mmarshall

Well, a hybrid's electric motor(s) can produce a lot of torque, but usually at very low RPMs. An electric motor (theoretically) has max torque at zero RPM, with a sharp drop-off as RPMs increase. At the kind of cruise-RPMs he was talking about, the system, even with the gas engine operating in tandem, would not likely have the kind of torque he is talking about to cause that kind of acceleration. Or, if so, I don't see how.

Allen K

iTrader: (4)

When you're not expecting the car to accelerate, any acceleration is going to feel excessive. All of the conventional cruise control systems that I've used have been aggressive when it comes to resuming the cruise speed, I don't see why the adaptive cruise control would be any different

pbm317

Agree, even standard cruise controls will drop a gear or two to accelerate. For large speed changes I generally cancel and accelerate/slow down on my own and then set it again.

corradoMR2

How does a Lexus vehicle behave if someone suddenly cuts you off but is moving faster than you? I.e. how does the Radar Cruise and/or PCS respond if at all?

I'm hoping it's smart enough to know the car ahead is going faster so that the Lexus does not suddenly slam the brakes and cause the car behind you to rear-end you.

Nextourer

With the Prius' DRCC, it is aggressive on the acceleration and will accelerate hard if the difference between the set speed and the current speed is great so what you experience was "normal" operation.

You are correct in identifying the problem (my dad does the same thing as he's not used to DRCC) so he's pushing up on the RES/+, expecting the car to increase in speed but ends up setting the DRCC speed to something much higher than intended.


As long as the vehicle is going faster than you, the car will not respond. It's very accurate with minute differences in speed. I've had that scenario happen where I prepared for it to brake (checked the rear view mirror, foot hovering on the accelerator if necessary) but it didn't and tailed the car in front. In reality, the car in front was maybe doing a few km/h faster than me and slowly pulling ahead but visually, it doesn't look like it as we can process those minute differences.

Also, it will not slam on the brakes. It'll sound an alarm (fast repeating beeps) and flash something on the multi-information display (usually "BRAKE!" or in DRCC mode, it'll flash the entire icon with the car and distance bars). It can be aggressive on the brakes (e.g. car in front suddenly slows down due to a construction zone or traffic volume) but never a full out panic-type brake.

corradoMR2

Was hoping this was the case since I never had (nor felt the need to have) these "driver aids" and the NX I ordered has them all. Awesome feedback thanks

bitkahuna

iTrader: (20)

thanks for the clear confirmation of my experience. as has been said, NOW that i know what was going on, it won't be a problem. i do expect my next vehicle to have adaptive cruise though as i find the speed up / slow down on interstates to be annoying.

RXSF

I got the PCS/Adaptive CC on my RXh because it sounds like a cool tech option to have. In reality, it doesn't really work out that well. The distance, even when set to the closest, is still too large and cars are constantly coming into the lane, thereby causing the CC to brake and increase even more distance.

Generally, it does a pretty good job at following the speed of the car in front, even if it is a motorcycle. Problem is that if there is a steep turn, it sometimes gets confused and thinks that the car in the next lane away from the curve, is in its own lane, thereby hesitating/braking as well.

Also, since it cannot see ahead past the car directly in front, it cannot react until the car in front reacts. Sitting high, I can see when traffic begins to slow down and I can release the gas pedal early. With the CC, it cannot take advantage of this additional information and then it has to brake suddenly, thus reducing MPG. On a similar note, it does not accelerate or decelerate with much grace.

I realize that this feature is really meant for long stretches of mindless driving and not busy city freeway driving but this tech still needs a lot of improvement.

pbm317

While I agree the system in the RXh leaves a lot to be desired, I wouldn't use it as a knock against all such systems.

Each one is so different from automaker to automaker in terms of execution/calibration/effectiveness. And that really depends on which supplier they're working with.

The system in the latest Chrysler vehicles and Hyundai/Kia's is quite effective, and available at a price that is fairly competitive. The top of the industry right now is definitely the Mercedes S-Class.

I've been able to use the Chrysler and Hyundai/Kia system to effectively and safely navigate Los Angeles stop and go traffic .

Since the one for the RX was developed quite some time ago, I'm hoping that the full-stop capable system in the NX is the next generation of the feature and in line with other systems currently on the market.

RXSF

Yeah, I realize the RX system is outdated but I brought it up because the OP was talking about the Prius system which is the same as the one in the RX. Cant wait to get my hands on the Mercedes distronic system.

PatsSoxfan

I can tell you that the radar/adaptive cruise on my wife's RX450h is not very smooth at all. The system on the 2008 LS460L that I owned worked considerably better than that on the RX. However, the radar cruise in combination with the Distronic Plus on my 2014 S550 is fantastic and I believe it is the best in the industry.

chikoo

maybe it was going fast in an attempt to get you your 2 car lengths gap that you ordered in your cruise menu.

mmarshall

That kind of programming probably wouldn't work in some places. In the L.A. and D.C. areas, for instance, traffic is so dense, and the roads so crammed full (especially at peak morning/evening rush) that, even with traffic moving, the system couldn't keep that kind of length between cars. it would be virtually impossible. Somebody would constantly be cutting in and taking up the open space.

chikoo

You are talking about the other end of the spectrum.

In a highway situation, where I have ordered 2 car length distance and a max speed of 85 mph while I was doing 40mph, the result would be the car speeding up all the way to 85mph or getting a 2 car length distance, whichever occurs first.

lobuxracer

iTrader: (2)

Sounds a lot like the F-111 pilots who didn't trust their TFR (terrain following radar) back in the early days of the 111 being operational. They would see a mountain in front them and would grab the stick instinctively and plow right into the mountain. It took a lot of training to get them over the fear factor. That said, holding the cruise in the + position will definitely cause unintended consequences even without adaptive cruise, AMHIK.

I usually click the + instead of holding it. Each click is worth 1 km/hour, so two clicks is ~ 1mph. Works like magic.