speed time calculation and NIp
Discussion
I have posted a topic in the general gassing section which I think should have been here.
Basically, I have got the photos after beeing lasered at 41mph. I am adamant that I wasn't speeding.
The time between the 2 pix show a time interval of 6 seconds. The distance I travelled was 63 yards, measured by me using clearly identifiable markings on the road. That equates to an average speed of 21 mph, which is more likely as I was looking for a side road, some 40 yards up from the second photo.
Please have a look and see what you think...
http://www.petrolheads.co.uk/gassing/topic.asp?t=185622&f=23&h=0
Basically, I have got the photos after beeing lasered at 41mph. I am adamant that I wasn't speeding.
The time between the 2 pix show a time interval of 6 seconds. The distance I travelled was 63 yards, measured by me using clearly identifiable markings on the road. That equates to an average speed of 21 mph, which is more likely as I was looking for a side road, some 40 yards up from the second photo.
Please have a look and see what you think...
http://www.petrolheads.co.uk/gassing/topic.asp?t=185622&f=23&h=0
Sorry to be the bearer of bad tidings, but you (and everyone else) have got this wrong.
The device that nabbed you was the LTi20/20. It doesn't work like a GATSO or SPECS (which measures you over two points). It's a laser gun which is linked to a video recorder. The only frame that matters is LOG 002 which shows the 041mph reading. The second photo (LOG 003) is merely a close up picture to show who was behind the wheel: it doesn't have any bearing on the speed measurement.
If you wish to dispute the charge then you will first have to plead not guilty and seek the evidence against you.
Get over www.pepipoo.com for some considered advice.
The device that nabbed you was the LTi20/20. It doesn't work like a GATSO or SPECS (which measures you over two points). It's a laser gun which is linked to a video recorder. The only frame that matters is LOG 002 which shows the 041mph reading. The second photo (LOG 003) is merely a close up picture to show who was behind the wheel: it doesn't have any bearing on the speed measurement.
If you wish to dispute the charge then you will first have to plead not guilty and seek the evidence against you.
Get over www.pepipoo.com for some considered advice.
I seem to remember reading somewhere that there are 4 frames of the video between being pinged and the machine timing out and deciding your worthy of making a contribution to the christmas party fund.
So I think your looking at about 1/16th of a second for it to nab you, after the officer has decided he thinks your above te limit that is.
So I think your looking at about 1/16th of a second for it to nab you, after the officer has decided he thinks your above te limit that is.
The machine takes 43 distance measurements over a 0.3 second period, not only that but after the first 5 readings it predicts from the average speed over these 5 readings where your vehicle will be, within a few 10's of mm, for the remainder of the readings.
You can do a time distance calculation where the frame count N/R on the shots indicate the fractions of a second on the times of the frame.
When you have an accurate distance and the very accurate time, the frame counter must be stable to within a few 10's of microseconds to meet approval, you can compute the AVERAGE SPEED after your speed was measured.
To be valid as a defence to an inaccurate reading and to be relevant, you must compute your speed in this manner in the time BEFORE you were measured, not after, as drivers always slow down as a camera vehicle becomes visible. I would suggest that if your average speed was indeed 21 mph you would be typical of the type of driver who drives in ignorance of the speed limit, often above it, then overcompensates the reduction in speed after detecting the measurement device.
The calculation of average speed after you have been measured shown in this thread and the other one containing this has not shown anyone who has explained how to work out the fractions of a second from the frame counter so you have not calculated the time/distance correctly anyway.
To calculate the fractions of a second from the frame counter Take the N/R number, say 25, then divide by 50. i.e. 25/50 = 0.5, so frame 25 is about half a second.
I have caried out many of these calculations and have yet to find one that does not corroborate the speed reading at the point the offence was gathered. I have found loads that indicate an average speed that is lower than that measured just after the offence. These always feature a driver looking directly at the camera usually with the mouth either wide open or, using my elementary lip reading skills, mouthing the letter 'F'.
Cheers all!
You can do a time distance calculation where the frame count N/R on the shots indicate the fractions of a second on the times of the frame.
