Radar Cruise...amazing stuff!
06-13-14, 05:52 PM
#1
Lead Lap
Thread Starter
Radar Cruise...amazing stuff!
I have to say...the Radar Cruise worked better than I ever imagined today. Traffic was running 74+ when everything came to a quick stop ahead of me. I was set for medium (2 bar) distance and the car decelerated and braked down to 35 MPH and NEVER got any closer to the car ahead of me. I Never touched the brake, hovered my foot over the pedal. Traffic proceeded to speed up and the car accelerated back up to speed like nothing ever happened,
This will be one option that will be hard to be without in the future. I know Radar Cruise is not there for safety purposes, but it sure as heck does a good job of it. I also have PCS, and not sure how much that played into what happened today.
This will be one option that will be hard to be without in the future. I know Radar Cruise is not there for safety purposes, but it sure as heck does a good job of it. I also have PCS, and not sure how much that played into what happened today.
06-13-14, 08:20 PM
#3
Back in 2005 I test drove an Infiniti Q45 with radar cruise control. I was so impressed I swore I would never buy a new car without it. When I bought my 2007 LS there were no cars with PCS in any snowbelt state. The dealer looked as far south as Virginia and none were available. I was told Lexus felt that since the system wouldn't work in a snow storm or if the sensor was covered with snow or ice, they didn't send any program cars with that option to dealers in the snowbelt. So that is why I had to special order my car so that I could have it.
The system is amazing. I've had small motorcycles cut in front of me and it picks them right up. With regular cruise control you would only use it on a highway. I've actually used it on country roads where you have traffic moving at constantly varying speeds. It just keeps you at a same distance from the car in front of you.
It will shut off once you go below 25 MPH, but you get an audible and visual warning.
The system is amazing. I've had small motorcycles cut in front of me and it picks them right up. With regular cruise control you would only use it on a highway. I've actually used it on country roads where you have traffic moving at constantly varying speeds. It just keeps you at a same distance from the car in front of you.
It will shut off once you go below 25 MPH, but you get an audible and visual warning.
06-13-14, 08:20 PM
#4
Why don't you guys who think DRCC is the berries post some video of it in action on a freeway in moderate traffic? I've been looking at some videos of adaptive cruise by other makes. There's a beauty of some guy in a VW (YouTube "Golf MK7 ACC") who almost gets into 3 accidents in less than 15 minutes when people cut into his lane (I counted 10 cuts) because of the huge gap (following distance) the system requires. Here's a link to a paper examining adaptive cruise in general and recommending a non-linear gap in order to more closely approximate the real world. However, you need to study the graph on the first page VERY CAREFULLY. It shows typical Lexus-type system (linear), the recommended non-linear response, and then THE REAL WORLD. So post up some video of your cars under DRCC dealing with the real world.
Last edited by williakz; 06-13-14 at 09:43 PM.
06-13-14, 08:54 PM
#6
As background, here is some material I posted on DRCC shortly after I got my 2013 LS460 in February of 2013 and was able to put the system through its paces. Since then, BSM capability, now ubiquitous across many different makes and models, seems to give a lot of drivers new-found confidence to force the "gap" more than they ever dared to before when everything was purely visual. Cars are always jumping in front of me into gaps of less than two car lengths at speeds up to 60mph. Using the typical "2-second" DRCC rule, the minimum gap at 60mph would be 176ft or TEN CAR LENGTHS! Good luck keeping that gap free and clear at anything close to the set speed, DRCC!
General Comments:
Dynamic Radar Cruise Control definitely has a learning curve associated with it. It works best in the simplest situations and becomes progressively less useful as traffic density - and complexity - increases.
First, the system is quite a bit sloppier in speed regulation mode than I'm used to. My previous LS with "standard" cruise regulated speed to +/- just a few mph. DRCC is happy to let me go 5 to 7 mph over the set speed. That's a bit much if your set speed is already over the posted speed limit (PSL). That said, the system is quite responsive in distance regulation mode, braking almost exactly at the same time I would (so you don't feel panic that the system is sleeping) and applying the brakes firmly but not abruptly. Note that this version of DRCC will brake the car from whatever the set speed is all the way down to a full stop (say for the one red light in a small town along a two-lane highway). When this occurs, you must goose the accelerator just a tad to get DRCC back in action once the light turns green.
The system really fails in moderate to heavy freeway traffic because the separation distance between me and the car ahead is just too large. It encourages cars behind me to pass me on the right and jump into the two-to-three car length space in front of me. When they do, DRCC slows down to maintain its minimum separation and the next guy pulls the same routine and so on and so on. The way to get around this is to override DRCC's gap by closing it manually until conditions become slightly less congested. I should note that if Lexus shortened DRCC's "gap," the system would have to operate much quicker and braking and acceleration would necessarily become somewhat more noticeable, possibly to the point of annoyance.
