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Discussion Starter #1
What is the difference between these two systems? It seems to me they are virtually the same.
 

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LKAS (Lane Keeping Assist System) must be turned on each time the vehicle is started. This feature applies steering torque to help keep the vehicle between the lane markings.

RDM (Road Departure Mitigation) stays on or off depending on your setting. This feature will beep, display a message, and shake the steering wheel if it thinks you're going to run outside of your lane without using the turn signal. If it thinks you are leaving your lane, it will apply steering torque to bring you back into the lane and apply the brakes if that doesn't work.
 

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LKAS (Lane Keeping Assist System) must be turned on each time the vehicle is started. This feature applies steering torque to help keep the vehicle between the lane markings.

RDM (Road Departure Mitigation) stays on or off depending on your setting. This feature will beep, display a message, and shake the steering wheel if it thinks you're going to run outside of your lane without using the turn signal. If it thinks you are leaving your lane, it will apply steering torque to bring you back into the lane and apply the brakes if that doesn't work.
I don't recall having to enable this every time the vehicle is started. Then again, I always have my cruise on which enables LKAS.
 

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I don't recall having to enable this every time the vehicle is started. Then again, I always have my cruise on which enables LKAS.
Not exactly. Turning the "cruise main" (MAIN button on the steering wheel) on illuminates the ACC and LKAS indicators to tell you that those feature are ready for use. LKAS isn't active until you press the LKAS button which you have to do every time you restart the vehicle.
 

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Not exactly. Turning the "cruise main" (MAIN button on the steering wheel) on illuminates the ACC and LKAS indicators to tell you that those feature are ready for use. LKAS isn't active until you press the LKAS button which you have to do every time you restart the vehicle.
I see what you are saying and what is in the manual on pgs 470-476 but with my experiences, I'm not sure it works how it is written. On my RTL-E, I have the compass take up the full center display. If I press the LKAS button on the wheel, it displays on the right side like shown on pg 472. For every day driving, I do not have it up there or push the button to put it up there. With just the compass displaying (no LKAS button pressed) and I drift too far left or right in a lane, the system will pop up the LKAS in the full screen and show me which way I have drifted and prompt for steering input. I can still feel it provide assistance in to curves as well. From what I read and my daily driving experience you just need to leave the Main button turned on which enables LKAS and ACC, even when you power the RL off/on. My understanding of the LKAS Button from the delivery check was just to display the LKAS lane markings on the dash if you wanted it up there. I do use it on some of the farm roads out by me or in bad weather to get an idea of what the camera can see and when it drops the lines out.

I need to grab my kid's GoPro and see if I can set it up to record what I'm experiencing. I'll play with the LKAS button on my drive home today and see if it changes how things work. There are a couple rest stops I can use to power my RL off and on as well.
 

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I use my LKAS every day, and all I have to do is press the "Cruise Main" button.
 

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Sidebar on Pg 458 says:
When the MAIN button is pressed, both ACC and
the Lane Keeping Assist System (LKAS) are either
turned on or off.

Edit
Pg 472 says:
Press the MAIN button.
The ACC and LKAS indicators come on.
The system is ready to use.

Confusing!
 

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I see what you are saying and what is in the manual on pgs 470-476 but with my experiences, I'm not sure it works how it is written. On my RTL-E, I have the compass take up the full center display. If I press the LKAS button on the wheel, it displays on the right side like shown on pg 472. For every day driving, I do not have it up there or push the button to put it up there. With just the compass displaying (no LKAS button pressed) and I drift too far left or right in a lane, the system will pop up the LKAS in the full screen and show me which way I have drifted and prompt for steering input. I can still feel it provide assistance in to curves as well. From what I read and my daily driving experience you just need to leave the Main button turned on which enables LKAS and ACC, even when you power the RL off/on. My understanding of the LKAS Button from the delivery check was just to display the LKAS lane markings on the dash if you wanted it up there. I do use it on some of the farm roads out by me or in bad weather to get an idea of what the camera can see and when it drops the lines out.

I need to grab my kid's GoPro and see if I can set it up to record what I'm experiencing. I'll play with the LKAS button on my drive home today and see if it changes how things work. There are a couple rest stops I can use to power my RL off and on as well.
I use my LKAS every day, and all I have to do is press the "Cruise Main" button.
The purpose of LKAS (Lane Keeping Assist System) is to keep you inside the lane without getting too close to the lane markings by using steering torque.

