speeding offences

[doug3030]

Hi doug 3030,
Has it occurred to you that may be it it your GPS that is telling porkies and not all those speedos?
Regards

car 1 - gps number 1
car 2 - gps number 1 and number 2 - readings exactly the same
Car 3 - gps number 2 and 3 - readings exactly the same

The way I have measured the speed by GPS leaves little scope for error. All three vehicles have cruise control. measurement was made on a straight flat road with cruise control set for at least 2 minutes to allow for the setting to stabilize.

It is no surprise that under those conditions there is no difference between the gps readings, assuming you know how a GPS works.

Cheers

Doug

[A Duke]

Hi Doug,
Thanks for the answer, I Was not clear that you had used more than one GPS.
No I do not really know how a GPS works I usually know where I am going and have not needed one yet.
Regards

[Chris Parks]

How many satellites did you get and what was the GPS, a phone? if it was a phone it only has a resolution of 1 or 2hz a second and that is hit and miss for accuracy. The loggers we use work at 10hz a second and I do not trust the accuracy at all, huge lag at all times against a physical speed sensor. We know it's inaccurate because the difference between the two speeds shown varies at the same physical speed, if it were the same each time then I would question it.

[smidsy]

What gets me about the phone laws is that it's illegal to use a phone while driving, but I can smoke or scoff a burger while driving and talking to a passenger - carrying on a conversation with one hand off the wheel, the same as if I was on the phone.
If I get in a situation where I need both hands for the wheel I would drop the phone without a second thought - but I'm going to have second, third and fourth thoughts about where I drop a cig or a burger.
And before you all flame me I am pointing this out, I dont use my phone when driving, I usually have the radio too loud to hear it, but rarely answer the silly thing when it does ring whether I'm driving or not.

As for speedo accuracy, I just found the ADR's and for 2006 & beyond they state speedo's cannot read low but can read high - cars & trucks +6kph, mopeds +4kph and motorbikes +8kph.
My 04 BA Falcon is thus outside the rules, when I have the GPS on the speedo reads about 8k less than the GPS.

[Big Shed]

The thing that I can't understand about the mobile phone laws is that you can't talk on your mobile but how many taxis, trucks and caravans (dare I say police cars!) have a 2 way radio of some type and they are happily using these all day every day?

If we are going to be consistent (heaven forbid) then the use of those should be banned as well.

[BobL]

What gets me about the phone laws is that it's illegal to use a phone while driving, but I can smoke or scoff a burger while driving and talking to a passenger - carrying on a conversation with one hand off the wheel, the same as if I was on the phone.
If I get in a situation where I need both hands for the wheel I would drop the phone without a second thought - but I'm going to have second, third and fourth thoughts about where I drop a cig or a burger.

Unless you train yourself to drop it, you probably won't drop it. anyway by the time you drop it, it might be too late.

It was interesting to see that the guy that ran into me did not drop his phone and tried to get out of my way at the last minute still holding his mobile. He even got out of his car still holding it.

[doug3030]

How many satellites did you get and what was the GPS, a phone? if it was a phone it only has a resolution of 1 or 2hz a second and that is hit and miss for accuracy. The loggers we use work at 10hz a second and I do not trust the accuracy at all, huge lag at all times against a physical speed sensor. We know it's inaccurate because the difference between the two speeds shown varies at the same physical speed, if it were the same each time then I would question it.

The speed is calculated continuously by the GPS several times a second. The speed it displays is a moving average of the speeds measured over a predetermined time. This is done so that the displays a little bit more steady and does not change with every reading the GPS measures. The longer the timeframe of the moving average the longer the "lag" period in displaying a change of speed. If the physical speed sensor is displaying realtime then this is why you are experiencing the lag on the GPS display.

When I have made comparisons between the speedo and the displayed speed on the GPS, the car has been in cruise control on a flat straight road with the GPS display reading the same figure for quite a while, thus neutralising the effects of the lag caused by the moving average. It was not a phone that I used and I would have to switch to a different screen to see the number of satellites, and I am not going to do that at 100km/hr.

