Dynamic Radar Cruise Control
06-06-14, 03:48 PM
#1
Dynamic Radar Cruise Control
My 2014 GS450h is equipped with the Pre-Collision System and Dynamic Radar Cruise Control. I've had the car for about 2 weeks now, and am beginning to get a better feel for the capabilities, and limitations, of the system. The dynamic cruise generally works smoothly and responsively in light to moderate traffic on LA freeways. It will take the car to a dead stop in slow traffic and resume when traffic starts moving again. Where you need to be careful is in traffic where there is aggressive lane changing.
The system works so well that you can forget it's engaged. If you do, and then begin to exit the freeway, you may be in for a bit more excitement. Today I experienced my first yellow alert from the system when I moved on to an exit ramp where traffic had slowed. The display flashed yellow and beeped to alert. I braked aggressively and avoided a collision. Two drivers in back of me steered onto the shoulder to avoid hitting me.
The operative word in the feature is "Cruise". This is a driving support system, it's not an autonomous vehicle system that can cope with any driving maneuver.
The system works so well that you can forget it's engaged. If you do, and then begin to exit the freeway, you may be in for a bit more excitement. Today I experienced my first yellow alert from the system when I moved on to an exit ramp where traffic had slowed. The display flashed yellow and beeped to alert. I braked aggressively and avoided a collision. Two drivers in back of me steered onto the shoulder to avoid hitting me.
The operative word in the feature is "Cruise". This is a driving support system, it's not an autonomous vehicle system that can cope with any driving maneuver.
Last edited by georgee01; 06-06-14 at 04:30 PM.
06-06-14, 05:48 PM
#2
Watch yourself going from highway speeds to those in small towns. If you're not careful, you can find yourself going the 35mph speed limit an appropriate distance behind another law-abiding motorist. Then, when that car turns into the 7-11, you will be "riding the beast" since you're only going 35 but DRCC still has a set speed of 65mph and the road is clear ahead. Makes for an interesting story to tell the local deputy! The remedy is to constantly set new DRCC set point speeds at or slightly above the posted speed limit as soon as the limits change. That way, no unpleasant surprises...
Last edited by williakz; 06-06-14 at 05:51 PM.
06-07-14, 05:09 AM
#3
Instructor
But I though as soon as you step on the brakes the system should be cancelled just like regular cruise control? Am I missing something here? Everytime I take an exit ramp I always signal and tap the brakes before taking the exit.
06-07-14, 06:41 AM
#4
Not talking about freeways, although a similar situation can occur there as well (see below). Think of a country highway with 55mph or 65mph posted speed limit (PSL). Between towns, you're merrily cruising along at 70mph via DRCC. Then you come up on a bluehair doing exactly the PSL. DRCC slows you to her speed at either a long, medium, or short distance separation (default is long). As the highway heads into town, PSLs go to 50, 45, 40, and finally 30mph. You're still in distance regulation, so she's setting the speed and DRCC is maintaining distance. BUT the system's set speed is STILL 70mph (your open road cruising speed). IF she pulls out of your way at State and Main, you're going to be going for a Ride (capital "R" ride) when DRCC switches from distance regulation to speed regulation mode with your car going 30mph and DRCC in control and wanting to go 70mph.
This same thing often occurs on the freeway (especially when short distance selected). As traffic gets heavier, you'll go into distance regulation and there will be a speed gap between DRCC set point and actual speed. When the slow poke finally gets out of your lane (clearing the short lookahead distance), DRCC will rapidly accelerate the vehicle to bring actual speed up to its setpoint. Depending on the size of the speed gap and how long you've been in distance regulation mode, the sudden acceleration can come as a real surprise.
I always try to keep my speed gaps to 5mph in order to minimize both the shock and the potential consequences of the eventual DRCC catch-up sprint. Hope this helps.
This same thing often occurs on the freeway (especially when short distance selected). As traffic gets heavier, you'll go into distance regulation and there will be a speed gap between DRCC set point and actual speed. When the slow poke finally gets out of your lane (clearing the short lookahead distance), DRCC will rapidly accelerate the vehicle to bring actual speed up to its setpoint. Depending on the size of the speed gap and how long you've been in distance regulation mode, the sudden acceleration can come as a real surprise.
I always try to keep my speed gaps to 5mph in order to minimize both the shock and the potential consequences of the eventual DRCC catch-up sprint. Hope this helps.
