Lane trace assist

[RobN-RG]

Took my new Yaris on the motorway today and tried out the lane trace assist function.  Really weird. It felt like the car was zig zagging on the road.

Holding the steering wheel lightly, it nudged to the left, then the right and seems to keep doing it.  Even on a straight bit of road it didn't want to keep the wheel still. 

Anyone else experienced this? 

[Mikw]

2 hours ago, RobN-RG said:

Took my new Yaris on the motorway today and tried out the lane trace assist function.  Really weird. It felt like the car was zig zagging on the road.

Holding the steering wheel lightly, it nudged to the left, then the right and seems to keep doing it.  Even on a straight bit of road it didn't want to keep the wheel still. 

Anyone else experienced this? 

From time to time, yes.

Other times it's pretty good. Seems to have good and bad days.

[CPN]

It depends a lot on the road you are on and how clear the markings are.

[Bernard Foy]

Yes mine is the same it over corrects and doesn’t respond quickly enough to correct the oversteer. It’s not really helpful, in fact as far as I’m concerned it’s a bit of a nuisance.😡🚗

[MikeSh]

What is the actual intention of the system?

Before you say "Duh!" I don't have a 4th Gen but my previous car (not Toyota) did have lane 'thingy'.

That one had two modes: in normal driving it had 'lane keep assist' which would nudge the steering if the car got too close to (what it thought) was the edge of the lane. The reported 'problem' above sounds like that kind of intention - not steering for you, just catching excess drift.

When cruise control was engaged it became 'lane follow assist' where it would actively steer to keep the car in (again what it thought was) the middle of the lane. It was a low level autonomous driving function.

It may not seem much of a difference but if you are expecting one and get the other, especially in a wide lane, ... it is.

[RobN-RG]

9 hours ago, MikeSh said:

What is the actual intention of the system?

It's supposed to keep you in the middle of the lane. Lane departure warning is the other thing that beeps if you stray too close to the line.  

Like I said, this was on the motorway, so good markings, but quite wide. My impression was that the car is saying "I can see the left line, but not the right, I better nudge right. Ah, there it is.  Now where's the left one gone, I better go left a bit to find it. Now where's the right one gone..." - hence the mild zig zag.  If it could see both at the same time it could stay in the middle. 

[Catlover]

The usefulness of Lane Assist is to remind you are drifting a little, as in “you are dozing, stay alert”. So that’s a good thing, I thought you can adjust the sever ness of the tug away the other lane.

[MikeSh]

2 hours ago, RobN-RG said:

It's supposed to keep you in the middle of the lane.

 

2 hours ago, Catlover said:

The usefulness of Lane Assist is to remind you are drifting a little,

 

So that's two different answers - one thinks it's 'follow' and the second 'keep in'.

What does the manual say? (If anything sensible 🙂 )

[CPN]

2 hours ago, Catlover said:

The usefulness of Lane Assist is to remind you are drifting a little, as in “you are dozing, stay alert”. So that’s a good thing, I thought you can adjust the sever ness of the tug away the other lane.

You are right. You can adjust its sensitivity in the menus on the dash...

[CPN]

54 minutes ago, MikeSh said:

So that's two different answers - one thinks it's 'follow' and the second 'keep in'.

What does the manual say? (If anything sensible 🙂 )

"When driving on highways and freeways with white (yellow) lane lines, this function alerts the driver when the vehicle might depart from its lane or course* and provides assistance by operating the steering wheel to keep the vehicle in its lane or course*. Furthermore, the system provides steering assistance when dynamic radar cruise control with full speed range is operating to keep the vehicle in its lane. The LTA system recognizes white (yellow) lane lines or a course* using the front camera. Additionally, it detects preceding vehicles using the front camera and radar.
*: Boundary between asphalt and the side of the road, such as grass, soil, or a curb"

(Page 219)

This is one area where the HUD (if fitted) becomes really useful as you can instantly see whether the car has "lost sight of" either side of the lane you are in without having to take your eyes off of the road ahead. It's a bit more difficult to see the indicators down in the dash panel... (safely anyway).

Forgot to mention that you can turn off the lane assist whilst still keeping the adaptive cruise control active. (two buttons on the steering wheel - one to vary the distance between you and the vehicle in front and the other to deactivate the lane assist (only))

[MikeSh]

Okay. It's like my previous car then. You only get self-steering in cruise control mode.

Normal driving just kicks it when you get to the lane edge, which sounds like the OP's description.

[Hadrian1]

It's more noticeable on a narrow road. Mine seems to come on by default (that's the lane assist, not cruise control).

You can cancel it though.

[Cyker]

I find if you let it do its thing on a straight it eventually settles, but sometimes it does veer a bit too close to the left/right-side while it's settling which forces you to correct or risk scaring other road users. Strong shadows confuse the hack out of it tho' - I had to turn it off and just use the radar cruise alone on the way home yesterday because it kept beeping at me because of the alternating tree shadows confusing it. So glad they put the button for this on the steering wheel! Shows a real person tested it and thought it would be beneficial for the driver to have a dedicated quick-access control toggle!

Tesla - Take note!

I have been using it extensively in my daily journeys during the boring bits, but always take over when things start to get 'interesting'...!

I'd rate it 75% effective, but as it's meant as a driving 'assist' and not self-driving I guess that's okay. It does make runs up the M1 a lot less fatiguing!