As for speedo accuracy, I just found the ADR's and for 2006 & beyond they state speedo's cannot read low but can read high - cars & trucks +6kph, mopeds +4kph and motorbikes +8kph.
My 04 BA Falcon is thus outside the rules, when I have the GPS on the speedo reads about 8k less than the GPS.

My last three cars mentioned above that all have speedos reading low were 1998, 2002 and 2003 and thus not covered by this rule either, but there are still a hell of a lot of cars out there that are completely legal whose drivers can be booked for innocently trusting the accuracy of their speedo.

Cheers

Doug

[FenceFurniture]

The thing that I can't understand about the mobile phone laws is that you can't talk on your mobile but how many taxis, trucks and caravans (dare I say police cars!) have a 2 way radio of some type and they are happily using these all day every day?

If we are going to be consistent (heaven forbid) then the use of those should be banned as well.

It was explained to me by a copper, sometime in the 90s, that the NSW offence was "not having two hands on the wheel" when I asked about the legalilty of the CB radio usage - so yes, that is illegal as well here. That may have changed or been reworded, I don't know.

Police are exempt from that in just the same way that they can do an otherwise illegal u-Turn to chase a car.

Heh, heh. However, outside Sutherland Courts one day (again in the 90s) a copper pulled up and parked, and he was on his phone all that time. I waited until he got out and said "I just got booked for that the other day" and to my surprise he said "Ok,OK, you got me, I shouldn't have been doing it. We've just been on a drug bust" and he held up a bag of an odd green looking herb (which I of course didn't recognise). Perhaps that was before they were made exempt from the law (for the phone thing )?

[mark david]

Watch the beginning of the movie Wolf Creek 2

[doug3030]

The speed is calculated continuously by the GPS several times a second. The speed it displays is a moving average of the speeds measured over a predetermined time. This is done so that the displays a little bit more steady and does not change with every reading the GPS measures. The longer the timeframe of the moving average the longer the "lag" period in displaying a change of speed. If the physical speed sensor is displaying realtime then this is why you are experiencing the lag on the GPS display.

I just thought that I might elaborate a bit more on how the GPS works in this regard in case anyone is interested.

When a GPS works out your location it could be off by several metres. As I said earlier, the unit calculates your speed several times a second. Now given that it is not reading your exact location each time, say you are travelling at 10 metres per second (36 km/hr).

The GPS makes say 10 readings in the first second all finding your position within 2 metres of accuracy. Lets say they are:

8 metres/sec
9.5 metres/sec
11 metres/sec
10.8 metres/sec
8.7 metres/sec
12 metres/sec
10.5 metres/sec
9 metres/sec
9.2 metres/sec
11.3 metres/sec

If the GPS did not work on a moving average, the displayed speed would be flicking between 28.8 and 43.2 km/hr so often that you could not read it and the data would be of little use anyway. If the display is programmed to show a moving average of the speeds calculated over the last second it will display 36.0 km/hr, because it has averaged out its own inaccuracies of measurements (this is of course simplified), there are often higher or lower biases in the data collected.

It is therefore a juggling act to make the timeframe of the moving average long enough to give a satisfactory reading but not so long as to produce too much lag.

Most GPS users would have experienced coming to a stop at a red light and looking at the GPS for the distance to the next turn and seeing that the car is still supposedly traveling at say 8 km/hr, then 4 km/hr then finally 0 km/hr as the moving average finally catches up with reality. This is why you see that.

When you drive under an overpass or bridge, the GPS will miss several signals from the satellites, which can mess up the moving average, so it often happens that as you emerge from under the bridge and the satellite signals are again being received, the GPS misinterprets the data by thinking that you have traveled further than you really have in the time elapsed and momentarily displays a high reading for your speed.

Many people, particularly those with knowledge of conventional navigation, believe that the GPS determines your position by measuring the direction to the satellites (like performing a resection) but this is not the case. The GPS actually works on calculating the distance from the satellites by calculating the time elapsed from the transmission of the signal until it is received. The satellites are geo-stationary and their locations are programmed into the calculations the GPS makes. It determines your location by finding the only point on the surface of the earth that is the required distance from a minimum of three measurements from different satellites rather than a direction to them.

