Honda Makes Motorcycle Talk To Oncoming Cars 146
An anonymous reader writes "The system generates warnings to riders and drivers of other vehicles by continuous exchange of positioning data from satellite GPS sources. This is particularly relevant as road users approach intersections, alerting them to other vehicles that are potentially on a collision course, allowing avoidance manoeuvres."
Interesting idea (Score:1)
Re:Interesting idea (Score:5, Insightful)
Re:Interesting idea (Score:5, Insightful)
Exactly. As a rider myself I would be wary of such a system. I'd worry that it would split my concentration and that I wouldn't be as focused on every curb cut and side street as a potential threat.
On the other hand, I wouldn't mind it if oncoming cars were alerted to my presence before they come flying out of a side street (or merge into my lane on the highway if possible).
Re: (Score:3, Insightful)
>I wouldn't be as focused on every curb cut and side street as a potential threat.
That is exactly was airline pilot said when TCAS (Traffic Collision Avoidance System) was mandated. Today, most of them would feel naked flying without it.
It just another tool to be integrated into your scan and could prove to be a life saving feature when approaching a blind intersection on an unlit country road at night.
Re:Interesting idea (Score:5, Insightful)
Something like this MAY have helped when I got collected by a 4WD (truck) with a bullbar last year while riding home from work. Here I was on a bright red sports bike, headlights on, stopped at an intersection behind a row of cars. BAM, right in to the back of me and pushed me into the back of the car in front like a pinball.
He swore he didn't see me. Granted, he was DUI, but a little alert telling him that he was approaching something at 60kph that was going to break when he hit it would have been useful. And less painful. For me, anyway.
Re: (Score:3, Insightful)
If he was so drunk he didn't see stopped cars in front of him, what makes you think ANYTHING else would have gotten his attention?
Re: (Score:2)
He was apparently sober enough to do a runner :/
My guess is that he saw the cars but completely misjudged the distances involved, especially with a bike as the tail reference point. If that was the case then a system that alerted him that there was something coming up would have had some remote possibility of preventing the accident.
Re: (Score:2)
If he was so drunk he didn't see stopped cars in front of him, what makes you think ANYTHING else would have gotten his attention?
Maybe it wouldn't have, but this problem is a frequent one for more than drunk drivers. I've heard of plenty of cases where semi drivers forgot the truck in front of them and decided to pull a little further forward crushing the bike in front of them that they could no longer see over their hood. In fact, this problem is so common most motorcycle safety courses specifically instruct riders how to deal with it.
Not that a system like this would necessarily work as a solution, just that you can't discount the
Re: (Score:2, Insightful)
Re: (Score:2)
Like you, I don't care if I have it or not, but I certainly don't mind others being alerted to my approach. However, with the way drivers ignore basic traffic laws and markings, I don't expect this to provide much more than a little passing help to those who already pay some attention. As a rider, the real problem I have is with silly (and extremely dangerous) little details they miss. For example, just today, I was almost sideswiped (well, I saw it coming before the driver made the move and was out of th
Use the existing alert system (Score:2)
I think what you need is to perform whatever operation it is all of the other motorcyclists seem to use that cranks their engine noise into the 110+ dB range. That will alert motorists on side streets, as well as residents in a three-block radius, and make certain that any passing runners can hear it over their headphones.
(As a runner myself, I have no difficulty telling when there are motorcycles coming up.)
Re: (Score:2)
It depends on the bike.
You can run a sport bike up to red line and it makes a ton of noise but its high pitched. You as a runner will hear it but the guy in the car might not.
The reason that Harleys are "loud" (really any cruiser, not just Harleys) is that their exhaust note is low pitched. It might not actually be louder than the sport bike but the sound carries and penetrates like the bass notes at a rock concert.
Personally, I do ride a Harley, but I don't run straight pipes or gun my engine in resident
Re: (Score:2)
It depends on the bike. You can run a sport bike up to red line and it makes a ton of noise but its high pitched. You as a runner will hear it but the guy in the car might not.
C'mon. This is Slashdot. We can make pipes to alter the pitch of anything to be loud and lower pitched with a little physics.
The reason that Harleys are "loud" (really any cruiser, not just Harleys) is that their exhaust note is low pitched.
