Vascar averages
Discussion
sotons2 said:
Unlucky mate... 
Try here www.ukspeedtraps.co.uk/speed03.htm
Cheers mate
Just noticed the distance it was measured over was recorded on the witness statement at .242 of a mile.
More than the minimum 1/8 mile then ?
You could do worse than visit www.pepipoo.co.uk if you haven't done so already - check out the Fightback Forums.
You could do worse than visit www.pepipoo.co.uk if you haven't done so already - check out the Fightback Forums.
sotons2 said:
More than the minimum 1/8 mile then ?
You could do worse than visit www.pepipoo.co.uk if you haven't done so already - check out the Fightback Forums.
Yep just under a quarter of a mile. The reading seems a bit high considering I started from traffic lights and the stretch of road can't be much more than 1/4 mile with a 40mph scam at the end of it which didn't trigger. The car was also being run in (< 3k rpm) that meant that I would have been no where near it's claimed 0-60 time(7 secs).
I'll check pepipoo but I'll prob just end up sending off the cheque
Something troubles me.
The following figures are rounded for ease of reading. I invite someone to confirm (or deny) them.
Assuming you are correct in your judgement of the length of the road, and assuming that you accelerated at maximum, you would have covered some 0.06 of a mile by the time you reached 60. The average speed would have been just over 30 for that time/distance.
You would then have had some 0.18 of a mile to travel at a very significantly higher speed to obtain an average over that distance of 64mph. You would have had to cover the remaining distance in some 6.5 seconds, giving a terminal speed after the first 7 seconds in excess of 120 miles per hour (assuming linear acceleration ... which is unlikely) to average 64 over 0.242 of a mile from a standing start.
As I say, these figures are rough calculations and subject to confirmation. It might be that the road is longer than you think; br interesting to check it though.
Streaky
The following figures are rounded for ease of reading. I invite someone to confirm (or deny) them.
Assuming you are correct in your judgement of the length of the road, and assuming that you accelerated at maximum, you would have covered some 0.06 of a mile by the time you reached 60. The average speed would have been just over 30 for that time/distance.
You would then have had some 0.18 of a mile to travel at a very significantly higher speed to obtain an average over that distance of 64mph. You would have had to cover the remaining distance in some 6.5 seconds, giving a terminal speed after the first 7 seconds in excess of 120 miles per hour (assuming linear acceleration ... which is unlikely) to average 64 over 0.242 of a mile from a standing start.
As I say, these figures are rough calculations and subject to confirmation. It might be that the road is longer than you think; br interesting to check it though.
Streaky
streaky said:
Something troubles me.
The following figures are rounded for ease of reading. I invite someone to confirm (or deny) them.
Assuming you are correct in your judgement of the length of the road, and assuming that you accelerated at maximum, you would have covered some 0.06 of a mile by the time you reached 60. The average speed would have been just over 30 for that time/distance.
You would then have had some 0.18 of a mile to travel at a very significantly higher speed to obtain an average over that distance of 64mph. You would have had to cover the remaining distance in some 6.5 seconds, giving a terminal speed after the first 7 seconds in excess of 120 miles per hour (assuming linear acceleration ... which is unlikely) to average 64 over 0.242 of a mile from a standing start.
As I say, these figures are rough calculations and subject to confirmation. It might be that the road is longer than you think; br interesting to check it though.
Streaky
Thanks for the calc's and the 120mph figure is what I'd have guessed. I roughly measured the road this morning using the car instruments, it's .3 mile from the lights to the scam and then 0.1 to the nsl. My thinking is that the average was calc'd way beyond the 40mph zone. Hmmmmm?
If you wanted to fight it, among other things you would need them to supply a witness statement confirming the point on the road at which they started recording and the point at which they finished. This might be available as a video. You could then calculate relative to the traffic signals stop line and the acceleration of your vehicle what initial and terminal velocities you must have achieved to give a 64mph average over the span of road. It would also be useful to learn whether you were seen to brake (which you must have done for the scamera you mentioned) ... and if so, at what point(s) on the road relative to the measured distance.
You will need to have very convincing figures though. The magistrates are quite likely to assume that a Griff can do 0-140 in 4 seconds.
If you did not exceed 100 from a standing start, it appears unlikely that your average could have been 64 over that distance. If you did top the ton, then it becomes moot and accepting a penalty for 64mph might well be the lesser evil.
It does appear that challenging the police evidence can produce positive results or the motorist. The CPS seem unwilling to spend too much public money prosecuting a case where the police evidence is strongly disputed and/or there is contradictory expert testimony. Police witnesses are somewhat used to their word being taken as gospel in Magistrates courts and when challenged regarding acceleration times, top speeds of both vehicles, exact positioning on the road, etc., can become confused and contradictory. Of course, you have to be careful not to give the game away, so it is vital to have a strategy that complies with disclosure rules and witness lists but leaves the door open to creating reasonable doubt in the minds of the magistrates by attacking the police evidence with supporting material.