You must always "tend" the system. If not, you can find yourself in some dicey situations. For example, you're on a 65mph PSL four-lane highway that slows to 55mph then 45mph then 40mph as it passes through a small town with several traffic lights (all green). Your set speed is 73mph and you're in distance regulation mode with the guy in front of you going at exactly the PSL at all times. Eventually you find yourself going 40mph behind him when he decides to move out of your lane so he can pull into the Burger Doodle. If you haven't been paying attention, you'll find yourself doing the PSL (40mph) with a 73mph set speed and an open road ahead. The car will take off like a banshee and you'll be the one screaming! Therefore, I always make sure I'm lowering (and raising) my set speeds as the PSLs go down (and up) even when I'm in distance regulation mode. So, no surprises. Note that this same effect can occur when you change lanes causing the mode to go from distance to speed regulation. You think you're just making an easy lane change out from behind a slowpoke, but the car sees open road and rapidly accelerates to reach its set speed. It is disconcerting to say the least. DRCC demands your attention! Probably it becomes second nature after a while, but I don't have the knack quite yet.
Specific Criticism:
The folks in the right lane are motoring along, as is their wont, at somewhat below the PSL. The folks, including me, in the left lane are zooming along at or above the PSL. The actual separation distance at 70-75mph in the left lane is NEVER more than THREE CAR LENGTHS. We have a stable system wherein the pokies are happy and the speedies, while never quite happy, are satisfied they are running as hot as possible. We have a Q-point!
UNTIL, that is, I push the fatal button and DRCC cracks open its gimlet eye, emits a low growl, and drools in anticipation of the havoc shortly to be visited on the hapless motorists of the interstate. I set speed to current with a downflick, up it by 5mph with a precise 0.75 second upflick, double-tap the distance separation button to short and WE'RE OFF!
But wait a minute. Why is the car slowing down? And how can I tell the guy behind me who's suddenly flashing his highs and beeping his horn that he just needs to hold his horses. DRCC will stop slowing in heavy traffic when it achieves a SEVEN or EIGHT CAR LENGTH gap in front of me. Oh, and how to let the pokes on my right now going faster than I am know that they are NOT to jump left into the huge gap DRCC is creating in front of their disbelieving eyes; no, they are to keep staring at the back of the truck they have been following for 25 miles! And then, when the pokes DO jump into the gap, causing me to slow again, is there anything at all I can say to the angry speedy behind me to keep him from cutting right into the space vacated by the pokes and then gunning it and cutting into my gap (raised middle finger and all), thereby causing me to slow again. The sinking feeling in the pit of my stomach is the realization that a new set of pokes and speedies are already moving into position for another round of the "DRCC Grand Slalom." Oh boy!
And this is what constitutes a state-of-the-art dynamic cruise control system? Sheesh...
General Comments:
Dynamic Radar Cruise Control definitely has a learning curve associated with it. It works best in the simplest situations and becomes progressively less useful as traffic density - and complexity - increases.
First, the system is quite a bit sloppier in speed regulation mode than I'm used to. My previous LS with "standard" cruise regulated speed to +/- just a few mph. DRCC is happy to let me go 5 to 7 mph over the set speed. That's a bit much if your set speed is already over the posted speed limit (PSL). That said, the system is quite responsive in distance regulation mode, braking almost exactly at the same time I would (so you don't feel panic that the system is sleeping) and applying the brakes firmly but not abruptly. Note that this version of DRCC will brake the car from whatever the set speed is all the way down to a full stop (say for the one red light in a small town along a two-lane highway). When this occurs, you must goose the accelerator just a tad to get DRCC back in action once the light turns green.
The system really fails in moderate to heavy freeway traffic because the separation distance between me and the car ahead is just too large. It encourages cars behind me to pass me on the right and jump into the two-to-three car length space in front of me. When they do, DRCC slows down to maintain its minimum separation and the next guy pulls the same routine and so on and so on. The way to get around this is to override DRCC's gap by closing it manually until conditions become slightly less congested. I should note that if Lexus shortened DRCC's "gap," the system would have to operate much quicker and braking and acceleration would necessarily become somewhat more noticeable, possibly to the point of annoyance.
