2017~2024 MRCC vs. "Cruise Control" - Two Different Things?

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181962

The vehicle in question is the 2020 CX-5 Touring AWD with zero options:

When I purchased the car I asked the salesman if I could turn off the Mazda Radar Cruise Control (MRCC) headway control, the cruise control function that slows the vehicle as a slower car is approached. In other words, can I operate cruise control in the old school way? I'd like to get rid of headway control if it can be avoided. He said no.

Now I'm reading a note on page 4-159 in the MRCC section of the manual that describes "Switching to Cruise Control Function." The way that reads, and the way this manual has different sections that seem to talk about MRCC and "Cruise Control" as two different things, the 4-159 verbiage seems to suggest one can switch to old school cruise control.

I'd prefer not to experiment with this in live traffic. Does anybody know if the steps on page 4-159 really switch it to old school cruise mode? And if so, are any other functions turned off in the process like emergency braking?
 
You should be able to toggle between regular cruise control and adaptive cruise control on your steering wheel.
 
You should be able to toggle between regular cruise control and adaptive cruise control on your steering wheel.
I've heard the same thing. I think the default is adaptive and if you press the On again you get regular although I've never tried it because adaptive is better.
 
Yes the manual is correct. You can toggle between the two. In some situations I prefer regular cruise control as well. I don’t think this affects the other safety functions since these are operational regardless of cruise control being on or not.
 
So, you guys have emboldened me to go out on a nearby country road where I determined the following:

The short answer is you toggle back and forth between MRCC and old school cruise with the ON/MODE button. First, hit the ON/MODE button which will put you in MRCC mode by default pending your speed setting. Then press and hold the ON/MODE button to switch to old school mode. A more detailed answer is:

1) Staring up in accessory mode, after the engine is started, or when you are underway, it doesn't matter, press the steering wheel MODE/ON button. It defaults to MRCC mode. You know this because the industry standard icon appears in the right side display except with a modification: a little car appears in the icon above the circle. It's that little car that tells you are in MRCC mode. The display icon is white at that point

2) Once you set your speed, the icon turns to green and MRCC is activated.

3) If you press and hold the MODE/ON button at any time after startup while in that default MRCC mode as in 1) above, whether in accessory mode, in park after starting, underway, or even with MRCC activated with the speed set (green icon with car) , a message is displayed briefly in the right circular display which reads, "Mazda Radar Cruise Contral Deactivated." Once that message disappears you will see the crusie icon has switched to the school icon (white) without the little car and you are in old school cruise control with the speed not yet set. Once you set the speed the icon turns green.

4) If you change from MRCC to old school while the MRCC speed is set (green icon with little car), the speed setting turns off (like the CANCEL function ordinarily), the icon switches to the old school icon without the little car and is displayed in white. You will be coasting at that point if your foot is not on the gas and you'll need to reset your speed.

5) If you shut off the engine while in old school mode, it will default back to MRCC when you restart, so you will always be in MRCC at startup when you activate cruise.

It is pretty simple actually. But go ahead and read the instuctions on page 4.159 and tell me if this is what you would have gleaned. Good luck with that.

I still don't know if switching off MRCC might also switch off other functions that use the same radar. That's a matter for another day.
 
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I've heard the same thing. I think the default is adaptive and if you press the On again you get regular although I've never tried it because adaptive is better.
It's not that adaptive is better. It's a preference.

I only use cruise on expressways. It's rare to encounter somebody driving at my desired speed while keeping their speed steady. In those rare cases (where that other guy is probably on cruise), the adaptive function looks like a good idea...until his adaptive cruise slows him down behind a pokey driver.

I prefer old school. If I'm coming up on somebody in the right lane, I'll do one of two things. I'll just pass him if the left lane is clear. If the left lane has passing traffic present or dangerously approaching, I'll hit the cancel button, coast down and use gas if necessary to maintain speed while I wait. As soon as the left lane is clear I hit the resume button as I move into the left lane to pass, maybe a bit before changing lanes depending on circumstances.

With adaptive cruise, when you go to pass, you have to be well into the left lane before the vehicle starts accelerating back to the set speed. That's as you would expect--the radar needs to get to where there is nothing in front of it. I just don't like the lag in the timing of that acceleration and not knowing the precise point when it will occur. Cancel-coast-resume in old school mode is simple and works for me.

