Post by
POBINVA »
https://forums.nicoclub.com/pobinva-u240752.html
Tue Aug 04, 2015 2:08 pm
Clearly this is a problem for a lot of us. The few times ours has gone off (we've now owned the car for 1 year this month, and have about 11K on it) I would say that our experience is similar to the input noted above - my best guess is that you'd have about a second to react. In my mind, that's not adequate to consider this a functional warning system, at least the way it's working in my car. At 60 mph, in 1 second your vehicle has gone 88 feet. Just for perspective, a 2014/15 Rogue is 182.3" long - that's about 15 feet. So at 60mph, with one second's warning, you would DRIVE THROUGH almost 6 Rogues parked end-to-end. Perhaps more important are the measured braking distances - Car & Driver tested 70 to 0 in 170 ft, but to keep the 60 mph concept - Edmunds tested 60 to 0 at 124 feet, Consumer Reports 60 to 0 in 134 feet (those are published figures). So with that ONE SECOND's warning, if you SLAMMED ON THE ANTILOCK brakes, you're still going to travel through (using the 60mph braking figures, averaged) about 9 Rogues on your way to a dead stop. Now maybe you don't need to come to a complete stop, but to me, those numbers are not very reassuring! And that assumes you have the reflexes of superman to be able to recognize that you do need to stop, to raise your foot to the brake and apply it. If you give a full second for all of that to happen - visual/auditory signal to hit the brain, recognize it, brain to leg signal, etc., you've already hit the car in front of you. Before you even apply the brakes to travel 124-134 feet in the next second, 60 to 0.
I've thought a lot about this issue - designing a FCW system, from an engineering perspective, certainly must be a challenge. And any design, of any system, is a series of compromises. In this case, one has to be concerned about false positive warnings (which will lead the driver to ignore them) - the system alerting when nothing's imminently dangerous, and false negative ("silence from the system") risks. I personally think that the system on the Rogue has too many "false negatives," that it's TOO quiet. BUT, the "positive predictive value" is very high - IF the system goes off, you are indeed about to crash! The question is - can you do anything about it? That's what's the problem - I don't think so (see the thought process above - maybe I'm right, maybe I'm wrong, but the margins look pretty slim, to me).
We've only had about 4 alarms in a YEAR (as noted, for us ~ 11,000 miles). Now hopefully that's because my wife and I drive safely and isolate ourselves on the road. I'm personally not driving around looking to set the system off and no, I've personally not tried driving at cardboard boxes. One of my alerts was when someone cut in front of me way too close. I honestly can't say if I'd put the brakes on first or if the system alarmed and I was putting the brakes on at the same time - it was all too fast. The other one I remember was when someone pulled out of a side street (incidentally on the passenger side) and cut me off. But I'll say for sure on that one if I hadn't already been looking and swerved/braked (let's say if I'd been distracted/looking the other way) I very likely would have hit the car, because the warning from FCW was so negligible. But what's obviously got my attention, and that of everyone else commenting, is that there have been quite a few situations under which I would have LIKED, or EXPECTED the system to alarm, and it's NOT.
roguegnagle - if you learn anything from YOUR dealer (mine was clueless, as was the regional Nissan service rep, and Nissan USA never replied to several communications that I sent them), PLEASE share with us!
? I'm really concerned at this point that it's working. It's a brand new system from what I can tell, likely heavily dependent upon software, so glitches may be present.
