Speedo accuracy - spin-off from QLD tolerances

[MAD]

I thought I'd start a new topic to see what views/facts/or otherwise are out there on this topic. I'm not going to cover every single detail, as I don't have the time or knowledge of all laws governing our lives, but I wanted to put forward some things that are common sense, and things that I know to be true and see where the discussion takes us.


Prior to 2006 the ADR requirements for speedometers fitted to the category of vehicles, that our family cars fall into, was that it could indicate a speed within +-10% of the actual speed, and were allowed to understate the actual vehicle speed.
100 could equal 90 or 110

In 2006 someone thought it was a great idea to disallow the understating of speedometers and change the tolerance based on a fandangled formula.

Originally Posted by MAD

ADR 18/03 says the speedo must read slower than actual speed and must fall within the following tolerance...

0 ≤ (V1 – V2) ≤ 0.1 V2 + 6 km/h; (V1 - indicated, V2 - actual)

Using this formula the maximum discrepancy between indicated and actual at the required test speeds can be as much as the following.

Indicated speed - actual speed - discrepancy
40 - 30 - 10
80 - 66 - 14
120 - 102 - 18

40 could equal 40 or 30
80 could equal 80 or 66
120 could equal 120 or 102



Now, on to the topic of things being illegal, and what constitutes breaking the law and being accountable, etc.

Ignorance is not an excuse.
We hear occasionally of a crime that has been committed where the person was found to have a skewed perception of right and wrong, to which a lesser penalty is delivered.
The lines between legal and illegal are very well defined in many instances. For example, you can't accidentally pre-meditate a murder, and you certainly couldn't accidentally hold-up a bank.
Knowing the difference between right and wrong and still choosing the latter is a willful disregard for the law.



On to our situation as motorists.

Exceeding the sign posted speed limit is illegal.
Maintaining your vehicle at a speed that is at or below the sign posted limit is the sole responsibility of the operator of the vehicle.
The tolerance given to drivers in VIC is 3km/h, plus the tolerance of the detection device. (2 or 3 km/h depending on the device)
Driving through a school zone at 120km/h is definitely breaking the law.

The best we can do as an operator of a piece of machinery, manufactured to a defined set of standards, is operate that piece of machinery based on the the standard of equipment fitted to that machine.



Let's start with a situation in a car manufactured pre-2006.
Zone - 110km/h
Indicated speed - 110km/h
Extremes of possible detected speeds - 99 or 121 km/h
Extremes of possible alleged speeds after device tolerance deduction - 96 or 118 km/h

The absolute best the owner/operator of this vehicle can do to drive within the posted limit is to base their speed on what the readouts supplied in that vehicle tell them. It is entirely possible that the driver of this vehicle could unknowingly exceed the posted speed limit.


Same situation, car made after 2006
Zone - 110km/h
Indicated speed - 110km/h
Extremes of possible detected speeds - 94 or 110 km/h (tolerance at 120km/h is 18km/h, so I'm assuming a little less at 110km/h and calling it 16km/h)
Extremes of possible alleged speeds after device tolerance deduction - 91 or 107 km/h


The absolute best the owner/operator of this vehicle can do to drive within the limits posted on the road is to base their speed on what the readouts supplied in that vehicle tell them. It is impossible for this driver to exceed the speed limit based on the readouts supplied in this vehicle.



Now, another couple of examples based on the same two cars above.

Vehicle 1 (pre-2006)
Zone - 110km/h
Indicated speed - 107km/h (is happy to drive a little slower to avoid a fine, but not so slow as to cause a major disruption)
Extremes of possible detected speeds - 96.3 or 117.7 km/h
Extremes of possible alleged speeds after device tolerance deduction - 93.3 or 115.3 km/h

A driver knowingly trying to avoid a fine has one delivered because the standards to which their vehicle was built allowed this to happen.



Vehicle 2 (post 2006)
Zone 110km/h
Indicated speed - 130km/h (wants to drive fast but doesn't want to lose license and 'knows' all speedos read little low)
Extremes of possible detected speeds - 112 or 130 km/h (assuming same 18km/h tolerance as at 120km/h)
Extremes of possible alleged speeds after device tolerance deduction - 109 or 127 km/h

The driver of this vehicle is knowingly choosing to speed, based on the readouts given in this vehicle, (willful disregard) yet it is entriely possible for this vehicles speed to be checked by a detection device and be found to fall within the legal limits of the traveling speed zone.



Let's look at some arguments to go with these situations.

Situation 1. No argument is recognised by the courts as the ADR's are not "Law"
How can this driver not be able to defend themselves when they were knowingly adhering to the posted speed limit?

Situation 2: No legal arguments needed, they're just an annoying slow driver that disrupts the flow of traffic on the <insert name here> Freeway.
Surely this situation has caused many accidents from the flow-on affects (most likely a nose-to-tail)

Situation 3:Very similar to that of situation 1, but slightly worse due the driver putting in extra effort to stay on the legal side of things.
How can this driver not be able to defend themselves when they were consciously driving below the posted limit.