When you have an accurate distance and the very accurate time, the frame counter must be stable to within a few 10's of microseconds to meet approval, you can compute the AVERAGE SPEED after your speed was measured.
To be valid as a defence to an inaccurate reading and to be relevant, you must compute your speed in this manner in the time BEFORE you were measured, not after, as drivers always slow down as a camera vehicle becomes visible. I would suggest that if your average speed was indeed 21 mph you would be typical of the type of driver who drives in ignorance of the speed limit, often above it, then overcompensates the reduction in speed after detecting the measurement device.
The calculation of average speed after you have been measured shown in this thread and the other one containing this has not shown anyone who has explained how to work out the fractions of a second from the frame counter so you have not calculated the time/distance correctly anyway.
To calculate the fractions of a second from the frame counter Take the N/R number, say 25, then divide by 50. i.e. 25/50 = 0.5, so frame 25 is about half a second.
I have caried out many of these calculations and have yet to find one that does not corroborate the speed reading at the point the offence was gathered. I have found loads that indicate an average speed that is lower than that measured just after the offence. These always feature a driver looking directly at the camera usually with the mouth either wide open or, using my elementary lip reading skills, mouthing the letter 'F'.
Cheers all!
Drive around with a balaclava on... also a very dirty car with obscured plates.
Honestly though, 41mph there, oh my god, looks really dangerous too
NOT
Just unlucky mate, feel sorry for ya. I'd be likley to just stop in the road near the scamera and put my hazards on just where cars come into view of it for an hour or so just to loose them some revenue
Dumb ass scamera operators, probably let the bank robbers with guns in their hands in a stolen transit van go past as they were going under 30mph.
Let me guess, do scamera operators have "targets" for amount caught these days?
Because it's all about safety and reducing accidents...
Dave
Honestly though, 41mph there, oh my god, looks really dangerous too
NOT Just unlucky mate, feel sorry for ya. I'd be likley to just stop in the road near the scamera and put my hazards on just where cars come into view of it for an hour or so just to loose them some revenue
Dumb ass scamera operators, probably let the bank robbers with guns in their hands in a stolen transit van go past as they were going under 30mph.
Let me guess, do scamera operators have "targets" for amount caught these days?
Because it's all about safety and reducing accidents...
Dave
destructive Steviebabes said:
To be valid as a defence to an inaccurate reading and to be relevant, you must compute your speed in this manner in the time BEFORE you were measured, not after, as drivers always slow down as a camera vehicle becomes visible.
Ist why you hide them in the foliage - nicht?
He will claim they do not do this - but Mad Doc, und Ernest have the similar photos
destructive Steviebabes said:
I would suggest that if your average speed was indeed 21 mph you would be typical of the type of driver who drives in ignorance of the speed limit, often above it, then overcompensates the reduction in speed after detecting the measurement device.
The calculation of average speed after you have been measured shown in this thread and the other one containing this has not shown anyone who has explained how to work out the fractions of a second from the frame counter so you have not calculated the time/distance correctly anyway.
If I recall from andy's past posts - he ist involved in track und timing speed very accurately - und I would think from this und his son's web site (if have recalled correctly) that his calculations would be more accurate than you give credit for. But then Liebchen - you keep trying to tell me you are doing good job und keeping me safe from the idiots - und yet I see know real improvement anyway - und this ist from your own figures too.
destructive Steviebabes said:
These always feature a driver looking directly at the camera usually with the mouth either wide open or, using my elementary lip reading skills, mouthing the letter 'F'.
Cheers all!
You are trying to lipread the kittens - who usually mouth something rude each time we pass
But - you have never managed to cop either of us yet....as we know your little tricks! But I detect smug gloating here ...ist not a joke Steviebabes und you should not hide those vans if you intend to get a slow down in area. It proves you are only intersted on making loot really
>> Edited by WildCat on Monday 13th June 13:08
The video from before the first pic would be interesting - if as you state you were doing ~22mph, then the most logical way the laser could have read 41mph is if the operator lased through your air-dam to the radiator, then lifted the point of aim while "pulling the trigger", ending on your VRM. Gap on a Civic from radiator to VRM will be at least 30cm. At a 0.3s gap between lases, 30cm = 1m/s which implies that to get a 20mph increase, an interval between lases of roughly 0.05s would be required.