Well, the harley is a special case since they intentionally run cylinders out of synch to create a "distinctive" noise but for just volume they are no different than any other engine. Cruisers and touring bikes have lower RPMs for their displacement and so have a deeper sound with the same pipes, as compared to sport bikes, but anything you put stock harley pipes on would be loud bec
Re: (Score:2)
Personally, I do ride a Harley, but I don't run straight pipes or gun my engine in residential neighborhoods.
Thank you for that. I've had more than a few motorcyclists deliberately gun their engines at me when I'm out for a run or cycling. I know that it's just that I remember the ones who do and forget all the ones who don't, so I try to keep a charitable disposition.
A Better Idea... (Score:2, Insightful)
...would just be to equip our motorcycles with RPG launchers for those idiot cagers who pull out in front of us. They'll only do it once.
Re: (Score:2)
I slow down for idiots like you, and when you pass me and cut in front of me to show me what's up, I flash my brights to give you a taste of your own medecine.
Re: (Score:2, Insightful)
i would think that scratches in the clearcoat or maybe a chip will be enough to make most people back off.
Re: (Score:1)
Re: (Score:2)
Re: (Score:2)
Yes, it's interesting theoretically, but in practice, I agree with others it's not going to work. Accuracy is inadequate: GPS in my car occasionally puts me on the wrong road, for goodness' sake. It's particularly bad in cities with tall buildings. Also, as pointed out elsewhere, false positives alone will make it deadly.
Fixed that for you..
"All clear a head"
SPLAT!
Re: (Score:3, Informative)
Re: (Score:2)
Re: (Score:2)
Re: (Score:3, Funny)
Yea just what I need when cornering on my bike.
"Sir, you realise if you go 1 more meter to you left you are road kill, sir can i warn you about the truck you are about to hit. CAR on the left pulling out. AHHHHH You are going down the middle of the road!!! we are surrounded, we are all going to die. AHHH! oh please noooo I don't want to die."
Re: (Score:2)
Re: (Score:2)
This could be real useful in general. Cars could tell each other what speed they where doing, what roads they where on "for avoiding traffic jams". Weather info, gas prices....
Seems like a good use for ZigBee.
Re: (Score:2)
Bad enough the police have radar without my car "helpfully" announcing my speed to them as I pass.
Re: (Score:2)
Simple enough to fix. Just have it report the locations where you couldn't go the speed limit.
The idea would be to show where there are traffic jams.
Re: (Score:2)
This is the start of cars driving themselves. There was recently a
Link to original article at Honda (Score:5, Informative)
"ahhhhhh.... (Score:3, Funny)
...please dont hit me!"
Vehicle spam (Score:1)
The real trick will be to figure out the algorithm so that impostor signals can be sent in the appropriate number and at the appropriate time such that the warning messages sound like a jingle.
Re: (Score:2)
The difficulty is (Score:1)
Still, once that's overcome (maybe it has been already), it should be pretty useful.
good for safety? many cars pull out in front of MC (Score:4, Informative)
This could be very good for the safety of motorcyclists if widely deployed. Many motorcycle accidents involve cars pulling out in front of motorcycles and the car driver saying that they didn't see the motorcycle.
My only concern is for privacy. The broadcast message should not include the VIN or any other unique identifier that could be used for tracking.
More at the Honda Site [hondanews.eu]. It seems to use a Car-to-Car [car-to-car.org] protocol that is in development.
All this kit though looks like it would add significant cost to a motorcycle. :(
-molo
Re: (Score:2)
Re:good for safety? many cars pull out in front of (Score:3, Interesting)
Looking at the Car-to-car site, it says it is based on 802.11 networking with something like wireless mesh routing. This means that they will have Wifi-like MAC addresses, which means cars will be uniquely identifiable and thus, trackable. :(
-molo
Re: (Score:3, Insightful)
...cars will be uniquely identifiable and thus, trackable. :(
I'm curious to how one would track vehicles to avoid collisions without, um, tracking vehicles.
Re: (Score:2)
You only need to use an identifier for a short period of time. The solution would be to randomize the mac address when you start the car. But that won't happen.
-molo
Re: (Score:2)
Not with the data already digitized in bulk and available to anyone with a radio receiver.
-molo
Re: wtf subject-length limit (Score:3, Funny)
GPS> "Motorcycle coming around bend in 3, 2, 1. Bonus points available !!"