My GPS goes stupid in the Melbourne CBD because the signals reflect off the glass sides of the highrise buildings, causing it to receive conflicting data, such as the same signal from the same satellite received a split second later than another identical signal, as one or more signals has reflected off a building.

All of the above is a very simplistic version of how it works. If anyone wants to elaborate, feel free, but I do not want to make it any more confusing than it already is.

Cheers

Doug

[Chris Parks]

The speed is calculated continuously by the GPS several times a second.

Cheers

Doug

Yes, ours is 10 times per second, the average GPS used in cars is about 2 times per second at best. We have experimented with twenty times a second but it gave no better results so it was ditched. Everyone gets hung up on GPS accuracy and I am far from an expert, more of an observer and serious user for sport purposes over the last six or seven years. We use it for lap times as well but again it never gives the same results as a physical transponder, close but never the same. If it were as accurate as some would want to believe the F1 teams of this world would use it and they don't.

[doug3030]

[QUOTE]

...Remember the slogan "Speed Cameras Save Lives". Can anyone give me the name of ONE person whose life was saved by a speed camera?

That's just as stupid a question. However, most of us can give you the names of plenty of people who've been killed by drivers speeding or talking on mobile phones, or both.

It looks like I am not alone with my thinking

www.caradvice.com.au/332771/are-speed-cameras-killing-us-the-stats-say-yes/

Are speed cameras killing us? The stats say yes
Read more at http://www.caradvice.com.au/332771/a...iUDf3s9RHv8.99

To quote a couple of relevant paragraphs:

The unfortunate reality of speed camera-biased enforcement can be demonstrated with the tragic death of pedestrian Anthony Parsons and husband and wife Savva and Ismini Menelaou, who were passengers in a Ford Falcon struck at the intersection of Warrigal and Dandenong roads in Oakleigh, Victoria last year.
Brazilian national Nei Lima DaCosta was high on ice and drove through one fixed speed camera at 30km/h over the speed limit minutes before careering through the intersection of Warrigal and Dandenong roads at 120km/h (40km/h over the speed limit) through another speed and red light camera. He killed three innocent people. These two cameras did nothing to help save the lives of three innocent people.

and

Those people that use the idiom “don’t speed and you won’t get caught” simply don’t understand the reality of driving safely. If I had the preference of watching the road or my speedometer, I know which one I would choose.

The statistics presented in the article clearly show that the only thing that the presence of speed cameras have changed is the amount of revenue the government gets.

Have a read of the article and the comments that follow. Note how quickly anyone who suggests that speed cameras are effective in lowering the road toll are shot to pieces. They are revenue raising - pure and simple.

Cheers

Doug

EDIT: or have a look at this: http://aca.ninemsn.com.au/article/8954478/drivers-fined-for-low-level-speeding

[BobL]

Have a read of the article and the comments that follow. Note how quickly anyone who suggests that speed cameras are effective in lowering the road toll are shot to pieces. They are revenue raising - pure and simple.

I had a read, a pretty shallow analysis in my view. The claim that camera actually cause deaths is fanciful and typical of the sorts of analysis done by reporters these days. Take a couple of stats and makes all sorts of claims. Increasing hospital length stays could be saying more about the over servicing that typically happens in the health system more than it does about car accidents.

The sorts of people I would take more notice of in this area are a professional motor vehicle accident data analysts. I happened to know couple of people that work in this field, these people have higher degrees in Mathematics, statistics and public health.and they have been working in this area for more than 20 years. Their view is that untangling road accident statistics and causes is very difficult and coming up with meaningful relationships is even harder - given the numbers of variables involves puts it in the "Global warming" category of toughness or maybe even harder.

The relationships involved between motor vehicle accident deaths and injuries are neither simple and most definitely "non-linear" and often counter intuitive - just because something goes up or down doesn't mean that something goes up/down in proportion. There's a fair bit of estimating (yes guessing) involved with all this but the last people I would leave the guessing to are average joe's including reporters.