Situation 4: Potentially no argument required as the driver believes he has escaped the long arm of the law and is thinks he is very clever because of it. So much so that he boasts to his friends that has done 15 trips from Melbourne to Kerang this year and always sets his cruise at 125km/h and has never been caught. He's even had police car's drive right past him and not been given a second look.
How is it ok for this driver to be knowingly breaking the law but it is impossible to be detected as such?


So it is not illegal to drive your car with an indicated speed higher than the posted limit, but it's possible to be fined while driving with an indicated speed lower than the posted limit.



Anyone see anything wrong with the picture here?

[XB GS 351 Coupe]

I just read all that and in the end it is the driver/owner/operator of the vehicles responsibility to ensure the speedo reads correctly.

For examle I own and drive several cars, and am well aware if my speedos read accurately, I recently fitted 33" mud tires to my 4x4 daily driver (32" standard, and yes it does see a fair bit of off roading, hence why the tyre upgrade), the first thing I did was check the speedo with my GPS, as I also do a lot of highway driving, the result was that the speedo now reads spot on (it did not before and I was aware of this also).

It's your vehicle so it is your responsibility to ensure it works correctly enabling you to drive legally.

Another thing you seem to have missed/ignored/unaware of, is that police radar equipment gives you a 'discount' on your actual speed, so the reading the officer gets already takes into account the possible worst case scenario equipment error, and adjusts it in your favour. So the radar will give you a lower reading than your actual speed no matter what.

I am not sure what the actual error percentage is and it is possibly different for different devices (hand held/vehicle mounted/camera etc), but lets say if the device has a worst case possible error of 5%, and you are traveling at an actual speed of 100km/hr, the speed that gets registered is only 95km/hr (based on a hypothetical 5%, it might only be 2% or what ever)

So if you are traveling at an actual speed of the speed limit you will never be booked (obviously) and even if you are travelling slightly over the limit, generally the speed detected will be lower than the actual speed you are travelling.

So personally I think people worry too much, just returned from a 250km drive and mainly used the cruise on 100km/hr in a 100 zone (most of the drive apart from a few towns I went through), seen a few highway cars cruising and they never even glanced at me sideways.

[MAD]

Originally Posted by XB GS 351 Coupe

I just read all that and in the end it is the driver/owner/operator of the vehicles responsibility to ensure the speedo reads correctly.

You know, I was going to pre-empt this statement cause I had a felling it would raise it's ugly head, but thought for some reason this time would be different. I should trust my instincts.

Ok, so you have a speedo, which was manufactured to read within +-10% of the actual speed. You take it to a certified, speedo certifier because you suspect it's reading a little low.
They give it the once over and find it is showing 100km/h when the actual speed is 105km/h. They look up the ADR, find it is within the 10% tolerance and put a great big smiley face stamp on the invoice.

It's your vehicle so it is your responsibility to ensure it works correctly enabling you to drive legally.

And when it's manufactured to a defined standard (ADR) you only have the tools you are given to do so.

Another thing you seem to have missed/ignored/unaware of, is that police radar equipment gives you a 'discount' on your actual speed, so the reading the officer gets already takes into account the possible worst case scenario equipment error, and adjusts it in your favour. So the radar will give you a lower reading than your actual speed no matter what.

So you didn't read my post at all then?

Originally Posted by MAD

The tolerance given to drivers in VIC is 3km/h, plus the tolerance of the detection device. (2 or 3 km/h depending on the device)

[MAD]

I know what the thread title says, but I actually wanted this thread to be more about the consequences of speedo accuracy, and the intent behind a broken law.

Going by the ADR's, it is 100% possible for a person with the intent to speed, to actually avoid punishment because they weren't actually breaking the law, even though they thought they were.
And, it is 100% possible for a person that was consciously erring on the side of caution to be sent a bill for $165 and 1 demerit point, because it turns out that they were breaking the law even though for all intents and purposes, their car told them otherwise.

[excopau]

So I get an work vehicle, do I go get it tested so I know what it is out?? This is such bull crap, dodgy rules

[grandpa_spec_F6]

Comprehensive post.... but did you miss the part about the police always being right?
Mate copped a fine, he disputed it with the above in a similar manner.... thrown out because complaints cop was also the one who issued the ticket.

[2011G6E]

That's what annoys the hell out of me..."it's your car so it's up to you to double check the speedo".

Bugger off...I shouldn't have to. Why do I have to go and shell out for a GPS unit to double check the factories work? I bought the car in good faith from the manufacturer and should be able to drive to an indicated speed and that should be that...no further argument would be allowed in a sane and fair society...but when we talk about speed limits, nothing is fair and sane about it.

A cop once told me "simply go and get your speedo recalibrated".

"Simply..."

