Radar Cruise uses engine braking?

[GoISU]

First off, I am a huge fan of the radar cruise feature. I have never had it on a vehicle previously and I believe it to be basically witchcraft.

Does anyone know if this system will use engine braking to slow the vehicle? It seems to slow down faster than if you were just to take your foot off the gas when it needs to create space. For example, when someone slides into your “gap” that the radar maintains the vehicle slows as if the brakes were applied but the taillights are not lit in the dash graphic. Also, there seems to be no sensation of braking (I have a bit of shimmy when brakes are applied lightly at speed).

Just curious if perhaps the system locks up the torque coverter to apply some engine braking when needed or some other type of witchcraft.

 

[OregonLC]

Don’t know, but I’m not a fan. It’s too subtle on the open road. I can be set at 75 and then I look down and I’ve been doing 65 behind another vehicle and haven’t sensed the slowdown. Easy to happen when on the widest follow setting and things are on your mind or you have a good read playing on audible. I wish it would beep or give some other indication other than the preceding vehicle symbol in the display. I’ve gone to using the old school manual cruise unless I’m in city traffic. Forces me to stay engaged and change lanes. It’s much more agressive at picking speed back up than when closing on a vehicle in the distance. I do agree that it will react more affirmatively when someone pulls in front or you click down 5 or 10 mph... and those increments are another annoyance; why not keep both modes at 1 mph adjustment?

 

[GoISU]

I have had the same thing happen, it’s pacing a vehicle I think is going my speed and I realize that I’m down 10mph for who knows how long.

 

[OregonLC]

I do believe that all of the ECU controlled autoboxes do have intelligence and will downshift/lockup to assist with speed control. Even the A750F in our 2004 100 will passively downshift on downhills when it senses speed increase and brake application with no throttle input.

I think the worst example of this was in the 2008 MDX that I briefly owned. It would always use engine braking even when coasting in traffic. Annoying. It felt like there was always drag on the vehicle. Honda did this for fuel econ as there is complete fuel cutoff when the throttle is closed and the rpm is above ~ 1,200. Hated that truck. The only redeeming quality was that I purchased it brand new and was able to sell it one year later for only a $3,000 hit! Last Honda product I will ever buy.

 

[SWUtah]

It uses the brakes and will wear your brakes out fast. I think there’s a way to turn the cruise off the radar cruise off and just use normal cruise

 

[Sandroad]

On a trip to Indiana today, I experimented a bit with the question of CC brake usage. When I manually turned off CC, the truck slows down reasonably quick, though there is some "coasting". When using radar CC, there were no times it needed to slow faster than it would have if I had just turned CC off, even when cutting in/out of slow truck traffic. I have no solid conclusions from this, but I'm convinced that for safety purposes and likely even regulatory purposes, Toyota would never design a system that applied the brakes of a vehicle for you without the brake lights coming on. That could be extremely dangerous to traffic behind you.

 

[Dan Higgins]

For my part, I love it. Mine (2016) clearly uses engine braking though it is subtle and that is good. It may not shift gears - that depends on how quickly you need to slow down. I use cruise control for 2 reasons. So my legs can relax and to help avoid a speeding ticket. I have also learned to "work it". For example, if I coming up behind a truck that I know is going slower, it displays a message that it has registered the truck in front and is monitoring its speed. If the truck is going slower than I want I try to look for an opportunity to move to the left hand lane and when I do the LC speeds back up. Heck, I did over 50 miles on I5 from Eugene to Portland last week with the cruise set at the speed limit +5 and I never touched the accelerator or the brake! That was ~40mins. When I am on single lane highways it ensures that I am not likely the fastest person on the road which helped this past week when I drove from Eugene Oregon over to the coast. I have twice had tickets on that highway for unconsciously slipping up to 65MPH when the limit is 55MPH.

 

[SWUtah]

 

[Dan Higgins]

I've used it for many thousands of miles (most of my 40K miles are on long freeway road trips and I use it whenever possible.) With 40K on my my rear brakes are still good. Changed my fronts at ~33K. Maybe that is fast but it is longer than I had with my LR4 and my LC weights 6500 much of the time. Certainly it uses the brakes if it needs to significantly slow down. But it doesn't feel like brakes when it is merely maintaining the speed of the vehicle in front. Maybe it does but it is very subtle. Feels to me more like just backing off the gas. Unless someone cuts in front of me and I need to quickly decelerate. But were that the case, I would be using my brakes anyway. Maybe it is always the brakes all the time. Gas, brake, gas, brake, etc. But, as I have said, I use it a lot and have not noticed any issues or extra wear on the brakes.

 

[LBridges]

A cut & paste from the '17 owner's manual:

"Example of deceleration cruising and follow-up cruising. When a preceding vehicle driving slower than the set speed appears

When a vehicle is detected running ahead of you, the system automatically decelerates your vehicle. When a greater reduction in vehicle speed is necessary, the system applies the brakes (the stop lights will come on at this time). ..."