I can see problems with this... (Score:1)
Re: (Score:1)
Re: (Score:2)
That's what proper following distance is for... didn't you pay attention in driver ed? If you keep the right amount of following distance, it would prevent said scenario.
How exactly will maintaining the correct following distance (call it A) between myself and the car I'm following prevent an accident with the car following me at 0.25A when I slam on my brakes?
Re: (Score:2)
The point is people don't.
Re: (Score:2)
Right. Arionhawk can follow me around and give the other drivers little slips of paper saying "You need to take drivers' ed" apparently, because I could be a perfectly good driver and still get hit because sumdumass wasn't driving safely. (My apologies to sumdumass [slashdot.org], I'm just using you as an example to make my point...)
Re: (Score:2)
Of course, that last bit would probably solve the problem on its own so I guess we can discount it as an option.
The real scoop (Score:3, Interesting)
The article link goes to an ad-plastered blog that tells you nothing more than the summary.
Honda made some thing that uses GPS to figure out when you're going to meet another vehicle, and then uses technology from the Intelligent Car Initiative (European Commission) to wirelessly transfer info between vehicles in the 5.9GHz range. It appears to use ad-hoc and repeater-type infrastructure, although the stuff I found is a little unclear on the ad-hoc.
The car driver gets some kind of warning, although it's unclear exactly what. The motorcycle driver is wearing a HUD that gives him a visual and audio warning. It's clever, but I find the whole CAR 2 CAR project (which this is part of) to be much more interesting.
Some real links:
http://www.hondanews.eu/en/index.pmode/modul [hondanews.eu]|detail|0|1010,DEFAULT|21|text|1/index.pmode
http://www.car-to-car.org/fileadmin/gfx/inhalte/IP-08-1240_EN.pdf [car-to-car.org]
Re: (Score:2)
Ill tell you this. The idea of a HUD sounds really cool and futuristic, but Id rather not have anything in my field of vision when I'm riding.
I might be willing to deal with an audio warning, but I don't want anything in my field of vision when I'm riding. My life (and sometimes other peoples lives) depends on it.
Re: (Score:2)
Thanks for noticing. I guess I put too much faith in ./'s parser.
Article [hondanews.eu]
It would seem to my (Score:2)
the best way to do this is have vehicles emit a low powered, low range signal that other vehicles and detect.
Wire the sound to the speaker nearest the location of the vehicle broadcasting.
Have the tone volume correlate to overall speed, and differential speed.
So that motorcycle zipping through traffic would be louder then one 'pacing' you.
Have it off when traveling under 20MPH.
Re: (Score:2)
no way.
have it cranked up to 150db when going under 20mph. I typically am attacked by careless drivers who are stopped or going under 20 mph.
I'm going down the road, they wait until I'm 120 feet away and then pull out trying to kill me. I want their eardrums to pop and bleed if they start moving from a stop when a motorcycle is within 500 feet of them.
90% of the problems with cars is at intersections with them stopped waiting for traffic, not on the highway.
Attention: Motorcycle Rider (Score:4, Funny)
It should warn when the motorcyclist is doing something asinine, which many in my state seem to do.
<kitt-voice>
Michael, you are not wearing a helmet.
Michael, perhaps driving between rows of cars is not the best method of saving time?
Michael, do you know what "yield" means?
Michael, zooming down the highway at 80mph isn't very safe.
Michael, watch out for that dangerous inters - *Connection severed*
</kitt-voice>
Re:Attention: Motorcycle Rider (Score:4, Insightful)
I'll grant you three of five, but "lane splitting" (legal in California under a large range of circumstances) really IS the best method of getting around Southern California. It doesn't add to the danger, if done reasonably, and the time savings are enormous. I've cut some trip times in half that way (90 min by car to 45 min on the bike), without speeding.
As far as 80 MPH, there are times and places on the highways where riding less than that is more dangerous because you are exposed to a "rear-ender" by a driver who cannot see a motorcycle that is right in front of him. A better line might be to say that exceeding the pace of traffic so much that you have to constantly change lanes isn't very safe.
Re:Attention: Motorcycle Rider (Score:4, Insightful)
It may indeed be faster, but it sure as hell isn't safe. Riding on a motorcycle is hazardous enough. When you're "lane splitting", all it takes is one car changing lanes or pulling over to the side of his lane, or another driver opening his car door to put you in the ER.
