

Speedbird: I've only had my car a few weeks now and have noticed it a couple times too. I'm touching the wheel and looking forward, so pretty sure I'm not the cause. Both times it happened at the same place, so giving me a hint. It is a neighborhood road (yea, only supposed to use it on highways, so bending the rules a bit) where the road has a hump in it and it the lines ahead aren't obvious at camera height. One other time it was a case of two road construction signs very close to each other and encroaching the lane line on the left.

My working theory is that these are times where there is something it doesn't like ahead and saying "I give up! Take over." For the road hump area it resumes control right after cresting the hump where the lines ahead are fully visible again. I'll keep observing, it is a cool feature!

will

 

It's not an error. The steering wheel does not have bio sensors to read where your hands are like some other manufacturers use. What Toyota uses to determine driver attention is steering inputs. The system needs you to make a steering input about every 15 seconds or the first warning you saw goes off. If you still don't add an input, you'll get the second warning with a chime. Eventually the system will completely shut off. All you need to do is just slightly move the steering wheel against the computer control.

I live in a rural area that's as flat as can be, where the roads are incredibly straight. I'm pretty much to the point of automatically moving the steering wheel slightly every 14 seconds.

 

Wait, really? I usually just squeeze mine and the warning goes away. If I even hold my knee lightly against the steering wheel, the computer will still steer and I won't get the warning at all

 

Those are still inputs. Either your hand or knee is fighting the LTA just enough to count as an input. It doesn't take much. Not even enough to feel the car move. Just find a straight stretch of road, set the cruise, and try out different things.

I've never tried just squeezing the steering wheel without moving it at all otherwise, but I'll try that next time.

 

It doesn't really have to be tight from my experience. I squeeze the front and back of the steering and it resets it normally. It seems to behave like a pressure sensor. A single finger on top isn't enough but a squeeze on both side will do it. There was also a video online of a guy just resting his knee on the steering for 5 min and driving it "hands free" on the highway. I've tried it and it seems to work, it didn't require any actual inputs. In a turn, the car would still turn the wheel on its on and you can feel it against your knee.

It would be cool for others to test and report! I'm half tempted to wrap a velcro strap or something on the steering wheel and see if it works for the alert (I realize it defeats the purpose of the system but it's more of a curiosity).

 

I suspect what's happening in both those cases is that the car is still recording a steering input. When you're gripping the wheel tightly, you're probably holding it strongly enough to "fight" the LDA just enough to trigger the input. The same goes for using a knee. Resisting the LDA counts the same as an input.

I'm still going to test it myself the next time I'm highway driving. The trick is going to be gripping tightly with the hand while still keeping the wrist and arm loose. There needs to be compression pressure on the steering wheel rim, but no rotational torque against the steering shaft.

 

I guess I've assumed it is a capacitive sensor that is set to be not very sensitive. If I'm not touching it enough, I get this too. But if I touch it with more of my hand (not squeezing it moving), it goes away. There are a lot of capacitive sensors in the car, so that's why I assumed it was this. If you have lower iron content in your blood or smaller hands, maybe it is not as sensitive to your touch. Capacitive sensors react to your body's electric field so lower iron content or lower surface area will make them not as sensitive.

 

This is interesting reading. Since the manual says steering wheel covers or gloves may prevent hand detection I assumed it was cap sense of some kind. Yea, if it is any kind of force input, then a cover or gloves shouldn't matter. A knee probably does count even for cap sense though. This will be some fun tinkering the next time I drive. I'm resorting to just tapping my fingers on to the wheel lightly while driving.

will

 

I use my index finger hooked at the bottom of the wheel where the spoke and rim meet and just pulse a bit of torque into it every 10sec or so.

 

If the prompts are ignored, does the cruise control system completely shut down? Just curious since if thats the case, just randomly shutting down at the middle of the highway.

 

I find this feature annoying so I turned it off. Problem solved for me

 

Blackat: This is my first car with the feature and it is a bit disconcerting at first. I'm at a bit over a month now of actively trying to use it and I'm starting to like it. Last week I drove my old Gen1 Prius to a nephew 60 miles away, so it felt a bit weird not having the car "encourage" me to be perfectly centered. Maybe give it a try again later. Like all the features though, it is nice to be able to turn most of them off.

will

 

I would probably use it on a trip with long straight roads. I sometimes need to make quick lane changes and don't like the car "fighting" me.
It is a nice feature to be able to turn it on and off.

 

It's definitely not a capacitive sensor. I've done plenty of tests, and have found that it has absolutely no connection with how much I'm touching/gripping the wheel. If the road is straight enough and the car can go long enough without needing to adjust the steering input, I can white-knuckle grip the wheel at any position, with both hands, and will still get the warning message. But the moment I try to turn the wheel even slightly, or the car makes a steering adjustment and I resist it, it goes away.

Essentially, the car is always measuring the wheel position at all times. When it makes a steering adjustment, it knows where it should expect the wheel to be positioned after the adjustment. If, at any point, the wheel position doesn't match the expected position, it knows the driver has either provided a direct input, or has resisted the car's adjustment.

I get this warning super frequently and it's the thing that annoys me the most about lane trace assist. I just resigned myself to having to constantly 'bump' the wheel every 15 seconds to deter the warning.

I can only assume the bit about covers and gloves is just generic writeup for any wheel-based driver sensing systems they might put in place, so they don't have to keep that part of the manual updated for the specific model if they decide to change the sensing mechanism or something.

If you use your turn signal when switching lanes, it temporarily disengages LTA so it won't fight you.

Ignore the warnings long enough and the car will assume you've fallen asleep and slow to a stop.

 

Yeah, I get that. Unfortunately there are lots of pot holes where I live and have to take evasive action. Lol

 

Concur on the turn indicator temporarily overriding lane keeping. It also serves as a good reminder if you forgot to start them before trying to change lanes! "Oh no you don't!" I've had mixed results on the car centering itself in the new lane by itself, but suspect that may be my fault still. It keeps on going and I suspect it is because I had the turn indicator "hard on". I'm not used to the temporary turn indicator mode yet. That is something new to me and not muscle memory yet.

Agree on potholes vs auto lane keeping. After having to override the lane keeping to avoid some potholes recently, I was wondering: How do the fancy "full" auto driving cars handle potholes? Do they just hit them?

will