Of course you would not want to use the adaptive cruise together with lane keeping, automatic braking, yada, yada to drive autonomously while taking your eyes off the road. No systems in existance are anywhere near good enough for that. On the other hand, adaptive could save you from driving into somebody's rear end if you're distracted. So, one has to be realistic about one's driving habits with phones and such; adaptive might be better if prone to distration.
 
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Yes the manual is correct.
The manual gives indications but I can't say the step-by-step it provides is at all clear. Kinda misleading, acutally.
I don’t think this affects the other safety functions since these are operational regardless of cruise control being on or not.
That's probably right, but it's not like I'm going test automatic emergency braking to find out. 😮 There may be something in the manual about this that I've not gotten to yet.
 
The manual gives indications but I can't say the step-by-step it provides is at all clear. Kinda misleading, acutally.

That's probably right, but it's not like I'm going test automatic emergency braking to find out. 😮 There may be something in the manual about this that I've not gotten to yet.

In my 2018 CX-9, the manual isn't very clear either on how to activate it. I press mode once to turn on MRCC (white MRCC symbol (speedometer with a little car on top)). Then I hold mode again until the MRCC switches to cruise control (get message that MRCC is off and the symbol changes to cruise control symbol (speedometer without the little car above it)).

I tried it this evening and in cruise control mode the car detection indicators still showed the Radar had detected a car in front of me when there was one. This leads me to believe that the Radar remains operational, which is another indication that the other safety features might remain active.
 
I tried it this evening and in cruise control mode the car detection indicators still showed the Radar had detected a car in front of me when there was one. This leads me to believe that the Radar remains operational, which is another indication that the other safety features might remain active.
This is correct. Using standard cruise control does not turn off the other safety features.
In my 6, even with the cruise turned completely off, I still get the indication on the dash if there is a car in front of me. Radar is on all the time.
 
With adaptive cruise, when you go to pass, you have to be well into the left lane before the vehicle starts accelerating back to the set speed........
You can just put your foot on the accelerator pedal during that transition phase of lane changing / following distance until your in the clear lane.

I probably use the MRCC on two-lane roads where I'm not planning to pass anyone and not in any particular hurry more than I like it on the highway. I set the following distance out to the max (4 bars) and let it do it's thing.
 
I like both systems based on the situations. And it is totally a question of personal preferences.

Just like HyFlyer I use it on two lane roads, and I really like it in higher traffic highways where the speed varies a lot.

On long road trip on non congested highways, I prefer regular cruise control because it pisses me off to realize that I have been driving slower than I wanted for the last 15 minutes because I did not realize the MRCC progressively slowed me down to match the speed of the car in front of me (or that the car in front of me was driving faster before and decided to slow down without me noticing).
 
you can just put your foot on the accelerator pedal during that transition phase of lane changing / following distance until your in the clear lane.
I'm not keen on the idea of giving one acceleration instruction to the vehicle with the gas pedal and then moving into the passing lane where MRCC has a different acceleration instruction from the cruise set point and the systems rate of acceleration..

With old school cruise, I wouldn't hit resume to have the car accelerate up to the set point while using the gas to get there faster. My attention is on the road, not the speedometer. Overshooting the set point and then having the vehicle start decelerating at a different rate than I intend as I ease off the gas is not a great idea in my book. If I want to do that I simply accelereate with gas at the rate I want up to the speed I want in cancel mode then decelerate in the way I want and then resestablish the set point.

Frankly, the only time I use cruise is for long stretches because of lower back issues. My leg starts to go numb within two hours if I'm constantly working the gas pedal. If I can flex my right leg periodically and reposition a bit in the seat I can go longer.

I did not mean to start a debate on which methods are better. As I said, it's a preference, and MRCC could be particularly valuable in situations where there's attention deficit, to which we all are subject to one degree or another. That's true of many of these safety features. For my part, when I'm driving with my wife and she says, "Oh, look at that!," my stock response is, "I'm driving here."

I started this thread to figure out how the d*mn thing works with the manual not being of much help. I've got my answer and that's a good thing.
 
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In my 2018 CX-9, the manual isn't very clear either on how to activate it. I press mode once to turn on MRCC (white MRCC symbol (speedometer with a little car on top)). Then I hold mode again until the MRCC switches to cruise control (get message that MRCC is off and the symbol changes to cruise control symbol (speedometer without the little car above it)).
Right, that's what I described above for my 2020 though the manual is quite poor in explaining it.