How many times have you seen morning drivers open their car door in stopped traffic to dump out their coffee? Now how would you like to find out what happens when an object moving 40 mph (you) collides with a stationary object (car door)?
Re:Attention: Motorcycle Rider (Score:4, Interesting)
"reasonably" means doing it when traffic is slow enough that lane changing is hard for the cages (cars/SUVs/pickup trucks), and still giving yourself enough time to see the potential change and avoid it. You learn to watch the faces of the drivers in the mirrors and you can see their head movements to give you information about their intent (it's not like anyone signals). It also means no splitting at 80 when they're doing 15 (yes, I have seen the bikes that do it, but that doesn't make it "reasonable", although it is sometimes "evolution in action").
You also learn to watch out for situations that create "holes" in traffic, particularly when it is slowing or speeding up, and avoid being between the hole and someone looking to fill it. In fact, the situations when being between a cage and a gap when NOT lane splitting concern me more than when I'm splitting because the cages' freedom of movement provides more opportunity for them to try to kill me.
The real danger to motorcyclists in stop-and-go traffic is that the driver behind almost never actually sees you and will (nearly always) stop just before his bumper hits the car ahead of him, regardless of the presence of the motorcycle between. We lose a few riders, including law enforcement officers on their "work" bikes, to that every year in Southern California.
Re: (Score:2)
(I am also a rider)
It's a calculated risk... you know, like you do every day when you pull out into traffic in ANY vehicle. Just because you're in a car, doesn't mean you're not at risk from precisely the same things.
I live in a state where lane splitting is illegal, more's the pity... but it's rarely a requirement here. When I was in England a few years ago on a motorbike though, it was definitely a great way to get through often standstill traffic, quite legal... and generally relatively safe.
First, there
Re: (Score:2)
Heh... and you think the average cager actually checks his mirrors before opening his door? Or check blind spots before changing lanes?
Doesn't happen... at least not in my experience. I realize that you're right... but as insinuated many times before; a person is smart... people are stupid.
Re: (Score:3, Insightful)
pfft. 80 mph is the standard in Southern California. Welcome to the real world bub.
Not a Luddite, but not a believer either (Score:5, Insightful)
Re:Not a Luddite, but not a believer either (Score:5, Funny)
The only way I have been able to preserve my life and retain all my original body parts is by assuming they're all actively trying to kill me, and protect myself accordingly.
Hence, the AK-47, body armor, and the grenade launcher mounted to the bike.
Re:Not a Luddite, but not a believer either (Score:5, Insightful)
Actually many cyclists wear body armor. my motorcycle leathers have it built in. I have kevlar and composite plastic in the back and elbows and shoulders. it's comfortable and from a friend that was ran off the road by some blond idiot in a escalade it saves your life when you wipe out at 30mph and eat a tree with your back.
"oops I did not see you, sorry!" is their favorite line.
Re: (Score:2)
"oops I did not see you, sorry!" is their favorite line.
<sarcasm>Oh, I bet that's comforting</sarcasm>
Wait, you said it was a blond (I will assume female), didn't you? Depending on how sorry she is, it might be comforting after all.
Re: (Score:2)
I don't know about you, but in my universe most motorcycles in proximity to roads fail to approach the speed of sound.
Re: (Score:2)
Regardless of all that, I'd sooner rely on my skills in the saddle as opposed to hoping that expensive clothing is going to save me -- because I know that when it comes right down to it, it won't.
Re: (Score:2)
Actually, I rely on both... having had one relatively minor road-rash once in my life and found that it hurts like an SOB having your leg brillo-padded in the hospital to get the grit out.
I wear a full-face helmet, gloves, a jacket and riding overpants... oh, and boots. ATGATT [urbandictionary.com]. I know from experience that the padding in good quality gear will protect you from the relatively minor impact you suffer when low-siding a bike... or even rolling off the hood of a car that just pulled out in front of you. I also kn
Re: (Score:2)
Here in Rightpondia, we have a word for it, "smidsy", which stands for "Sorry Mate I Didn't See You".
Unfortunately, I have had two friends killed in the last 6 months by car drivers doing a smidsy. The first one, the car driver died too. He failed to stop at a stop sign, and drove straight out into the path of my friend, who was a big guy on a big bike. The most recent one, just a few weeks ago, was three 18 year olds in a people carrier (tr. US: minivan) suddenly pulling out of a junction without looking.
