rxgs2011

My new 2015 RX450h is equiped with the Optional Radar Cruise control. Prior to buying the car I had lots of questions about this option, but found there really wasn't enough information on what it did and how it worked. Now that I have owned the car for 4 months, and used the cruise control a lot, I thought I would start a post explaining exactly the way I have found the system to work. For those of you who want to know.
First, how you turn it on.
If the cruise control is OFF, pressing in on the end of the cruise control stick turns it on and by default the Radar feature is ON! Every time! To turn off the radar feature permanently you have to reach way up under the dash board, where you would never look, to find a little button to press. It is next to a button that initializes the Tire Pressure Sensing system. The button is really out of the way and is intended to be pressed very rarely, and only when you can stop the car open the door, lay upside down, and look up under the dash to find the button with a flashlight. Assuming you don't want to permanently disable the radar feature, it will turn on every time you turn on the cruise control. You do however have an option to change the cruise control back to a conventional "Speed Hold" kind of cruise control when you have first turned it on. On cars equiped with radar cruise control the cruise control lever has one additional function. The lever moves forward toward the floor opposite from the "Cancel" function. The stick is marked "MODE" with a small arrow. If you press the lever forward and hold it for a few seconds, the cruise control mode will change. You will know which mode it's in by the dashboard indicator. Both Radar and conventional icons are green and next to each other on the dash. They only light up when the cruise control is ON. Before you set the cruise control to activate it, you can toggle the mode back and forth between Radar ON and Radar OFF. After you set the speed the first time you are stuck in the mode you selected, until the next time you turn the cruise control on from the off mode. When the cruise control is turned ON the little display in the middle of the dash will change from any display it had been on and display the words "Radar Ready". If you change the mode to conventional speed hold mode, the "Radar Ready" words disappear and the display area will be blank like in a standard RX. If the cruise control is turned on and in the Radar mode, you can press the small extra button on the face of the steering wheel that selects the following distance. This button is not present on a standard RX without Radar cruise control. If you press the distance set button before the cruise control speed set button is pressed, a small icon appears in the display area resembling a car with 3 white bars above it. This icon appears below the area where "Radar Ready" was displayed. The car icon and white bars indicate the default distance setting, which is the longest distance. If you press the distance button it will cause the white bars to disappear one by one, until only one bar is seen. This is the nearest distance. The closest the radar will allow you to follow another car is about 3 or 4 car lengths. I have found the closest setting is a bit scary in heavier traffic. I found I was reaching to press the brake pedal if the car ahead was going much slower than I was. Lets say 20MPH slower. Under normal conditions the closest setting is the most common one I use since other drivers will almost always invade the space between me and the car ahead of me if I use the far setting. It's just a bit too far. The typical aggressive drivers in my area feel 2 car lengths is plenty for them to invade my space. The two bar distance setting is actually the best, but in heavier traffic other drivers invading your space becomes annoying as the cruise control constantly slows you down to let the offending driver in your space. Once you have set the distance the display will blank out again after a couple of seconds and just display "Radar Ready". When you actually SET the speed to launch cruise control, then the car distance display appears again and stays displayed. If no car is ahead of you, or is too far away, the display shows only one car, YOU and the one, two or three bars indicating the distance set. When the cruise control radar does see a car ahead, then a second car symbol appears above the bars. This symbol appears and disappears as cars enter it's view. More on Radar Cruise Control later!