I'd like to reemphasize an earlier point. If you are in either MRCC or old school cruise, tooling along with the system engaged, you can swith to the other mode on the fly. But you need to know that the set point from the original mode you were in is cancelled and you'll start decelerating if you do nothing else. If you are not aware of that, it could take you by surprise and be dangerous. This is nowhere discussed in the manual that I could find.
 
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{disclaimer: I am not a mazda vehicle engineer nor do I play one on tv. Just my observations and opinion as a vehicle user}
I'm not keen on the idea of giving one acceleration instruction to the vehicle with the gas pedal and then moving into the passing lane where MRCC has a different acceleration instruction from the cruise set point and the systems rate of acceleration..
As soon as you move the accelerator pedal (even slightly) your telling the car "I got dis". You are overriding all of the i-active safety systems (MRCC, smart braking, etc) at once. The same holds true if the "system" falsely senses an obstacle (or truly senses but YOU the driver decides it's not a factor) and begins with it's BRAKE BRAKE BRAKE displays and alarms and eventually applying the brakes for you. When those situations occur (and they do/will from time to time) simply pushing slightly on the accelerator when needed is to me the best compromise to blending the car's autonomous systems and my manual control. YMMV.

My suggestions were based on you not liking the "lag in timing". Pressing the gas pedal solves the timing issue. now it's exactly when you want ...
I just don't like the lag in the timing of that acceleration and not knowing the precise point when it will occur. Cancel-coast-resume in old school mode is simple and works for me.
In your scenario of coming up on slower traffic and "pressing cancel/foot-feeding/resume" while waiting for a spot in the left lane to open up seems counter intuitive to your desire to "keep your eyes on the road". A couple of button pushes, dividing your attention between following distance and glancing in the mirror for the opening. Why not, in that scenario, let the MRCC worry about maintaining your following distance (one less thing for you to do) while you're figuring out the best slot to move into the left lane? Then when it's time to move, just push the gas pedal as your transitioning to the left lane as needed for traffic flow then release the pedal.

I suggest to spend some time getting used to the "driver assist" systems. They're far from perfect but I find they can be useful. Try using the gas pedal to "help" blend it. It's a learning curve.

Happy motoring and enjoy your new ride :)
 
{disclaimer: I am not a mazda vehicle engineer nor do I play one on tv. Just my observations and opinion as a vehicle user}

As soon as you move the accelerator pedal (even slightly) your telling the car "I got dis". You are overriding all of the i-active safety systems (MRCC, smart braking, etc) at once. The same holds true if the "system" falsely senses an obstacle (or truly senses but YOU the driver decides it's not a factor) and begins with it's BRAKE BRAKE BRAKE displays and alarms and eventually applying the brakes for you. When those situations occur (and they do/will from time to time) simply pushing slightly on the accelerator when needed is to me the best compromise to blending the car's autonomous systems and my manual control. YMMV.

My suggestions were based on you not liking the "lag in timing". Pressing the gas pedal solves the timing issue. now it's exactly when you want ...

In your scenario of coming up on slower traffic and "pressing cancel/foot-feeding/resume" while waiting for a spot in the left lane to open up seems counter intuitive to your desire to "keep your eyes on the road". A couple of button pushes, dividing your attention between following distance and glancing in the mirror for the opening. Why not, in that scenario, let the MRCC worry about maintaining your following distance (one less thing for you to do) while you're figuring out the best slot to move into the left lane? Then when it's time to move, just push the gas pedal as your transitioning to the left lane as needed for traffic flow then release the pedal.

I suggest to spend some time getting used to the "driver assist" systems. They're far from perfect but I find they can be useful. Try using the gas pedal to "help" blend it. It's a learning curve.

Happy motoring and enjoy your new ride :)
That's a partially useful answer which doesn't require a Mazda engineer. Somebody engineer-like probably wrote the user manual so that guy might not be much help anyway.

I just jumped out (again) on a nearby country road to try what you say to the extent I could without trailing somebody below the set point. I did find that manually accelerating past the MRCC set point is not a cancel function so it is not entirely a "you got this". As with old school cruise, if you finish your acceleleration past the set point then ease off the gas and decelerate back to the set point the cruise kicks back in.

In old school cruise I don't have to take my eyes off the road, but I won't bother you with another tedioius procedure. My thumb knows where the buttons are, at least in my prior vehicle. I'll get there pretty quick with this one. Situationally, sometimes I'll just cancel and give it the gas and not reset until I'm back in the right lane at the desired speed which isn't much different than what you describe.

