2010 Volvo XC60 T6 AWD: Just Say "No" To Adaptive Cruise

This is a classic example of technology gone too far. Regular cruise control works perfectly fine - adaptive cruise control is a system for the truly lazy.

zoomzoom22:

I'd have to disagree....

It's nice to have on long distance trips, especially when you have semis in and out of the passing lane or the errant slow driver. Hitting cancel and resume can become rather annoying after a while.

If you don't take long road trips, then yes I'd have to agree it's annoying.

Jason:

I would thumb through the owner's manual. I know Infiniti has a way to revert to non-adaptive cruise control by holding the cruise button.

I hate other cars that have adaptive cruise control systems....it makes my radar detector go off and causes me to slow down! ;-)

I can see why Brent might like it. He lives in an area where the freeways aren't so tightly packed and filled with lane jumpers.

But I'm with Jay. The system is simply way too conservative. Even at the closest setting, the system maintains a generous and inviting gap for those who want to change lanes or merge in front from on-ramps. I find myself constantly pre-cancelling the system to prevent the inevitable (and dangerous) over-reaction that nearly led to the Volvo "front-ending" following cars a couple of times. If it's going to work properly, the system needs to look both forward and back to properly manage a gap that is closing on both ends.

The whole point of adaptive cruise is to provide a cruise control that can work with other cars around. But this very premise is flawed. The only cruise control for me is "dumb" cruise on open road. In traffic, I'll rely on my own powers of proximity awareness and my trusty right foot.

Dan Edmunds

Is it really the cruise control's fault that other drivers have no clue about proper spacing in traffic?

Dan is correct in noting that my use of the Volvo's ACC system was an early morning drive on roads less conjested that those in Los Angeles. In light traffic, the system's conservatism wasn't an issue, but I could see where LA's heavier traffic would make the ACC's operation annoying.

Brent

The Owner's Manual states that ACC "is primarily intended for use
on long straight roads in steady traffic, such as
on highways and other main roads." It also warns explicitly that ACC is not to be used in demanding traffic conditions such as city trafffic and on congested highways. Those are the typical limitations of regular cruise control. Use ACC as intended and it works fine.

Mercedes Benz's adaptive cruise control has additional functionality that allow its use in congested and stop-and-go situations. That functionality becomes available on the next generation of Volvo's ACC which debuts on the new S60; i.e., ACC with Queue Assist.

One other thing, Mercedes Benz's advanced ACC, Distronic Plus, is only available on expensive models such as the E-Class and S-Class. ACC isn't offered on less expensive models such as the GLK.

@calhon, exactly -- ACC can really only deal with desolate freeways. Conventional systems have much more latitude for use than ACC.

ACC would be fine if it could be switched to a conventional "dumb" system when needed. But it cannot be, and that's the problem.

@jkavanagh: "ACC can really only deal with desolate freeways" is clearly hyperbole. ACC cannot deal with demanding traffic situations where speeds are erratic and there are frequent lane changes or merges. Conventional cruise controls should not be used in those situations either.

@calhon: That's a cop-out. ACC cannot effectively manage mild traffic that conventional cruise can deal with smoothly and safely, and with fewer speed adjustments. Why would such situations be considered unsuitable for conventional cruise?

I say I'm not suprised, and I don't think anybody should be. If you're travelling at 70+ mph with a following distance close enough to prevent another car from getting between you and the car in front, there is absolutely no possible way that you will not rear-end the car in front if they have to brake suddenly. In fact, your foot probably won't even have enough time to leave the gas pedal before impact. Who actually thought that Volvo, the "safety" company, was going to allow you to set that short of a following distance? I can already hear the lawsuits. I am suprised other makes allow you to.

@jstandefer

From my experience the problem isn't so much the spacing between your car and the car in front, but how the system responds to that. Pretty much every system I've sampled has about the same minimum distance at highway speeds (around 100 ft), but it is how the system reacts when you approach slow-moving traffic that sets them apart.

For instance, in the Lexus system once the car senses a slower moving obstacle ahead (usually still 500ft away) it starts applying the brakes. Because of that, you have slowed to almost the speed of the person ahead when you still have hundreds of feet until you actually reach them. This makes it impossible to execute a lange change properly because the car starts slowing you down so early. (This is a problem if you know you are going to pass the person ahead, but you want to wait a few moments so the person coming up on you can pass your car without you pulling out and slowing them down)

The MB system, on the other hand, doesn't really start applying the brakes until you are almost right at your preset following distance, which means you have plenty of time to check you mirrors, etc. and calmly make your pass before the car starts cutting your speed.

It isn't that systems like Volvo's are more safety conscious, it is that they are less sophisticated and thus lack the capability of systems like Distronic Plus.