You must always "tend" the system. If not, you can find yourself in some dicey situations. For example, you're on a 65mph PSL four-lane highway that slows to 55mph then 45mph then 40mph as it passes through a small town with several traffic lights (all green). Your set speed is 73mph and you're in distance regulation mode with the guy in front of you going at exactly the PSL at all times. Eventually you find yourself going 40mph behind him when he decides to move out of your lane so he can pull into the Burger Doodle. If you haven't been paying attention, you'll find yourself doing the PSL (40mph) with a 73mph set speed and an open road ahead. The car will take off like a banshee and you'll be the one screaming! Therefore, I always make sure I'm lowering (and raising) my set speeds as the PSLs go down (and up) even when I'm in distance regulation mode. So, no surprises. Note that this same effect can occur when you change lanes causing the mode to go from distance to speed regulation. You think you're just making an easy lane change out from behind a slowpoke, but the car sees open road and rapidly accelerates to reach its set speed. It is disconcerting to say the least. DRCC demands your attention! Probably it becomes second nature after a while, but I don't have the knack quite yet.
Specific Criticism:
The folks in the right lane are motoring along, as is their wont, at somewhat below the PSL. The folks, including me, in the left lane are zooming along at or above the PSL. The actual separation distance at 70-75mph in the left lane is NEVER more than THREE CAR LENGTHS. We have a stable system wherein the pokies are happy and the speedies, while never quite happy, are satisfied they are running as hot as possible. We have a Q-point!
UNTIL, that is, I push the fatal button and DRCC cracks open its gimlet eye, emits a low growl, and drools in anticipation of the havoc shortly to be visited on the hapless motorists of the interstate. I set speed to current with a downflick, up it by 5mph with a precise 0.75 second upflick, double-tap the distance separation button to short and WE'RE OFF!
But wait a minute. Why is the car slowing down? And how can I tell the guy behind me who's suddenly flashing his highs and beeping his horn that he just needs to hold his horses. DRCC will stop slowing in heavy traffic when it achieves a SEVEN or EIGHT CAR LENGTH gap in front of me. Oh, and how to let the pokes on my right now going faster than I am know that they are NOT to jump left into the huge gap DRCC is creating in front of their disbelieving eyes; no, they are to keep staring at the back of the truck they have been following for 25 miles! And then, when the pokes DO jump into the gap, causing me to slow again, is there anything at all I can say to the angry speedy behind me to keep him from cutting right into the space vacated by the pokes and then gunning it and cutting into my gap (raised middle finger and all), thereby causing me to slow again. The sinking feeling in the pit of my stomach is the realization that a new set of pokes and speedies are already moving into position for another round of the "DRCC Grand Slalom." Oh boy!
And this is what constitutes a state-of-the-art dynamic cruise control system? Sheesh...
06-14-14, 01:59 AM
#7
Complety agree with williakz however all the system is designed to do is aid the driver not replace him. An autonomous car would be critiziced for this system but nothing will ever beat human reactions, but it also won't replicate human errors.
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06-14-14, 08:23 AM
#9
There are many interesting articles (admittedly dense, technical, and math-y) on the principles of ACC that are worth checking out - easy to skip over the babble and still understand the conclusions. One of the more perceptive ones forecasts that gap distances can't realistically be decreased much below the "2-second" rule unless and until the majority of cars on the road can talk to each other in a co-operative ACC "cluster." They set up such a cluster model and were able to use 6-12ft gaps at speed. THAT's even a bit close for my tastes, but I've been there before in the 1970's on northbound I-75 heading out of Detroit on a Friday afternoon doing bumper-to-bumper 75mph.
Last edited by williakz; 06-14-14 at 08:33 AM.
06-14-14, 11:28 AM
#10
Lead Lap
06-14-14, 04:13 PM
#13
Then post video of "it just working." I've linked to video and articles that show the shortcomings of ACC in detail. Just post your own videos (or link to your YouTubes) showing how the system works. I'm perfectly willing to be convinced. The guy in Istanbul didn't quite do it for me...
06-14-14, 05:02 PM
#14
Lead Lap
Thread Starter
Then post video of "it just working." I've linked to video and articles that show the shortcomings of ACC in detail. Just post your own videos (or link to your YouTubes) showing how the system works. I'm perfectly willing to be convinced. The guy in Istanbul didn't quite do it for me...
Do you have it in your car?
06-14-14, 05:56 PM
#15
What? DRCC? See Post #6. If DashCam, that's also affirmative.
It's up to you guys to show the system "works" as you ditto'd. I've posted personal experience, technical articles, and video showing it does not. "Ditto" to "It works" does NOT constitute a rebuttal. If you disagree with one or more of the specifics in my critique of DRCC, please let me know where, how, and why you believe I was mistaken.
It's up to you guys to show the system "works" as you ditto'd. I've posted personal experience, technical articles, and video showing it does not. "Ditto" to "It works" does NOT constitute a rebuttal. If you disagree with one or more of the specifics in my critique of DRCC, please let me know where, how, and why you believe I was mistaken.