Safe Speed Forums

I don't think that's necessarily true. We could possibly move towards "learning systems" where the system could learn from experience. We could potentially gather and integrate the experiences of thousands of vehicles and clone the experience into every system.

I still don't believe it'll ever happen.

_________________
Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety

I think there is possibly one scenario where this will help. It is... where the driver is speedo-gazing, thanks to scameras .

In fact, provided there are three independent sensor systems (to avoid false alarms from birds etc), and provided the brakes are applied when a collision is otherwise unavoidable (ie, the steering if placed on lock could not miss the obstacle, and the vehicle steering is already within a tad of centre (ie driver not trying to steer round the obstacle), and rate of closure is such that thingy in front WILL be hit, I could tolerate a damage-limitation emergency braking system then - much like the airbag - to mitigate the inevitable. That would leave the driver in full control until he'd lost it.

I'll stay indoors during the learning period if you don't mind. In fact, depending on where you live, that might not be safe enough.

I very much like the idea of using the electronics in a last ditch attempt to mimimise damage, but...

I think there are too many variables affectig braking distance for this to work. Wet/dry road and uphill/downhill are pretty big effects. Then there's tyre condition and half a dozen other smaller effects.

Then there's movement of the collision object vehicle. Our driver may know that the collision object will have moved before we arrive - I don't see how the electronics can know this.

On occasion we might plan to drive into parked cars to avoid a pedestrian or even accept a collision ahead to avoid one from the side. I agree that such situations are rare indeed, but they do exist.

And how is the damn system going to behave if I have the temerity to try to drive in snowy conditions?

_________________
Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety

It's quite possible that such a system could be learning while there was a driver in control.

_________________
Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety

Yes - so the last ditch system will ONLY bang on the brakes when approx 1g is insufficient to stop before the gap closes and it will release the pedal in the unlikely event of the obstacle taking off.

No it can't, hence the need to not apply the brakes until all other driver-induced options have been given every chance.

Agreed also - so the system should only cut in when the steering is near straight ahead and the inevitable obstacle....

Unless we also have the temerity to do "dry road" speeds on the snow, the system will never cut in.

Yep. Good answers. Thanks. I still don't want one.

_________________
Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety

Most secondary/last ditch safety features of today are not noticeible except when an accident occurs. Exceptions are the increased safety structure (thick pillars), the passenger side airbag (no flat dash and a small glovebox), some ALB systems (a dashpot effect on the pedal making it impossible to stamp exceptionally fast on the pedal with immediate effect - plus all the other effects that can occur as discussed elsewhere)

I think this would truly be one that would never cut in except in the .3 of a second leading up to an accident - and whilst I wouldn't refuse one, I wouldn't want to pay extra for it.

I.E about 3 mph slower... seems a little bit pointless

Not so. In 0.3 sec at 1g deceleration, one can scrub off ~ 10 ft/sec - 600 ft/min - 36000 ft/hr - approx 20 mph. Remember, there is no thinking time - this system is continually thinking and this is its sole job.

If the driver is speedo gazing at 40, this will make impact effects of a collision a quarter as bad for both parties.

We already have both technologies - the "power assisit" breaks used in Mercs has a trigger of driver hittingh pedal above a certain pressure, and sensors to determine by successive measurements only miliseconds apart when collision is 0.3 sec away. This is growing on me, provided it remainsa as a last ditch arrangement and only cuts in when the inewvitable is on the cards as damage limitation.

A bit off the wall, but I guess, in the event of a really high closing speed collision in the offing, the system could fire a bolt into the road and have a hauser giving further controlled deceleration. Too far fetched? Too risky? Probably, but what fun

This isn't right although the logic looks good. 1g decceleration is about 20mph per second. 32ft/sec/sec / 1.46667 = 21.8mph/sec/sec

0.9g is probably more realistic at 20mph per second.

Ahh, I found the error. 36,000 feet is 6.81 miles.

_________________
Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety

Ok - I can't add up then - but it's still worth it.

For the record, I forgot the feet-to-yards part.

All very well, but what's been proposed is collision avodance radar. I'm pretty sceptical for 3 reasons. I don't think it'll be as effective as a human driver at making those subtle judgements of when a crash is going to happen. I think it may be fooled into thinking a crash is about to happen when it isn't. And I don't like the idea of the lazier droivers trusting to the electronics to get 'em out of trouble after they screw up. AFAICT the only advantage such a system could have is that it would have a better reaction time than a human being. Big deal. Doesn't beat thinking ahead if you ask me.

_________________
Make everything as simple as possible, but not simpler - Einstein