I'll have to test what you say in a passing situation some time with the MRCC cruising below the set point. I may like it. I would not attempt to test whether emergency braking is overridden. 😮

I suggest to spend some time getting used to the "driver assist" systems. They're far from perfect but I find they can be useful.
Of course. But before experimenting on the road I like to have some idea of what to expect before trying something. The user manual is usually the place to start for that. This one is frequently useless. What you describe is nowhere to be found. See, I've teased out of a few folks here what should be in the user manual, your procedure still to be confirmed. I thank you all for that and maybe somebody else learned something in the process. I've got the door locks down pat now, MRCC pending that test, the security systems question is pending, and I'm sure there will be more questions as I work through the rest of the rest of the system functions with manual (ugh!) in hand then hands on the wheel.
 
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For my part, when I'm driving with my wife and she says, "Oh, look at that!," my stock response is, "I'm driving here."
Hijacking a bit here, but....
You hit it right on the head.
My wife does that constantly when I'm driving, and it makes me crazy.
She also overreacts to everything she sees when I'm driving, and will scream out loud "lookout", at which point I freak out looking for whatever it is she reacted to.
99% of the time, it's nothing, but it puts me on edge.
I'm actually a worse driver with her in the car because she causes most of my distractions.
 
Hijacking a bit here, but....
You hit it right on the head.
My wife does that constantly when I'm driving, and it makes me crazy.
She also overreacts to everything she sees when I'm driving, and will scream out loud "lookout", at which point I freak out looking for whatever it is she reacted to.
99% of the time, it's nothing, but it puts me on edge.
I'm actually a worse driver with her in the car because she causes most of my distractions.
Yeah, I know that "look out" thing. And I'm definitely a better driver driving solo.
 
I will add that one of the benefits of MRCC is the ability for the car to react while you're distracted, even slightly. It's a given that the guy in front of you or in the next lane over will come into your lane and slow down at the exact millisecond when you take your eyes off the road to grab a drink or switch a radio setting. While regular cruise control would require you to react by tapping the brake or hitting cancel, with MRCC it's a non-issue.
 
I will add that one of the benefits of MRCC is the ability for the car to react while you're distracted, even slightly. It's a given that the guy in front of you or in the next lane over will come into your lane and slow down at the exact millisecond when you take your eyes off the road to grab a drink or switch a radio setting. While regular cruise control would require you to react by tapping the brake or hitting cancel, with MRCC it's a non-issue.
Conversely, it could lead to a false sense of security, complacency, and inattentiveness. These systems are not foolproof--dirt, fog, snow, ice, or maybe light hitting in a certain way on radars or cameras can throw these system off. A Tesla driver found that a white semi-trailer against a white sky might be lethal if you rely on the system. He's not Elon's only dead customer. I can't remember if it was Mazda or another make that had a system slam on the brakes when a plastic grocery bag blew by. In a way we are all beta testers in live action for these systems to be refined over many billions of miles for the true autonomous era, which by the way is going to be a long time coming.

That said, I have more testing to do to see if I prefer MRCC after some good imput here and preliminary testing. But under no circumstance would I expect this system to be foolproof, nor any of the automated safety systems. Driving habits should not change. Blind spot detector is the one feature I most wanted. I'll still be taking a peak over my shoulder.

Jeez, I'm reading people can't get their door locks working in the way they expect, and a door lock never killed anybody as far I know.
 
{disclaimer: I am not a mazda vehicle engineer nor do I play one on tv. Just my observations and opinion as a vehicle user}



In your scenario of coming up on slower traffic and "pressing cancel/foot-feeding/resume" while waiting for a spot in the left lane to open up seems counter intuitive to your desire to "keep your eyes on the road". A couple of button pushes, dividing your attention between following distance and glancing in the mirror for the opening. Why not, in that scenario, let the MRCC worry about maintaining your following distance (one less thing for you to do) while you're figuring out the best slot to move into the left lane? Then when it's time to move, just push the gas pedal as your transitioning to the left lane as needed for traffic flow then release the pedal.

I suggest to spend some time getting used to the "driver assist" systems. They're far from perfect but I find they can be useful. Try using the gas pedal to "help" blend it. It's a learning curve.

Happy motoring and enjoy your new ride :)
I couldn’t have said it better myself. I do not see any relevance in using regular cruise control anymore. And in many cases where drivers actually use regular cruise control is most likely because they are not familiar with MRCC.
 
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