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Auto speed limiter for cars

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Auto speed limiter for cars

Old 12th Oct 2017, 08:33
  #21 (permalink)  
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If you need to bust the limit for some reason, for example to accelerate away from a dangerous situation you just switch the system off and put your foot down. Many cars already feature a spring detent incorporated into the pedal movement to limit power when it's not needed. It would just need a minor tweak to link this to the GPS control input - foot through the detent would also deactivate the auto speed control system.
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Old 12th Oct 2017, 09:05
  #22 (permalink)  
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Tsk, tsk, tsk - is everyone forgetting that GPS only gives you your ground speed, not your airspeed?
Does it know you are on a hill - ground speed calculated as if ground is flat, 70, ground speed down the slope of a hill, 71, result endorsement.
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Old 12th Oct 2017, 11:10
  #23 (permalink)  
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Our council, and I am sure others, are quite active in changing the limits. Whole stretches of 60 now 50. Or my GPS occasionally has a false segment with an erroneous drop to 30 in a 50 zone.

Then my car Satnav has a DVD update, and no speed info, at more than 12 month intervals.
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Old 12th Oct 2017, 11:18
  #24 (permalink)  
 
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Our new Skoda Superb has VW Groups Active Cruise Control which when engaged slows down and speeds up according to the proximity of the vehicle in front, and frankly I found very unnerving to start with as i felt thoroughly out of control of the vehicle, however now I'm used to it, and how it's brain works I've realised one of the benefits is that it drives leaving much more space between me and the vehicle in front than normally would, which is obviously safer, though infuriating when some idiot decides to move across my lane to exit at a slip road, as the car first brakes, then warms to brake manually to avoid an incident, and in the process disengages the ACC, even though I am fully aware of what is happening myself.
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Old 12th Oct 2017, 11:37
  #25 (permalink)  
 
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ATNotts

The problem with such driver assists is that the driver no longer concentrates

On the motorway you give too much gap and you are guaranteed that someone will zip up the inner lane and take that space by chopping in front
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Old 12th Oct 2017, 11:43
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Originally Posted by Pace View Post
ATNotts

The problem with such driver assists is that the driver no longer concentrates

On the motorway you give too much gap and you are guaranteed that someone will zip up the inner lane and take that space by chopping in front
Exactly that, and so far I have forced myself into not relaxing too much, this development is another step on the route towards fully self driving cars, and I don't know whether it's just an age thing, but i dread that day arriving, and fear it will arrive before it's time for me to hand back my licence.

As for zipping across, it happens every day to me on the motorway, far too frequently the culprits are white vans and Merc / BMW drivers, along with boy-racers in Subaru and Mitsubishi high performance cars, and the self-driving technology is going to have to be pretty smart to avoid colliding with those mindless idiots.
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Old 12th Oct 2017, 12:24
  #27 (permalink)  
 
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My car (Jag F-Pace) has the following:

1. Normal Cruise Control - fixed speed as normal
2. Speed Limiter - set max speed, and whatever you do it won't exceed that speed
...
Are you sure? My car (a 13 year old Merc) has a speed limiter - which stays in place until you disengage it by either:
1. Flicking the lever, or
2. Applying full throttle (accelerator touches the floor).

I assumed that was a standard safety feature for these systems - is it just that you haven't read the manual/attempted full throttle?
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Old 12th Oct 2017, 12:43
  #28 (permalink)  
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Originally Posted by UniFoxOs View Post
Does it know you are on a hill - ground speed calculated as if ground is flat, 70, ground speed down the slope of a hill, 71, result endorsement.
Perhaps not a huge problem.

1 mph difference on a 10 degree slope, mph on 5 degree slope
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Old 12th Oct 2017, 13:13
  #29 (permalink)  
 
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With modern engines and suspension systems, todays hot hatch has the performance of an exotic supercar from the 1970s. Instead of tuning up a Ford Escort, a modern tear away can simply purchase performance that would previously have required extensive and expensive engine modifications, from a used car lot.

Unfortunately skill and judgement amongst young drivers hasn’t increased in-line with advances in vehicle technology. Insurers have played a part in restricting access to high performance cars by the under 25s with eye watering premiums.

Can anyone remember the Sierra Cosworth ? The most stolen car in Britain and almost impossible to insure at any price.
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Old 12th Oct 2017, 13:45
  #30 (permalink)  
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The other automatic device which will lead to skill fade is parking assist and automatic parking. I know two or three people with automatic parking who are scared to use it. I read though that a line of cars, all parked automatically, would use 20% less road space.

