Honda CR-V Owners Club Forums banner
1 - 20 of 20 Posts

·
Registered
Joined
·
15 Posts
Discussion Starter · #1 ·
Kinda hard to figure out what to title this... But after my trip to work on Thursday morning and what happened I got wondering what pre-collision braking might do in this type of situation...

Was traveling on a 2 lane highway and got to a point where you come up a slight incline to a bridge and then the road declines a bit on the other side. Nothing more than a few degrees but enough that as your coming to the bridge you can't see the traffic ahead of you. As I was going over the bridge, i realized that in the left travel lane there were headlights coming towards me. Fortunately for me there was lighter than usual traffic that morning and I wasn't in the left lane as usual passing the cars that were still trying to get up to speed from the on-ramp a mile plus back. A previous generation Corolla went flying by at a good rate of speed.

My curiosity is what would the pre-collision braking do in this situation? I know that if you're traveling toward a stopped or slower object in front of you (car, building, blade of grass, etc) it will slow you down or stop you completely depending on speed, but what in the event an object is coming toward you?

I would think it should try to slow you down/stop you but in the case of an oncoming vehicle, wouldn't that make your damage worse vs you maintaining the same speed or going faster? I did terrible in physics, so it's probably a simple answer but it's been too long and I hated those classes anyway...

Just curious if anyone has any ideas what it's "programmed" to do, or theories on what it might do...
 

·
Registered
Joined
·
207 Posts
Lots of situations that can reduce the system effectiveness (weather, roadway conditions, vehicle limitations--see the list in the manual), but:

The system starts monitoring the roadway ahead when your vehicle speed is about
3 mph (5 km/h) and there is a vehicle in front of you.
The radar sensor is
in the front grille.
The CMBSTM activates when:
● The speed difference between your vehicle and a vehicle or pedestrian detected in
front of you becomes about 3 mph (5 km/h) and over with a chance of a collision.
● Your vehicle speed is about 62 mph (100 km/h) or less and the system
determines there is a chance of a collision with:
- Vehicles detected in front of you that are stationary, oncoming, or traveling in
your same direction.
- A pedestrian who is detected in front of you.
● Your vehicle speed is above 62 mph (100 km/h), and the system determines
there is a chance of a collision with a vehicle detected in front of you traveling
in your same direction.
 

·
Super Moderator
2017 CRV Touring - Pearl White w Black Interior
Joined
·
7,511 Posts
I agree with Jim256.

The only cautions I would add are as follows:

Honda Sensing is a bit iffy with regard to detecting pedestrians.. so don't count on it... always be on the lookout.

Honda Sensing and safety actions driven by it rely on the sensors (millimeter radar on the front, Camera on the front, side lane detect sensors) to make decisions. They are NOT infallible... but they will be as good or better then the driver ~90% of the time. These sensors are also effectively "line of sight" and as such.. the human eye is still a better sensor as it can detect subtleties the sensors will miss.. like light appearing to be just over the horizon of a hill, or shadows based prediction.

You have to keep in mind, current generation HondaSensing is good, but it is NOT Level2 or higher autonomous capable. Understand it's limits, and as the driver always pretend it is not there and be aware of your surroundings.
 

·
Registered
Joined
·
343 Posts
Kinda hard to figure out what to title this... But after my trip to work on Thursday morning and what happened I got wondering what pre-collision braking might do in this type of situation...

Was traveling on a 2 lane highway and got to a point where you come up a slight incline to a bridge and then the road declines a bit on the other side. Nothing more than a few degrees but enough that as your coming to the bridge you can't see the traffic ahead of you. As I was going over the bridge, i realized that in the left travel lane there were headlights coming towards me. Fortunately for me there was lighter than usual traffic that morning and I wasn't in the left lane as usual passing the cars that were still trying to get up to speed from the on-ramp a mile plus back. A previous generation Corolla went flying by at a good rate of speed.

My curiosity is what would the pre-collision braking do in this situation? I know that if you're traveling toward a stopped or slower object in front of you (car, building, blade of grass, etc) it will slow you down or stop you completely depending on speed, but what in the event an object is coming toward you?

I would think it should try to slow you down/stop you but in the case of an oncoming vehicle, wouldn't that make your damage worse vs you maintaining the same speed or going faster? I did terrible in physics, so it's probably a simple answer but it's been too long and I hated those classes anyway...