Re: (Score:2)
Re: (Score:2)
In fact, the "warning" is more likely to distract even those few who might have seen you, by leading them to look inside the car, rather than outside.
This is a REALLY, REALLY bad idea.
I've been riding for a few decades myself and have used exactly the same "system". When they "try" to kill me, I'm already a step ahead and out of the way.
Re: (Score:3, Insightful)
unfortunately people don't see other cars either. i ride/drive *every* vehicle i own as if everyone else doesn't see me.
of course it's human nature... i've made some boneheaded driving mistakes in my time too. i remember one road trip my gf fell asleep bear-hugging my right arm. drove an hour and a half home working the stick shift with my left hand. =P
Re: (Score:3, Insightful)
unfortunately people don't see other cars either. i ride/drive *every* vehicle i own as if everyone else doesn't see me.
Agreed. USAA Magazine once ran a column where they said that at any given time, there is better than a 50 percent chance that the other driver is drunk, stoned, fatigued, or otherwise incapacitated or distracted.
As far as car drivers making mistakes, I have been on both sides. I pulled out in front of a bike once. Fortunately, he was not one of the 50 percent above, and all it did was piss him off. In this case, his headlight was not on, but it taught me to look, not just glance.
The flip side was that I had
Re: (Score:3, Insightful)
*nodding* that goes without saying. If you spend most of your time in the saddle, the habits stay with you.
Re: (Score:2)
Yes, it has nothing to do with bikers riding between traffic lines or other traffic infringements at 10 - 20 % above the speed limit...
* note you may not do this, but a large portion of riders do.
Re: (Score:2)
I often ride at 10% above the speed limit, however I never lane-split.
Why do I ride at 10% above the speed limit? There is usually more traffic in the left lane and there is merging traffic and the like. So I ride in the right lane.
If I was to ride the speed limit in the right lane, I'd be stuck in at least one car's blind spot at any one time. So I actively accelerate out of the blind spots.
Other reasons why speed limits need to be exceeded include lorries! If part of their load falls off, I'm dead. If the
Re: (Score:2)
I do it in a limited, restrained fashion: only when traffic is stopped, only when it's safe to do so, and never at an excessive speed. I am disgusted by other cyclists who abuse the fact that lane-splitting is neither legal nor illegal in most places by being unsafe about it and/or going too fast; they make life more difficult for the rest of us by making ALL of us look bad
Re: (Score:2)
Re: (Score:2)
I am not a motorcyclist myself, but if some idiot driver is going to look right through a motorcyclist or bicycle user what on earth makes Honda think they are going to hear some computer tell them they are approaching. There are enough idiot drivers out there that don't see cars approaching and just pull out.
Personally I am in favour of taking away the driving license for life of any driver who knocks a motorcyclist or cyclist down, and their excuse is they didn't see them.
Re: (Score:2)
You forgot to close your comment with "Get off my lawn". :p
Re: (Score:2)
That's fine, to each his own -- you can remain stuck in traffic and struggling to get 30MPG, and I'll cruise right past you while I'm getting 45 to 50MPG. ;-)
Re: (Score:2)
Point well taken, since I also go running on a regular basis. One might question the wisdom of running down the street with a big stick in your hand, though -- the cops might get the wrong idea. :-/
Oh Great... (Score:1, Interesting)
Another buzzer to drown out with the stereo.
(I'm not necessarily against the idea, but the interface on these ideas is usually 'a blinking light and a buzzer'. By the time you've sorted out what this light means, you are already in the accident.
distraction? (Score:2)
Of course using this system will distract the driver from using the cues provided by the natural environment (which are many)... thus it will have to not only provide a benefit, but provide enough benefit to overcome what is lost.
Let alone what happens if someone's GPS is malfunctioning or even that a lot of people aren't going to have this system installed...
Highway cloverleaves, bridges, tunnels.... (Score:1)
Ripe for havoc (Score:2)
Imagine some psychopath who programs the GPS announcer to lie about its position, telling nearby cars that it's approaching them at 100 mph?
In the best case, this leads to people ignoring the collision warning beeps from their cars. In the worst case, someone is develops a car that automatically performs some evasive maneuver based on that data.