That obviously doesn't apply in Paris.
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Old 12th Oct 2017, 15:09
  #31 (permalink)  
 
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[QUOTE=Pontius Navigator;9922640]The other automatic device which will lead to skill fade is parking assist and automatic parking. I know two or three people with automatic parking who are scared to use it. I read though that a line of cars, all parked automatically, would use 20% less road space.QUOTE]

Not sure how that works. The brochure for a possible replacement for our current car talks about automatic parking getting the car into a space 120% of the car's length. Chez Luggage we can (and have to) get into spaces 107% of the car's length, without Parisien techniques.
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Old 12th Oct 2017, 15:13
  #32 (permalink)  
 
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Some diesels, mostly non-turbo, already have an rpm limiter. Bloody annoying/embarassing/dangerous when you're trying to overtake someone!
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Old 12th Oct 2017, 15:31
  #33 (permalink)  
 
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Originally Posted by aox View Post
Perhaps not a huge problem.

1 mph difference on a 10 degree slope, mph on 5 degree slope
And most car speedos exaggerate by 10% anyway.
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Old 12th Oct 2017, 15:37
  #34 (permalink)  
 
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Hmmmmm..... I'm just imagining an overturned and leaking fuel tanker, next to which some clot is smoking... and my car refusing to leave the scene at more than 30 mph. The stuff nightmares are made of.

That said, Psychologists have confirmed that most murders are done in the heat of the moment and that prior knowledge of eg the Death Penalty would not much reduce the number of murders. They also state that knowledge of the Death Penalty for eg minor crimes where no heat of the moment is involved, definitely would reduce their incidence. The answer is therefore simple:

SPEEDING = DEATH PENALTY.
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Old 12th Oct 2017, 15:47
  #35 (permalink)  
 
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I've experinced mulitple occasions when overtaking someone who's driving below the speed limit under conditions that easily allow for faster driving. They suddenly wake up as I'm passing and treat it as a personal affront to their masculinity and begin to accelerate causing a dangerous situation to oncoming traffic.. a speed limiter would prevent me from getting out of a nasty fix.
Incidentally, if there's anyone here guilty of that sort of stupidity what do you think I would do if the alternatives are colliding head on with an innocent motorist coming in the other direction or running this idiot who's alongside off into the agriculture,, you needn't think for too long.
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Old 12th Oct 2017, 15:57
  #36 (permalink)  
 
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Originally Posted by andytug View Post
And most car speedos exaggerate by 10% anyway.
Most? Hardly. To account for tolerances the requirement is speedos may over read by up to 10% but not under read (i.e. true speed +10%/-0%). There is also reading error to take into account as well which adds another 2.5 mph to allow for a fat needle, fat dial markings and viewing angle.

The result? That slow lane hog in front of you is probably doing the same indicated speed as you but you're gaining on him at 8mph.

Last edited by Carry0nLuggage; 13th Oct 2017 at 08:36. Reason: over/under Doh!- Thanks to 747 jock for spotting that
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Old 12th Oct 2017, 17:23
  #37 (permalink)  
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And most car speedos exaggerate by 10% anyway.
Yes, but I assumed that for accuracy the GPS would control the speed, therefore you could be driving at an accurate 70, by the GPS, and be booked for 71 by plod's radar. Some forces do not allow any tolerance nowadays.
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Old 12th Oct 2017, 17:38
  #38 (permalink)  
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Why, if your 70 is accurate would a plod book you at 71?
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Old 12th Oct 2017, 18:28
  #39 (permalink)  
 
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Originally Posted by WingNut60 View Post

One thing to remember is that the vast majority of speeding convictions are against people who are knowingly and willfully driving in excess of the speed limit.

That certainly wasn't the case when I did my Speed Awareness Course. They did a quick survey at the beginning to ascertain who was caught doing what in what limit so that they could tailor the course accordingly. Of the 19 people on the course the breakdown was as follows;

1 person (me) caught on a motorway, 83mph and I knew I was speeding.
2 people caught in 50 limits, 1 knew they were speeding, 1 didn't.
2 people caught in 40 limits, both had no idea they were speeding.
14 people caught in a 30, most had either no idea they were speeding or no idea of the limit at that time.

If that course was typical it indicates that the problem is lack of awareness in general, not habitual and wilful speeders.
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Old 12th Oct 2017, 19:22
  #40 (permalink)  
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Originally Posted by UniFoxOs View Post
Yes, but I assumed that for accuracy the GPS would control the speed, therefore you could be driving at an accurate 70, by the GPS, and be booked for 71 by plod's radar. Some forces do not allow any tolerance nowadays.
I neglected to point out in my previous post that the two examples I gave there are much steeper than the typical slope on a motorway.

Maximum motorway gradients are of the order of 3, exceptionally 4, so you're pretty unlikely to have more than 0.1 mph error.

Yes, you might have steeper slopes on non-motorway roads, but then you'd be dealing with a slightly larger percentage of a lower speed limit.

On top of that, it's possible that the GPS calculates and displays the real speed while climbing and descending. Expert comment needed, in case anyone is still worried about such small corrections, as I don't actually know. But I'll assume so, as after all the system is three dimensional, and being on the earth's surface is a set of cases, not the whole lot.

Last edited by aox; 12th Oct 2017 at 20:08.
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