Streaky [IANAL]
You will need to have very convincing figures though. The magistrates are quite likely to assume that a Griff can do 0-140 in 4 seconds.
If you did not exceed 100 from a standing start, it appears unlikely that your average could have been 64 over that distance. If you did top the ton, then it becomes moot and accepting a penalty for 64mph might well be the lesser evil.
It does appear that challenging the police evidence can produce positive results or the motorist. The CPS seem unwilling to spend too much public money prosecuting a case where the police evidence is strongly disputed and/or there is contradictory expert testimony. Police witnesses are somewhat used to their word being taken as gospel in Magistrates courts and when challenged regarding acceleration times, top speeds of both vehicles, exact positioning on the road, etc., can become confused and contradictory. Of course, you have to be careful not to give the game away, so it is vital to have a strategy that complies with disclosure rules and witness lists but leaves the door open to creating reasonable doubt in the minds of the magistrates by attacking the police evidence with supporting material.
Streaky [IANAL]
Thanks again for the comments.
The car was my Clio 182 and like I say it was new at the time so I kept within the recommended 3 - 3.5k rpm and never exceeded 85mph in it's running in period.
Any idea of what the distance travelled from a standing start to 60mph would be? Renault say that the car will do 60 in 7.1 seconds although I know I would be no where near that due to the car being run in.
The car was my Clio 182 and like I say it was new at the time so I kept within the recommended 3 - 3.5k rpm and never exceeded 85mph in it's running in period.
Any idea of what the distance travelled from a standing start to 60mph would be? Renault say that the car will do 60 in 7.1 seconds although I know I would be no where near that due to the car being run in.
Assuming the rate of acceleration is constant, distance travelled would be 95 metres.
Here goes ... 60mph = 26.8 metres / sec
v=u+at ... therefore 26.8 = a * 7.1
therefore a = 3.77 m/s/s
dropping that into s = ut + 1/2 * a * t * t
gives 1/2 * 3.77 * 7.1 * 7.1 = 95 metres ..
95 metres = 104 yards = 0.06 miles
The bit about assuming acceleration is constant is not true, the distance will be further than this.
Given the weight of the car, gear ratios, diff ratio, tyre size and power at different engine revs you could get a much more accurate answer ...
Here goes ... 60mph = 26.8 metres / sec
v=u+at ... therefore 26.8 = a * 7.1
therefore a = 3.77 m/s/s
dropping that into s = ut + 1/2 * a * t * t
gives 1/2 * 3.77 * 7.1 * 7.1 = 95 metres ..
95 metres = 104 yards = 0.06 miles
The bit about assuming acceleration is constant is not true, the distance will be further than this.
Given the weight of the car, gear ratios, diff ratio, tyre size and power at different engine revs you could get a much more accurate answer ...
steff said:
Doesnt the ecu record maximium engine speeds during the running in period?
Might help your cause.
Does it? Hmmmm?
scoule said:
Assuming the rate of acceleration is constant, distance travelled would be 95 metres.
Here goes ... 60mph = 26.8 metres / sec
v=u+at ... therefore 26.8 = a * 7.1
therefore a = 3.77 m/s/s
dropping that into s = ut + 1/2 * a * t * t
gives 1/2 * 3.77 * 7.1 * 7.1 = 95 metres ..
95 metres = 104 yards = 0.06 miles
The bit about assuming acceleration is constant is not true, the distance will be further than this.
Given the weight of the car, gear ratios, diff ratio, tyre size and power at different engine revs you could get a much more accurate answer ...
Interesting stuff. So assuming I hit 60 at .06 of a mile I averaged 64 between then and the speed camera, does seem a bit high when you take into account the braking for the scam.
So following my earlier workings (which also said 0.06 of a mile from standing start), 0.3 of a mile (the length of the road from stop line to scamera) MINUS 0.06 EQUALS 0.240 ... which is approximately the distance over which your average speed was measured.
If the police witness statement indicates the point on the road at which they started measuring is 0.6 of a mile past the stop line, then I'm afraid that there seems to be little in the way of argument.
Streaky
If the police witness statement indicates the point on the road at which they started measuring is 0.6 of a mile past the stop line, then I'm afraid that there seems to be little in the way of argument.
Streaky
streaky said:
So following my earlier workings (which also said 0.06 of a mile from standing start), 0.3 of a mile (the length of the road from stop line to scamera) MINUS 0.06 EQUALS 0.240 ... which is approximately the distance over which your average speed was measured.
If the police witness statement indicates the point on the road at which they started measuring is 0.6 of a mile past the stop line, then I'm afraid that there seems to be little in the way of argument.
Streaky
Yep you're right and so was your calc. Thanks for working it out and I guess now I'll have to suffer the poxy 3 points
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