Just curious if anyone has any ideas what it's "programmed" to do, or theories on what it might do...
I don't know about you but in the scenario you laid out I wouldn't want the braking trying to stop me. I'd want full power to get out of the way. To answer your question - if you did slow down the impact would be less but not sure it would really matter. It would still be pretty bad.
 

·
Registered
Joined
·
207 Posts
FYI, from the manual, too:

When the CMBSTM is activated, it will continue to
operate even if the accelerator pedal is partially
depressed. However, it will be canceled if the
accelerator pedal is deeply depressed.

I also have a Lexus with the anti-collision braking, and the Lexus also cancels it with rapid steering movement, the thinking is that the driver has taken control. Honda does not mention steering but logically if you're hitting the gas you are steering somewhere else.
 

·
Registered
Joined
·
118 Posts
The radar sensor is
in the front grille.
Where is this located? (A picture would help.) My system doesn't seem to work and in the middle of the grille, there's a blank plate. It seems to me that this is a strange place for a blank plate. If there isn't supposed to be something there, it would look better if it was grille and not blank.

I guess I'm concerned that the factory left something off my car. 2019 CR-V EX-L w/500 miles.
 

·
Registered
Joined
·
2,024 Posts
If you are going one way at 50MPH and the other car is also going 50MPH straight at you, it would be like hitting the other car at 100MPH if it were stopped.

Any reduction in that combined speed is welcome, but on a practical basis, the range of the radar is too short to make much difference. It's more made to slow you down if the car in front of you is going slower than you expected, not fix a catastrophic head-on collision.
 

·
Registered
Joined
·
2,024 Posts
Where is this located? (A picture would help.) My system doesn't seem to work and in the middle of the grille, there's a blank plate. It seems to me that this is a strange place for a blank plate. If there isn't supposed to be something there, it would look better if it was grille and not blank.

I guess I'm concerned that the factory left something off my car. 2019 CR-V EX-L w/500 miles.
That blank plate has the radar behind it.
 

·
Super Moderator
2017 CRV Touring - Pearl White w Black Interior
Joined
·
7,511 Posts
Where is this located? (A picture would help.) My system doesn't seem to work and in the middle of the grille, there's a blank plate. It seems to me that this is a strange place for a blank plate. If there isn't supposed to be something there, it would look better if it was grille and not blank.

I guess I'm concerned that the factory left something off my car. 2019 CR-V EX-L w/500 miles.
Behind the black plastic flat surface immediately under the Honda Logo on the grille is the millimeter emitter/receiver assembly. If you stand to the side and shine a flashlight in there, you can see the back of the assembly as well as parts of the bracket set that retain it in "true". If you look up the part on line, you can see what it looks like, as well as all the other parts required to fully install it, or repair it. https://www.hondapartsdirect.com/oem-parts/honda-radar-assembly-milliwave-36803tlba04?c=az0xJnE9MzY4MDMtVExCLUEwMw==&origin=pla&gclid=EAIaIQobChMIsNXLzYGx5AIVv__jBx3Vnw8_EAYYASABEgLOIPD_BwE

The reason it is located behind a flat plastic facing is to insure no distortions or reflections in the millimeter radar. that said... some owners have reported ice collecting on that flat surface during bad winter weather and that ice WILL distort or block the radar signals.
 

·
Registered
Joined
·
11 Posts
Living in New England, I experience problems with the radar being obstructed when driving during periods of heavy rain or any type of snow or ice storm. During moderate rain or light snow, it's not generally a problem. Heavy snow and ice, however, will cause the radar and safety features (lane-keeping assist, road departure mitigation, automatic braking) will not work. During these conditions, common sense says you shouldn't drive using cruise control or depend on your vehicle to be a safer driver than you. However, we all know that common sense isn't so common these days! :)
 

·
Registered
Joined
·
69 Posts
some owners have reported ice collecting on that flat surface during bad winter weather and that ice WILL distort or block the radar signals.
I'll report that too. I don't know why they don't use the ambient temperature read out and heat that plate when the temp drops below freezing. Its in bad weather you want that front radar working over time!
 

·
Registered
Joined
·
69 Posts
From my experience, I have a 2015 CR-V touring, I have never had the system brake because there was oncoming traffic in another lane. As people have said, its line of sight. If the other car is not directly in front the emitted radar signal will reflect off a car to the side at an angle and not return to the receiver.