My Honda VFR motorcycle already does this (Score:3, Funny)
Re:My Honda VFR motorcycle already does this (Score:5, Insightful)
and it's useless. Loud pipes are for annoying people not for any other use.
it's simple physics... if the loud noise is exiting the BACK of the bike throgh a directed horn facing and traveling away from you, how the hell will the bimbo in the BMW that is 500 feet ahead of you going to hear it? she wont and she does not. even the big motorcycle safety organizations refuse the claims about lout pipes save lives.
Loud pipes are simply for being a public ass. No other reason, stop trying to justify it and just admit you like annoying people.
Re: (Score:2, Informative)
I used to think like this as well - Until I was rear-ended. Twice. The second time took out my whisper-quiet exhaust, so I put in one a bit louder. Not hate-the-neighbors loud, but louder. I've noticed people being more aware of me - Not in the "glaring" aware, but generally people leave some more room now. And I haven't been rear-ended since (i know, i know, correlation is not causation)
And I don't think sound is quite that directional... It's not like loud bikes are completely silent followed by a h
Wandering the roads. Sad. Trying to talk to cars. (Score:2)
Hi, how are you todwrooom... *sigh*
I think they need to do buildings first. (Score:4, Interesting)
I think they need to do buildings first. Maybe not to ward off on-coming traffic, but for triangulation. If buildings like the towns city hall were to pipe up and give out their latitude/longitude, it shouldn't be too hard to remove the unreliable gps from the equation. The more buildings of significance were to participate the easier it would be to create maps based on that town/city. Then cars can locate themselves and others. If 75% of cars have local positioning system, then it becomes mandatory.
Security would be a nightmare though.
Re: (Score:2)
Yeah... thats true. That or the roadside reflectors would the method of cheaply making autonomous vehicles. Want to drive yourself? Then go to the driving track.
Honda Makes Motorcycle Talk To Oncoming Cars (Score:2)
... in a stark room with hot lights. Honda was later quoted as saying "He was a tough one, but eventually we got him talking."
Right. (Score:2)
Re: (Score:2)
Most people would ignore it.
I watch people look up, acknowledge that someone is coming at them with very little time to react, and then pull out in front of them and hope they have good brakes. A lot of people just don't care or understand the implications of the choice they could have just made.
Its no deterrent to a lot of people that their actions could be the direct cause of an accident, as long as its someone else involved.
Not new. (Score:4, Informative)
Glider pilots developed a low cost collision avoidance system called FLARM.
The small-size, low-cost, low-power device FLARM broadcasts its own position and speed vector (as obtained with an integrated GPS) over a license-free ISM band radio transmission. At the same time it listens to other devices based on the same standard. Intelligent motion prediction algorithms predict short-term conflicts and warn the pilot accordingly by acoustical and visual means. FLARM incorporates a high-precision WAAS 16-channel GPS receiver and an integrated low-power radio transceiver.
See www.FLARM.com
Hmmm (Score:4, Funny)
Motorcycle: Hey you! Car! Look out for me, I'm right over here!!
Car: Wha..? I can't see you. Who the hell is this?
Motorcycle: I'm right here! Can't you see me?!
Car: I think I can.... oh I can s... *BLAM*
Useful for aircraft collision avoidance (Score:2)
All aircraft should transmit their position and velocity to all other aircraft in the vicinity. It then doesn't take much computing power for the autopilot computer to calculate the minor course correction that would be needed to avoid the other aircraft (or even its wake vortices). It would make mid-air collisions a thing of the past (at least, while autopilot is turned on. All bets are off if a human's at the yoke.)
Re: (Score:2)
Re: (Score:2)
Too many stupid drivers (Score:2)
I'm not a biker (yet), but I have to agree with a lot of the posts here. The biggest problem is people just don't pay attention. I'll be the first to admit, I push the limits a lot in my car, but I've never had a problem seeing either type of cyclist on the road. The only time there's any visual difficulty at all is when it's dark and one headlamp/tail-lamp is a bit difficult to use as a point of reference for distance. But that's never proved to be a big problem. I've also had other drivers pull out right
Re: (Score:2)
Those are great once a car is up to the intersection and can see the on coming motorcycle. I don't have one but I have found that riding with my high beams on during the day improves drivers ability to see me coming. I wouldn't mind drivers getting a warning before they even reach the intersection.