Last edited by williakz; 06-07-14 at 04:10 PM.
06-07-14, 03:49 PM
#5
A light tap on the brakes does not always cause the system to disengage, it has to be a bit more pressure on the pedal. The surest way to cancel DRCC is a quick pull forward on the control lever.
I have started to manually adjust the set speed as traffic slows, because, as noted, the acceleration can be a bit startling when the road ahead suddenly becomes clear.
I have started to manually adjust the set speed as traffic slows, because, as noted, the acceleration can be a bit startling when the road ahead suddenly becomes clear.
07-01-14, 09:15 PM
#6
My 2014 GS450h is equipped with the Pre-Collision System and Dynamic Radar Cruise Control. I've had the car for about 2 weeks now, and am beginning to get a better feel for the capabilities, and limitations, of the system. The dynamic cruise generally works smoothly and responsively in light to moderate traffic on LA freeways. It will take the car to a dead stop in slow traffic and resume when traffic starts moving again.
My 2013 GS350 has the DRCC, and it disengages between 25 and 30 mph, and does not reengage unless I hit the resume. Our Volvo S80 with DRCC performs as you describe, resuming if your stop is less than 3 sec.
07-02-14, 12:54 AM
#7
Please confirm about taking the car to dead stop and resuming. Maybe 2014 is different...
My 2013 GS350 has the DRCC, and it disengages between 25 and 30 mph, and does not reengage unless I hit the resume. Our Volvo S80 with DRCC performs as you describe, resuming if your stop is less than 3 sec.
My 2013 GS350 has the DRCC, and it disengages between 25 and 30 mph, and does not reengage unless I hit the resume. Our Volvo S80 with DRCC performs as you describe, resuming if your stop is less than 3 sec.
We're also missing the Rear cross traffic, HD traffic, Siri, power trunk...... Mostly software update.
I would never buy their first year models again.
Last edited by onexcite; 07-02-14 at 12:58 AM.
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07-02-14, 12:57 AM
#8
Yes, yet another reason never to buy a car as first batch. wait at least a year.
07-07-14, 02:57 PM
#9
In stop and go traffic, I'm not sure this functionality is very useful. It does a pretty good job in slow, 20-30 mph traffic as long as you need the set point reasonable to prevent rapid acceleration if the lane ahead clears.
07-07-14, 03:51 PM
#10
I have noticed my traffic updates are off compared to google maps.
07-07-14, 03:56 PM
#11
The system works so well that you can forget it's engaged. If you do, and then begin to exit the freeway, you may be in for a bit more excitement. Today I experienced my first yellow alert from the system when I moved on to an exit ramp where traffic had slowed. The display flashed yellow and beeped to alert. I braked aggressively and avoided a collision. Two drivers in back of me steered onto the shoulder to avoid hitting me.
It sounds like you were expecting the car to make a smooth transition from cruising to exiting off the ramp with only limited space. Talking to someone who just bought an X5, he said the braking on it's ACC is very aggressive, and he changes lanes to get behind someone to slow down the car and he said it's very sudden, which makes sense because the car can't tell the difference between people coming to an abrupt stop verses people just slowing down slightly.
07-07-14, 06:04 PM
#12
07-07-14, 06:49 PM
#13
if you have a problem you should call SiriusXM and talk to them, you just need to call their 800# and give them your phone number and they will find your account unless the dealer screwed up and didn't register your car correctly.
07-07-14, 08:23 PM
#14
DRCC can apply limited brake force. When it calculates that the closing rate is too great for it to maintain a safe following distance, it gets your attention. Although I didn't test it, I believe that if collision was imminent, PCS would light up the dash red and apply full brake force.
07-07-14, 08:31 PM
#15
Ah I think you mean NavTraffic. I was thinking what the hell is HD Traffic, maybe it's better than what I have since NavTraffic seems a bit slow to update.
if you have a problem you should call SiriusXM and talk to them, you just need to call their 800# and give them your phone number and they will find your account unless the dealer screwed up and didn't register your car correctly.
if you have a problem you should call SiriusXM and talk to them, you just need to call their 800# and give them your phone number and they will find your account unless the dealer screwed up and didn't register your car correctly.
HD Radio data services were introduced on some 2014 Lexus models (IS, CT, GX) and will come to the GS for 2015 as part of the next generation Enform. HD data services are subscription free.