Personally I don't really care if it's just a revenue raising exercise.
If we have to tax someone then speeders are OMHO as good a target as most and maybe even better than most other taxes i.e. you pay for the privilege.
If the choice is to raise income tax, or raise GST, then I would favour a rise in speeding fines.

I do agree with a couple of things in that article at the end where he talks about stopping more people for drug detection and better driver education. One piece of education that needs to come through is that drivers need to realise that a motor vehicle is not a piece of mobile private property and neither is the space around their vehicle.

[BobL]

OK - I'll play reporter with accident stats.

If speed cameras cause accidents/deaths then the states with the greatest number of cameras per capita/vehicle/km etc should have the highest deaths per capita/vehicle/km etc.

Now I haven't personally seen the data . . . . . hang on that's not what a reporter would say.

Ahemmm . . .. the data clearly shows that the states with the most cameras per capita/vehicle/km etc have the lowest deaths per capita/vehicle/km etc.

Well, this is the excuse the WA government are using to get more cameras.

Personally I just think we have more bogans and hoons per capita/vehicle/km etc

[doug3030]

If the choice is to raise income tax, or raise GST, then I would favour a rise in speeding fines.

Thanks for your considered opinion Bob.

I just found this online, It is the Victorian version but I doubt the others are much different: file:///C:/Users/Doug/Desktop/VicPol-Mobile-Digital-Speed-Camera-Policy.pdf

Have a look at this bit on page 4:

Where possible, sites in both metropolitan areas and regional locations should be definedby the closest intersecting streets on either side of the site with the entire length of a sitebeing kept to a minimum. In rural areas the site length should be no greater than 5kilometres. Speed zone signs should not be used to define a site boundary. This will makeit easier for motorists to determine (when referring to the infringement notice) where thealleged offence occurred.

WT?, they want you to pay the fine for speeding but they are doing everything they can to conceal from you exactly where it happened?

then add in this:

Criteria 5
Careful background evaluation of each site shall be conducted for any sources of reflectionlocated in or near the radar beam position including;
a) The possibility of vehicles entering or leaving intersections, or travelling along service roads;
b) Pole mounted electricity supply transformers;
c) Mobile road safety camera set-ups should not include sites where there are train lines whichare obscured by dense foliage – such that the MRSCO is unable to determine whether a trainis present at the time a target vehicle is detected:d) Tram and train lines: Other than (c) above, the MRSCO must indicate on the Incident Log ofthe Camera Operator’s Set-up notes the times that any images are taken where a tram or trainis within the area of the beam;
Note: Where this occurrence is frequent, the site maybe deemed as permanentlyunsuitable or in the case of trains, restricted to operate on the opposite side of the roadway(where the train lines would be behind the speed camera)
e) Metal signs - house sale / auction signs and similar;
f) Centre strip traffic signs such as No U Turn, No Right / Left Turn, Keep Left, posted speedlimit signs and large advisory cross street signs;
g) Armco road barriers or chevron signing;
h) Metal bus stop shelters, public telephone booths, Australia Post letterboxes;
i) Sheet metal garage doors, fences, factory walls and fencing structures which comprise ofclosely spaced (10cm or less) vertical metal bars.
j) Brick/Masonry StructuresThese structures are divided into two parts;ƒ Masonry structures that are over one metre in height and;ƒ Very tall masonry structures such as factory walls.

If they not only will tell you exactly where the infringement allegedly occurred but also are deliberately conspiring to hide this information, how can you check up that they have complied with the rules?

And then there is this:

Criteria 4

A site shall not be on or near an overpass, or facing any elevated adjacent road (entry orexit ramp) that may carry traffic through or near the radar beam area.

Last year in September I was booked for doing 101 km/hr in a 100 km/hr zone for a cost of $185 and one demerit point and the location was given as "Westgate Freeway, vicinity of Palmers Rd OVERPASS".

Had I read this manual at the time I would have challenged it. Tell me that is not blatant revenue raising and nothing else.

Cheers

Doug

EDIT: I forgot to mention that when I was booked fo r101 in a 100 zone my "LEGAL: speedo for a pre-2006 vehicle would have been reading 97 - 98 km/hr.