 

[LALC]

Yeah, on my '16 it absolutely engine brakes while cruising unless there is an emergency where it will use the brakes.

 

[SWUtah]

question will it bring the LX to a complete stop like some collision control systems? Personally, I'm easy on brakes, normal is 60k miles. It's a good system just only seems worth while if your on a long straight section of interstate like I-70 through Kansas.

 

[LALC]

question will it bring the LX to a complete stop like some collision control systems? Personally, I'm easy on brakes, normal is 60k miles. It's a good system just only seems worth while if your on a long straight section of interstate like I-70 through Kansas.

The LC it does not. The system doesn't work below 28mph or something close to that so once you drop below it cuts off, warns you, and you have to take over.

 

[LALC]

question will it bring the LX to a complete stop like some collision control systems? Personally, I'm easy on brakes, normal is 60k miles. It's a good system just only seems worth while if your on a long straight section of interstate like I-70 through Kansas.

The LC it does not. The system doesn't work below 28mph or something close to that so once you drop below it cuts off, warns you, and you have to take over.

 

[LBridges]

Worth noting that the Radar Cruise Control is a different system from the Pre-Collision system (on the 2017 model anyway).

As mentioned by LALC the radar cruise control system kicks off around 25.

However, as a partial answer to SWUtah, the pre-collision system braking has different use cases. For the case where it brakes without user assistance, the speeds are between 7 and 110 mph for vehicles and 7-50mph for pedestrians. Where it assists (if it thinks you aren't braking hard enough) the speed where it might kick in is above 19mph. The manual notes that if one is in 4-lo the braking part of the system is disabled. I could not find a reference to determine if it will bring the vehicle to a complete stop, or if it gives it up below 7mph.

 

[gaijin]

For the 2018 Land Cruiser:

Dynamic Radar Cruise Control (TSS-P 25 only)
Intended for highways and similar to “constant speed” cruise control, Dynamic Radar Cruise Control (DRCC) 21 lets you drive at a preset speed. DRCC uses vehicle-to-vehicle distance control, which adjusts your speed, to help you maintain a preset distance from vehicles ahead of you that are driving at a slower speed. DRCC uses a front-grille-mounted radar and an in-vehicle camera to detect vehicles and their distance. If a driver is traveling slower than you, or within your preset range, DRCC will automatically slow your vehicle down without deactivating cruise control. If DRCC determines you need to slow down more, an audio and visual alert notifies you and brakes are applied. When there’s no longer a vehicle driving slower than your set speed in front of you, DRCC will then accelerate and regular cruise control will resume.

And:

Pre-Collision System with Pedestrian Detection (TSS-P 25 only)
Using an in-vehicle camera and radar to help detect a vehicle or a pedestrian in front of you, the Pre-Collision System 24 with Pedestrian Detection 26 (PCS w/PD) can help you mitigate or avoid a potential collision. If the system determines that a frontal collision is likely, it prompts you to take action using audio and visual alerts. If you notice the potential collision and apply the brakes, PCS w/PD may apply additional force using Brake Assist (BA). 23 If you don’t brake in time, it may automatically apply the brakes to reduce your speed, helping to minimize the likelihood of a frontal collision or reduce its severity.

HTH

 

[GoISU]

It sounds like PreCollision won’t bring your truck to a screeching halt if a hazard enters your path or you disregard a potentionlly dangerous condition. It only slows the vehicle to reduce impacts. That makes sense since I’ve never felt preCol intervene but I have had the brake assist kick on and pretension the belts etc.

I also agree that the radar cruise would never apply the brakes without illuminating the tail lamps, I still think it uses engine braking to add a smoother slow down when required. I find this feature amazing when there’s a lane reduction and construction speed zone. I had it slow me from 80mph to 45mph and then take me back to 80mph in a pretty nice fashion depending how the car in front of me slows.

 

[OregonLC]

I’d like a Pre-Ticket Defense System (PTDS)! It would automatically brake to posted speed when it detected that a traffic citation was imminent.

 

[KLF]

I’d like a Pre-Ticket Defense System (PTDS)! It would automatically brake to posted speed when it detected that a traffic citation was imminent.

I'm sure Musk is working on that!

 

[Dan Higgins]

So on a drive today I tried out DRCC while descending a 6% grade. I brought the LC to 60mph as we started heading down the grade then quickly changed the DRCC speed setting to 50. Then I watched as it stepped through 3 gear changes to create enough engine braking to bring the speed down to 50. Shifts were about 5 secs apart. Clearly doing downshifts to control the speed. Now I don't know if it would do that when slowing down due to encountering a slightly slower vehicle in front. But it suggests that using engine braking and even downshifting to create it is something that it can do to control speed.