rxgs2011

Adding to what I already posted in the 1st installment, here are my observations on the operation of the Lexus Radar Cruise Control. It works great! The first pleasant surprise was, that if you have the Radar Cruise Control option, the drivers dashboard display area doesn't just sit there blank with the little word "set" in the bottom corner. When you have Radar Cruise Control the speed you set is displayed above the word set. Why this can't work this way without the radar option I don't know. It should be possible on any car with cruise control, but you will only see the actual set speed when you have the radar feature. It's very nice because you can see how much you have stepped up or down the set speed when you press the lever up or down to adjust it. As when you are driving down a highway and the speed changes from 65MPH to 55MPH. You can begin pressing the cruise lever down one MPH at a time and stop when the display reads 55. The car will then slow down to that speed. Another big surprise with the radar option is that the system has access to the brakes. Yes! The cruise control will apply the brakes if the car doesn't slow down fast enough, or if you set a speed dramatically slower than you are presently going. In my RX450h hybrid, the cruise control uses mostly the regenerative braking mildly applied if I reduce the set speed. It also uses the regenerative braking if I am rapidly approaching a slower vehicle. The cruise control acts like it is actually driving the car. It will apply the brakes somewhat aggressively, as you would yourself if someone does something stupid in front of you, or you come upon much slower traffic. Typically in normal traffic, the speed transitions up and down without you even noticing it's changing. It is such a pleasure to drive with this Radar doing all the work. I drove from Cape Cod to Washington DC on Rt 95 with the cruise control on almost the whole time. Even in the cluttered, everybody changing lanes, kind of road traffic you find in the northeast of the US I could leave the cruise control engaged and just steer. The cruise control will slow you down all the way to 25MPH, then there is a quick "Beep-Beep-Beep" and the cruise control releases braking to you. The system stays ON, but not set, as if you had pressed the "Cancel" button. There is also a more FRANTIC "BEEP-BEEP-BEEP-BEEP-BEEP" that is triggered if you are rapidly approaching a very slow car or someone enters your lane and seriously reduces the following distance. If the cruise control has to execute, what you would consider, a PANIC braking event, at speeds above 25MPH it even pumps the brakes noticably, to quickly slow the car down, but not cause the cars behind you to rear end you. I have not been behind my car yet to see if the brake lights come on during these aggressive braking episodes. It is quite amazing. The car is driving for you. It works very well. It's even smart enough to recognize a car who butts in front of you to change lanes, but is going faster than you. If that happens it ignores the reduced distance and does not over react. Yes the distance is invaded, but it doesn't panic. It does slow you down if the offending car is going slower than you, then it brakes. So the radar must be sensing the speed of the closure rate with the car ahead. If the distance is increasing with the car ahead of you, then it lets things continue without braking. If the distance between the car ahead is shrinking, then braking immediately begins. Braking begins mildly in most situations with nice control. I have had instances where I was driving 65MPH with the cruise control set and over a period of a few minutes the cruise control took me gently down to 30MPH following heavier traffic without even touching the brakes or turning off the cruise control. I've had the cruise control then take me right back up to 65 as traffic starts moving. The only abrupt situation is when a rude driver changes lanes to get to an exit, slows down dramatically in front of me then slips off the exit clearing my lane. If the cruise control had to slow down the car significantly, then once the road clears, it efforts to get you back up to the set speed quickly. A 30MPH to 65MPH speed up is performed a little more rapidly than I would do if I had my foot on the gas pedal. In the Hybrid with the CVT it's not bad. In a RX350 with a 6 or 8 speed automatic, I would assume there might be some downshifting in this situation. Somebody out there with a RX350 can comment on Radar cruise control - resume speed response. Speaking a little more about the low speed limits of Radar Cruise control, 25 MPH seems to be when the Radar system hands things over to the driver. In addition 28MPH is the lowest limit on the speed you can SET on the cruise control. I haven't tried for a TOP speed setting. Another BIG surprise was that the radar system used with the cruise control is in fact ALWAYS ON! What that means is that it is always watching out for you. It sees the proximity problems ahead. If you are barreling ahead straight toward a slow or stopped car, with the cruise control OFF, the warning system alerts you. You get a "BEEP-BEEP-BEEP-BEEP" and a dashboard warning message that says "BRAKE!" I discovered this quite by accident one day when a stupid driver cut in front of me to make a right turn. He was slowing down and I had to aggressively brake. Before I even noticed how slow he was going and got my foot on the brake the car was BEEPING and the word "BRAKE" was flashing in front of me. When I did slam on the brakes they reacted fast. I think I experienced the Pre-Collision braking system. It is as if the brakes went on full. I slowed down fast! I was impressed. I also have the Heads-Up-Display and the cruise control messages appear there too. So you see the word {BRAKE} displayed in a white square that alternates Black letters on White - White Letters on Black, with beeping until the warning is suspended or you come to a stop. I can't say enough good things about the Radar Cruise Control. I want it on every car from now on.

charley95

Paragraphs please.

rxgs2011

Didn't mean to offend or make things difficult. I'll work on my structure. I hope you at least read my post and enjoyed it.

Any positive feedback for me?
I had to work New Years day and sat at my computer trying to do something constructive.

Happy New Year!

litzdog911

Don't worry about the lack of paragraphs. I fully agree with your observations and really enjoy the Radar Cruise Control on our 2015 RX450h.

Marqevans

I almost feel glad I don't have radar cruise. Sounds way to complicated.

TheSnowman

This is pretty much how I feel about the Cruise Control on my 2010 RX350 Sports Luxury here in Australia

It is awesome and I use it everywhere, you can be on a city street and checking out the ladies while it takes care of any braking required

And for Marqevans even if you don't like the concept, your next car will probably have something similar as worldwide there are move to legislate to make advanced emergency braking system (AEBS) or autonomous emergency braking (AEB) compulsory in all new vehicles.

That works to slow you down just as the Radar Cruise Control does, probably better with new technology since my car was built.

Thanks for the post rxgs2011 hey, BTW, brake lights do come ON

rxgs2011

Thanks.
I'm an electrical engineer not an english major. At least I put in periods and spelled most of the words right.

rxgs2011

Thanks Snowman for answering my question about the brake lights. I thought they must come on during the braking.

JDR76

I too have radar cruise on my RX350 and love it. It's very simple to use - just set your speed and distance setting and you're off!

iginoc

Thank you, a very accurate description of the ACC.

I may add that it is possibile to enable/disable the ACC through the menu available through the pushbutton on the right side of the steering.

However, I have to say that here in Europe is very difficult to make a good use of the ACC. Even if you set at the minimum the distance from the car preceeding you, there is always some bad*ss that feel compulsory to put his car just in the middle. And the ACC reacts braking abruptly you car. Very annoying. Then the aforementioned guy is out of the way, and the ACC accelerates violently your car, burning unnecessarily a lot of fuel. Perhaps the worse case is driving on France, as I did last summer with my RX450h. Apparently, the below descripted behavior is taught in French driving schools, since it is common to all, I say to every French driver I met on the highways: you're going minding on your own business, maintaining your cruising speed which happens to correspond to the limits (130 kmh on the highways) . Before, at about 3 car lengths, there is another car that goes at the same speed. There comes a guy (or a gal, it's the same) on the left, that goes to 133 kmh. He/she overtakes you very very slowly, but just after it, wham, he/she cuts and puts his/her car no more than 5 meters away ... then slows down to 125 kmh.You can imagine how reacts your Lexus ACC ... verrry frustrating

JamLoo2019

Thanks for these posts. I just bought an RX & was actually trying to figure out how to turn off the adaptive feature (which I found in another post). Thanks for the info on the car beeping even when not in cruise control - that’s a very useful feature! And thanks for taking the time to write the post - paragraphs or not
;-).