Destroyer's comments about the LTI's operation are worrying though, as if that is true it should refute this.
Tricky one - if you are genuinely innocent, may be worth pursuing, but no guarantees, not with the current regime.
Destroyer's comments about the LTI's operation are worrying though, as if that is true it should refute this.
Tricky one - if you are genuinely innocent, may be worth pursuing, but no guarantees, not with the current regime.
destroyer said:
To be valid as a defence to an inaccurate reading and to be relevant, you must compute your speed in this manner in the time BEFORE you were measured, not after, as drivers always slow down as a camera vehicle becomes visible. I would suggest that if your average speed was indeed 21 mph you would be typical of the type of driver who drives in ignorance of the speed limit, often above it, then overcompensates the reduction in speed after detecting the measurement device.
I don’t disagree. This is why you must demand a copy of the video, including the position calibration procedure at the beginning of the tape.
destroyer said:
To calculate the fractions of a second from the frame counter Take the N/R number, say 25, then divide by 50. i.e. 25/50 = 0.5, so frame 25 is about half a second.
I have 1 quick question if I may: Does the frame counter increment by 1 for every interlaced frame, or by 2 for every full frame?
destroyer said:Have you also seen drivers slam on the anchors, giving great demonstrations of uncontrolled and dangerous slides?
I have caried out many of these calculations and have yet to find one that does not corroborate the speed reading at the point the offence was gathered. I have found loads that indicate an average speed that is lower than that measured just after the offence. These always feature a driver looking directly at the camera usually with the mouth either wide open or, using my elementary lip reading skills, mouthing the letter 'F'.
destroyer said:
I would suggest if your average speed was indeed 21 mph you would be typical of the type of driver who drives in ignorance of the speed limit, often above it, then overcompensates the reduction in speed after detecting the measurement device.
Er - I knew what the speed limit is, I was definately doing a lot less than 41 mph as I was coasting, off the gas looking for a side road which in fact was 30m further on than the last photo. I didn't see the motorcycle plod and slam the brakes on. In fact I saw the plod, looked at my speedo and thought, Thats ok then, I wasn't speeding!
So don't make assumptions about me you patronising muppet.
destroyer said:
I have caried out many of these calculations and have yet to find one that does not corroborate the speed reading at the point the offence was gathered. I have found loads that indicate an average speed that is lower than that measured just after the offence. These always feature a driver looking directly at the camera usually with the mouth either wide open or, using my elementary lip reading skills, mouthing the letter 'F'.
Cheers all!
Funny that, my father was involved with a court case not so long ago where he'd calculated that a driver wasn't breaking the limit and the claimed speed was way above the actual speed, the defendant won the case!
andygo said:
I would suggest if your average speed was indeed 21 mph you would be typical of the type of driver who drives in ignorance of the speed limit, often above it, then overcompensates the reduction in speed after detecting the measurement device.
Er - I knew what the speed limit is, I was definately doing a lot less than 41 mph as I was coasting, off the gas looking for a side road which in fact was 30m further on than the last photo. I didn't see the motorcycle plod and slam the brakes on. In fact I saw the plod, looked at my speedo and thought, Thats ok then, I wasn't speeding!
So don't make assumptions about me you patronising muppet.
The only muppetry on display here is the rather poor attempt at claimimg the inaccuracy of the device. I suggest you get a copy of your section of the tape and get someone who knows what they are looking for examine it to confirm or deny the speed. The speed will be that either side of your offence data. Then we'll see who the muppet is.
Send it up to me and if the speed is less than the measured speed I'll gladly sing some muppet type song for you.
I fear your ears will not have to suffer my voice though!
I see the "destroyer" still claims that laser devices are infallable. Given that all INDEPENDANT evidence suggests that they are at best used incorrectly in the majority of cases, at worst they are vastly inaccurate. I have a new name for Wildy's "steveibabes" and that is "Ostrich". It has a small brain sings awfully and buries its head in the sand when something happens it doesn't like!