My big beef with the Honda system is when you approach another car it slams on the brakes when the set trail distance is reached, instead of slowly slowing down. Then my wife looks at me like I am not paying attention.
 

·
Super Moderator
2017 CRV Touring - Pearl White w Black Interior
Joined
·
7,511 Posts
I thought millimeter radar was not effected much by weather.
Some owners have reported issues when snow or ice accumulated on the front plastic surface in front of the emitter/receiver.

I believe them... precisely because frozen water can indeed interfere with transmission and reception of the radar pulses, even though I have personally not experienced an issue (I live in California, and have never driven through snow and ice to date in my CRV.

I'm not sure how to go about adding a heating element to prevent ice buildup.... and still leave the transmision/reception abilities unhampered. But I am sure that Honda engineers can find a way, and likely will in future generation system deployments. :)
 

·
Super Moderator
2017 CRV Touring - Pearl White w Black Interior
Joined
·
7,511 Posts
My big beef with the Honda system is when you approach another car it slams on the brakes when the set trail distance is reached, instead of slowly slowing down. Then my wife looks at me like I am not paying attention.
While I agree that the system could be a bit more nuanced in how it activates... I also understand that once it begins braking.. it has already determined that you are too close and not braking as the driver, so it intervenes very frimly.. and that definitely gets the drivers attention.. which I believe is by design. In other words.. it IS doing it's job.. which is to avoid a collision. In this sense... I think your wife was correct. :)

Would you prefer the system had an audio nanny-mode... where it begins griping at you first, then berating you for inaction, ... before taking over and hitting the brakes? :p
 

·
Read Only
Joined
·
217 Posts
Some owners have reported issues when snow or ice accumulated on the front plastic surface in front of the emitter/receiver.

I believe them... precisely because frozen water can indeed interfere with transmission and reception of the radar pulses, even though I have personally not experienced an issue (I live in California, and have never driven through snow and ice to date in my CRV.

I'm not sure how to go about adding a heating element to prevent ice buildup.... and still leave the transmision/reception abilities unhampered. But I am sure that Honda engineers can find a way, and likely will in future generation system deployments. :)
A better solution is turn off the feature(s) in inclement weather, drive according to conditions and, most of all, pay attention. That's how so many of us reached old age without all these "safety" features.
 

·
Registered
Joined
·
35 Posts
While I agree that the system could be a bit more nuanced in how it activates... I also understand that once it begins braking.. it has already determined that you are too close and not braking as the driver, so it intervenes very frimly.. and that definitely gets the drivers attention.. which I believe is by design. In other words.. it IS doing it's job.. which is to avoid a collision. In this sense... I think your wife was correct. :)

Would you prefer the system had an audio nanny-mode... where it begins griping at you first, then berating you for inaction, ... before taking over and hitting the brakes? :p
My big beef with this system (on my 2019 CRV EX-L) is the number of false alarms I get. On several occasions, I've been driving down the road with NOBODY in front of me and suddenly the dashboard flashes STOP and it activates. I can see it being confused on curves when traffic in the other direction may seem to be coming toward me, but that's not always the case. Maybe I need to play with the settings...
 

·
Super Moderator
2017 CRV Touring - Pearl White w Black Interior
Joined
·
7,511 Posts
My big beef with this system (on my 2019 CRV EX-L) is the number of false alarms I get. On several occasions, I've been driving down the road with NOBODY in front of me and suddenly the dashboard flashes STOP and it activates. I can see it being confused on curves when traffic in the other direction may seem to be coming toward me, but that's not always the case. Maybe I need to play with the settings...
I'm sure it varies by location and road conditions and the possibility of sensor artifacts vs the landscape.

Personally, as an urban driver, I have only had one false positive in the 2 and half years I have owned my 2017. And that was in town about 35 mph, on a straight paved road, and it was very definitely a reflection of bright sunlight off the back window of the vehicle about 100 feet in front of me. It blinded me as well for a second, so it was pretty obvious what the sensing systems were reacting to. Good experience though.. because it taught me that the vehicle will indeed brake to avoid a perceived hazard, even at lower in town speeds.

Better a false positive though, then a complete miss, so in this regard I think HondaSensing is tuned on the conservative side, and I am OK with that.
 
1 - 20 of 20 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top