The purpose of RDM (Road Departure Mitigation) is to apply additional steering torque if you begin to cross the lane markings and apply the brakes if you do.

RDM includes LDW (Lane Departure Warning) to issue a visual and audible warning and shake the steering wheel to let you know you're too close to a lane marking.

LKAS does not operate until you press the LKAS button on the steering wheel and the lane markings appear solid on each side of the vehicle graphic in the multi-information display.

RDM stays on or off depending on your setting and operates whether or not LKAS is on.

Some people seem to confuse RDM's ability to apply steering torque as LKAS, but the two functions are different.

Sidebar on Pg 458 says:
When the MAIN button is pressed, both ACC and
the Lane Keeping Assist System (LKAS) are either
turned on or off.

Edit
Pg 472 says:
Press the MAIN button.
The ACC and LKAS indicators come on.
The system is ready to use.

Confusing!
Pressing the MAIN button to "turn on" ACC and LKAS means just that - turning them on (or "arming" them, if you will). That's not the same as actually using them.
 

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Following the newfound information from @zroger73 I took a short trip this morning actually using the LKAS and the feeling is entirely different than RDM which I previously thought was LKAS. The description for LKAS is quite clear in the Owners Manual, but I never read that description because I thought I knew how it worked.

I also realize the salesman who gave me an extensive preview of vehicle features did not understand the difference between LKAS and RDM either.

Waiting for the report from @JJkroch after his extended experience, but I think the actual LKAS will provide an experience that is far better than RDM by itself. I always disliked the slowing I felt when drifting close to the lane markings, which I now understand is the braking RDM applies when crossing the lines.

I will have an opportunity in two days for a better experience because I will travel about 60 miles on freeways when we visit my daughter. I will then know if LKAS is as smooth as I expect.

I also like the lane indicators on the DIC when LKAS is activated giving an indication when the lane markings are recognized by the system.
 

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Following the newfound information from @zroger73 I took a short trip this morning actually using the LKAS and the feeling is entirely different than RDM which I previously thought was LKAS. The description for LKAS is quite clear in the Owners Manual, but I never read that description because I thought I knew how it worked.

Waiting for the report from @JJkroch after his extended experience, but I think the actual LKAS will provide an experience that is far better than RDM by itself. I always disliked the slowing I felt when drifting close to the lane markings, which I now understand is the braking RDM applies when crossing the lines.

I will have an opportunity in two days for a better experience because I will travel about 60 miles on freeways when we visit my daughter. I will then know if LKAS is as smooth as I expect.

I also like the lane indicators on the DIC when LKAS is activated giving an indication when the lane markings are recognized by the system.
Don't expect too much from LKAS and maybe you won't be disappointed. :)

On each of the five Hondas I've owned with the feature, I find that it slowly oscillates around the center of the lane like a drunk driver and often works against my natural tendency to keep the vehicle perfectly centered in the lane. If you relax and let it take you outside of your comfort zone and do its thing, it's less intrusive. It works best on straight, flat roads with dark asphalt and fresh markings.
 

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On my trip home tonight the LKAS worked without me pressing any buttons to enable. Pushing the LKAS button just removed the lane markings from the center screen. The departure mitigation is turned off/on by a button on the lower left of the dash. Turning the main button off on the steering wheel disable LKAS and ACC.


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On my trip home tonight the LKAS worked without me pressing any buttons to enable. Pushing the LKAS button just removed the lane markings from the center screen. The departure mitigation is turned off/on by a button on the lower left of the dash. Turning the main button off on the steering wheel disable LKAS and ACC.


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LKAS is active only when you see solid lane markings in the multi-information display. Any other behavior suggests your vehicle is not operating as designed.
399794
 

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Discussion Starter #13
So I continue to learn. I now understand both systems better. Thank you all. What I have learned is the driving experience suffers when you have both systems on at the same time. Especially when I also had the cruise control on. The truck seemed to speed up and abruptly slow down frequently. Now that I better understand the two systems that does not surprise me. I dont think it's hurting anything other than gas mileage but it was disconcerting. Living here in NH and driving mostly curvy roads with few straights may have something to do with that too. So the ACC (cruise control) works well with the LKAS but if you have that on don't turn or leave the RDM on. One or the other but not both. Drives a lot smoother that way. YMMV.
 