>> Edited by telecat on Monday 13th June 19:27
>> Edited by telecat on Monday 13th June 19:27
This is the same "device" that reads 58mph from the stationary walls!
www.bbc.co.uk/insideout/southwest/series7/speed-cameras.shtml
Its that good!
www.bbc.co.uk/insideout/southwest/series7/speed-cameras.shtml
Its that good!
destroyer said:
destroyer said:
I would suggest if your average speed was indeed 21 mph you would be typical of the type of driver who drives in ignorance of the speed limit, often above it, then overcompensates the reduction in speed after detecting the measurement device.
Er - I knew what the speed limit is, I was definately doing a lot less than 41 mph as I was coasting, off the gas looking for a side road which in fact was 30m further on than the last photo. I didn't see the motorcycle plod and slam the brakes on. In fact I saw the plod, looked at my speedo and thought, Thats ok then, I wasn't speeding!
So don't make assumptions about me you patronising muppet.
The only muppetry on display here is the rather poor attempt at claimimg the inaccuracy of the device. I suggest you get a copy of your section of the tape and get someone who knows what they are looking for examine it to confirm or deny the speed. The speed will be that either side of your offence data. Then we'll see who the muppet is.
Send it up to me and if the speed is less than the measured speed I'll gladly sing some muppet type song for you.
I fear your ears will not have to suffer my voice though!
Look sunshine, I really don't want to be rude or aggressive, but I KNOW I wasn't doing 41 mph.
I KNOW I didnt brake when I saw the plod. In fact it wasn't obvious that it was a plod at the time (funny that) so I felt no need to react to anything really.
I'm not saying the device was innaccurate, just that the device didn't give a true indication of my speed.
Lets face it, if I was sent out to catch a few speeders, I sure as hell would have learnt a few tricks to ensure I caught as many as possible in as short a timescale as possible so I could get back in the warm and scoff some pies and doughnuts.
If it had been a bit marginal, then fair (almost) cop, but 41mph is having a laugh.
And as far as some Plods integrity in Cumbria is concerned - well don't even go there1
A few years ago I was taking my lads up to Rowrah Kart track to race,veruy early on a sunday morning.
We overtook a white cavalier with 2 occupants. Clocked them, driver in a white shirt, female passenger in a white knitted top like my mum would wear.
Mile or so later overtook a damaged MKIII escort with a crew of young lads. Damaged insofar as the drivewrs door wouldn't shut properly and was flapping in th eslipstream.
Several miles later, I saw the flash of a hidden in the bumper blue plod light as it moved the sierra in front of it to one side. It was at leat 1/2 mile back.
I slowed down to 70mph from my cruising speed of 110.
The car caught me up and stopped me. It was the Vectra I had passed some 7 miles previously.
They told me that they had followed me and my speed was 94.5 mph and how lucky I was, as 95mph was an instant ban. I asked to see the video evidence from their onboard recorder. They looked at each other in a dodgy way and said it wasn't switched on.
When I said you have no proof and would contest it, they said, that in that case I would be reported for 96mph.
Kerching. £60 to Cumbrian Mafia.
So stop being so bloody niave and patronising you dipstick.
I know I was doing well over the ton for several miles on a deserted motorway, but they had to lie to nick me. It must go on all the time. They knew they had no real evidence and conveniently turned the video off.
And they wonder why they have little respect.
Sorry to the decent plod that post on here - at least you have ethics.
destroyer said:
The only muppetry on display here is the rather poor attempt at claimimg the inaccuracy of the device
www.pistonheads.com/gassing/topic.asp?t=174119&f
I have no wish to enter into any mud-slinging as it happens all the time on here, but in my experience the LTi20/20 is the most unreliable piece of kit available to the police. I'm astonished it actually got type approval.
andygo, if I were you I would plead not guilty and seek to obtain the video evidence against you. Go to www.pepipoo.com for some advice.
andygo, if I were you I would plead not guilty and seek to obtain the video evidence against you. Go to www.pepipoo.com for some advice.
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