DRCC operation

I think it's at it's best in highway speeds, fits in with other traffic superbly. I drove for 2 hrs on 2nd grade highways the other day and only used the brake/accelerator once - when I stopped for a snack.

I haven't found it to leave 3 car lengths while driving, though if it comes to a complete stop, it's not as close as I would be - leaving 10' instead of 3' or 4' I'd do myself. If it's tight traffic and looks like it'll be stopped more than a second or 2, I'll nudge it forward to close that gap a bit.

Yes, seems better in PWR. Also, if it's come completely to a stop, I use accelerator for a second or 2 to get it started quicker, then leave it to itself.

 

Feel the PWR.

 

Yes, there is a noticeable difference between ECO (my preferred setting) and normal and power when using DRCC. Even though DRCC doesn't keep up with the car in front of you, it hits the accelerator harder than ECO, lessening the difference between you and the car in front, keeping of course the set distance DRCC is controlling.

 

In ECO - there is a dip on the motorway I drive most days - about 1 km downhill run, she keeps spot on 102km/hr till she hits the bottom, then loses the plot and doesn't accelerate enough to keep up and drops to 97ish after the dip, gradually getting back up to the crest, then overshoots the speed as it levels off, getting up to 105/106.

BUT - in PWR, she reacts quicker, only slowing to 99 after the dip and overshooting less, maybe 104 at the top. Other areas I've found she's much more obedient in PWR.

 

Re: 3 car lengths in the o.p. and the "set distance" in the above, of course the DRCC setting is not strictly one of distance, it's stopping time, which varies the distance according to the vehicle's speed.

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I personally don't like DRCC much - because it's driving style is mimicking that of other drivers, which in Germany is quite "jumpy" - braking hard last minute and accelerating hard to go as fast as possible in the least amount of time, instead of trying to keep a smooth reasonable ride.

Moreover I have noticed that in the summer and some other "corner cases" it brakes "out of the blue" I think as a result of the difference of air density and temperature in front of the car moved by e.g. the truck's size. And it also does not work well when the highway bends a lot. It would accelerate all of a sudden because the car in front "disappears" from the radar's view when it is most dangerous (approaching a bend).

I prefer DRCC in slower bumper to bumper traffic. I usually set it with the lowest of the 3 distance settings always, because by default it leaves so much space that a lot of stupid drivers, thinking you are not going fast enough (while in fact you are leaving necessary braking space), cut in, and the DRCC then ends up braking again. Overall the ride then results as jumpy and the fuel consumption is higher, because in ECO it accelerates so slowly that the person behind you gets annoyed (and myself too), so you need to set it to Normal or PWR mode, where it accelerates too hard, often when not necessary (no car behind), to reach the set speed, ending in the PWR area of the HSI bar.

Yes, the modes do affect the way the car will accelerate in DRCC mode.

I prefer more the speed limiter and the normal CC, as I can better modulate the speed and achieve a more constant speed (and thus better fuel economy). Often cars in front brake hard and accelerate hard within the time I simply let the car roll, getting the car getting closer in a controlled fashion (my foot is ready on the brake). The DRCC would simply just brake hard when I already see beyond the car in front of me that there is no need to brake anymore and simply releasing the gas pedal would do the trick. The DRCC doesn't see beyond the car in front of you and doesn't know what the road ahead looks like (bends).

A good benefit of the DRCC though is that it recognizes at a distance if a car is slowing down hard, before you realize it yourself because distracted for some reason or it is too far away. Sometimes though it starts braking a long time before it is necessary. If for example I drive 140km/h and well far away some guy drives at 80km/h (because the highways are the best places to save fuel, aren't they? - in face of security and hindering traffic flow), it starts slowing down too much in advance, so to keep the speed constant you have to change lanes so early it seems you are in the left lane for no reason... (annoying possible other drivers behind you).

What I like a lot instead is the LKA (lane keep assist) and LDW (lane departure warning). The first actively keeps the car in the lane, by making the steering just a tad harder when you sway. And it beeps complaining you are not setting the blinker when changing lanes. I sometimes forget about it...

One thing I am not using at all, is the traffic sign recognition - in EU trucks have small badges showing which is the max speed they can drive on highways and regional roads. The software does not understand that they are not regular signs (if I am driving at 130km/h, how fast should a sign get bigger and bigger approaching it? surely not at 50km/h if approaching a truck driving 80km/h, shouldn't it? the Prius RSA does not understand this it seems), so you might be in a 130km/h zone, and all of a sudden, it reads the badge on a truck and the Prius shows 80km/h as a limit. If you didn't pay attention, you think you are speeding badly and end up braking for no reason. Confusing. I hope they have a software update for this. Otherwise it will stay off.

I am really wondering if we will ever get any software updates for all the ADAS (Advanced Driver Assistance Systems) systems in the car, when we get it serviced, and if yes, if they will let us know.

 

Similarly to your trucks, but probably worse, we have "40"km/hr signs on the back of school buses. (The "40" speed imposition is only when a school bus is stopped at a bus stop.) And, that is the reason, I believe, that the traffic sign recognition software isn't offered here - sudden braking to 40 wouldn't be pleasant or safe.

 

I actually wish the speed limiter functionality were available in the US market, it'd be an interesting way to keep the vehicle within a range of speeds without needing error-prone DRCC.

And school buses in Australia actually can be passed when they're stopped? In the US, all traffic (in many cases, going both directions) must stop for a school bus.

 

A couple of these posts seem to suggest that you can select between DRCC and CC in cars with DRCC, or am I just not interpreting the comment correctly.

Personally, I like DRCC and it is the primary reason I traded my Gen 3 for the Gen 4.

 

Yes, you can set constant speed cruise control by holding down the on button for 3 seconds. I have only used it once just to see how it worked, but always use DRCC.

 

And, according to the manual (didn't try myself), when you start the car, it is always starts with DRCC.

 

Just read that whereas in non dynamic, constant speed mode the Cruise Control lever changes the speed in 1mph units, in DRCC mode, it uses 5kph, 3.1mph units.

Seems like this will make it harder to set an exact cruise speed, only way being to get the car to that exact speed before locking on to it.

With the old system you could get near to the required speed and then add 1 or 2 mph easily.

How do folk find this in practice?

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Try holding for a couple of secs for the 5 or 10mph increments and just a quick tap for the single step.

 

I don't have Drcc yet just standard CC on my gen2, but my point is that the manual says that the single step has increased from 1 mph to 3.1. So I guess that must make it more difficult to get fine control of speed when needed?

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OK, in that case your best bet would be to set your ideal speed using pedals then set cruise control at that speed. It may take a short time to get used to, but just as accurate.

 

I guess that is the only option now with DRCC.

Not sure what the benefit is of the change, seems like a backward step to make the fine control more coarse. I find it much easier to use the fine adjustment than get the speed just right with the pedal.

Does the DRCC adjust to keep within speed limits detected by the speed sign camera?

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Not from my experience. Two completely independent features I believe.