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So the ACC (cruise control) works well with the LKAS but if you have that on don't turn or leave the RDM on. One or the other but not both. Drives a lot smoother that way. YMMV.
That doesn't make sense because RDM doesn't intervene unless you begin to leave your lane.
 

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I did more "testing" this past weekend on a drive from Columbus to Normal Il and back. With the cruise not enabled, you need to have the lane markings on the display to get LKAS functionality. You do not have to press the button every time you start the vehicle to get it to work. If it was displaying prior to shutting off the RL, it was back on when started up.

Now here is where it gets interesting. If you have Cruise on, you don't need to have the lane markings displayed, you get LKAS functionality. If you ignore RDM, it will nag and slow you down. Messed with this config a few times and even had my son drive for a while to get his experiences. They lined up with the feedback I was getting from the RL.
 

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You're getting warmer. :)

With the cruise not enabled, you need to have the lane markings on the display to get LKAS functionality. You do not have to press the button every time you start the vehicle to get it to work. If it was displaying prior to shutting off the RL, it was back on when started up.
The green LKAS indicator will remain on or off after restarting the vehicle, but that indicator does not mean LKAS is "active" - it means that the function is "ready for use". LKAS becomes active only after you press the LKAS button on the steering wheel which causes the lane markings to appear in the Multi-Information Display. LKAS will then apply steering torque to keep the vehicle between the lane markings when the lane markings in the Multi-Information Display are solid (as opposed to outlined).

Now here is where it gets interesting. If you have Cruise on, you don't need to have the lane markings displayed, you get LKAS functionality. If you ignore RDM, it will nag and slow you down. Messed with this config a few times and even had my son drive for a while to get his experiences. They lined up with the feedback I was getting from the RL.
Again, LKAS is actively able to apply steering torque only when solid lane markings appear in the Multi-Information Display.

The only other function of Honda Sensing that provides steering torque is RDM.

Site note: On some Honda models. setting the ACC also activates SDA (Straight Driving Assist) - a function that helps compensate for natural steering pull caused by conditions such as a side wind or road crown. The Ridgeline does not have SDA.

To summarize: LKAS applies steering torque in an attempt to keep the vehicle centered in a lane. It is active and able to apply steering torque only when solid lane markings appear in the MID.

LKAS tries to keep you from leaving your lane.
LDW warns you if you're about to leave your lane.
RDM steers and brakes if you're leaving your lane.
 

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Yes, the green indicator remains on after stopping and restarting the RL and if the LKAS lane markings were on in the center display, they were back on after the restart. They will not go solid until the computer can identify the center/shoulder markings. There was some confusion that you needed to press that lower steering wheel button every time to get the lane markings up on the dash and reenable the system.. I've found that not to be the case.

Either way, I think I'll leave the lane markings on my center screen going forward. Paid for those options, I might as well use them as the engineers intended.

Good info zroger73, Appreciate the feedback and knowledge sharing
 

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...if the LKAS lane markings were on in the center display, they were back on after the restart.

There was some confusion that you needed to press that lower steering wheel button every time to get the lane markings up on the dash and reenable the system.. I've found that not to be the case.
That operation is neither intended, explained in the Owner's Manual or service information, nor observed in my own 2017 or 2019 Ridgelines, 2019 RDX, 2018 Accord, 2016 CR-V, or other Honda and Acura vehicles equipped with Honda Sensing that I've driven.

Per the Owner's Manual, the "MAIN" (which turns on the green LKAS and ACC indicators) remains in the selected state after a restart. The lane outlines should not reappear after a restart until you press the LKAS button on the steering wheel. If yours operates differently, I can only conclude it is faulty.

400585
 

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That operation is neither intended, explained in the Owner's Manual or service information, nor observed in my own 2017 or 2019 Ridgelines, 2019 RDX, 2018 Accord, 2016 CR-V, or other Honda and Acura vehicles equipped with Honda Sensing that I've driven.

Per the Owner's Manual, the "MAIN" (which turns on the green LKAS and ACC indicators) remains in the selected state after a restart. The lane outlines should not reappear after a restart until you press the LKAS button on the steering wheel. If yours operates differently, I can only conclude it is faulty.

View attachment 400585
Hence the confusion because on my 2019 it does not operate that way.


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