I did actually ring a VDO shop to enquire about the cost of doing so, just out of curiosity, and the guy hummed and hahhed for a while, and said he wasn't absolutely sure, but you'd want to be sitting down when they told you the price...if it was at all possible in the first place.

If the laws were fair, if you were sitting on an indicated 100 in a standard car, then that should be that...so what if you're a few k's over or under. But that's not how the law works. If you're doing 100kph or 102kph, if you hit something the outcome is identical. Even up to 110 the difference would be virtually unmeasurable in terms of impacts.

As said above..."the copper is always right". They count on no one taking a couple of days of work with no pay and going to court to try and fight a small fine...and those small fines must sure add up. Factor in getting a photo two weeks later and trying to remember exactly how fast you'd been going at the moment the picture was taken, and 99.9% of people will just shrug, assume the wonderful magical infallible machine must be right, and pay up. They count on this too.

Hell, even those most horrifying murderous child molester is presumed innocent until proven guilty beyond any possible shadow of a doubt...but go 5kph over the speed limit unknowingly, and you're a worse scourge than Hitler...

[jpd80]

Under the law, it's the driver/owner's responsibility to ensure that the maximum speed is not exceeded.
To do so means that you should ensure that your speedo is reading accurately or slightly fast for a comfort
or safety margin...or do what I do and check it with your navman, Garmin or Tom tom..

[prydey]

and although the ADR rule prior to 2006 was +/- 10%, the reality is most cars would be fine. it would be a very small minority that do actually understate the actual road speed.

of course there will be many replies stating how they know someone who had x car and it had a speedo that under read. if every single member on the forum knew of one example, it would still be a minority!!

[jpd80]

Yeah, I remember chaecking new XE, XF, EB, EF and BAs over a measured kilometre
and seeing that the time was pretty much dead on accurate for 100 kph.

I remeber something abot Ford and Holden making bigger strides with
accuracy after speed cameras came in..

[Yellow_Festiva]

Originally Posted by excopau

So I get an work vehicle, do I go get it tested so I know what it is out?? This is such bull crap, dodgy rules

There was a case in NSW last year where an employee was driving a work van around. He didn't know the boss had wound back the clock in the van 15 minutes so when it was 10am, in reality it was 9:45am. This was done so workers got to appointments on time or just prior.

The guy got done in a school zone a few minutes prior to the cut off, and because he didn't know the clock was out it went to court and the fine was removed. The boss stepped in for him and explained what happened...

On the other hand, a friend of mine was asked by his manager to drive him around for work as the manager got done drink driving and lost his licence. Cops pulled him over and fined him because the car he was driving wasn't registered (managers car, not his). Cop didn't care what story they gave, mate wore the fine and didn't persue it as he parted with the job soon after and knew the boss wasn't going to help him out with the case.

In terms of speedo accuracy... is the tolerance +/- or is it just to read under all the time??

With the Focus, well worn standard factory tyres read about 6% below indicated. I think 100 indicated was around 94km on the GPS.

I put on a larger profile tyre and the speedo was spot on accurate, so there is even room for movement if you go for a larger wheel / tyre combo.

[prydey]

Originally Posted by Yellow_Festiva

In terms of speedo accuracy... is the tolerance +/- or is it just to read under all the time??

fairly well covered in the OP. prior to 2006 cars only needed to be accurate +/- 10%

Originally Posted by Yellow_Festiva

I put on a larger profile tyre and the speedo was spot on accurate, so there is even room for movement if you go for a larger wheel / tyre combo.

if you modify your car (including different tyres from manufacturers spec) then the onus is 100% on you, regardless of year of manufacture of the car.

[jpd80]

Check your speed first.

Find the measured kilometre marks, time your car over it.
At 110 kph it should be 33 seconds,
At 100 kph it should be 36 seconds..

[Yellow_Festiva]

Originally Posted by jpd80

Check your speed first.

Find the measured kilometre marks, time your car over it.
At 110 kph it should be 33 seconds,
At 100 kph it should be 36 seconds..

Even that will have a decent margin of error...

I think the best way is to use a GPS and memorise the error. I knew that at an indicated 60 I was doing 57 and that at an indicated 110 I was doing around 104.

Myself and my wife knew that if we were driving and stuck to the limit we would be slightly under, and that if we were going somewhere on the freeway and were in a bit of a rush we could go a few km over and still be fine.

[T4ME]

What if the GPS is not working correctly who will one blame then?

[Yellow_Festiva]

Originally Posted by T4ME

What if the GPS is not working correctly who will one blame then?

[jpd80]

Originally Posted by Yellow_Festiva

Even that will have a decent margin of error... .

not as much as you'd think every full second is worth 3 kph, I've found it pretty accurate.

I think the best way is to use a GPS and memorise the error. I knew that at an indicated 60 I was doing 57 and that at an indicated 110 I was doing around 104.

Myself and my wife knew that if we were driving and stuck to the limit we would be slightly under, and that if we were going somewhere on the freeway and were in a bit of a rush we could go a few km over and still be fine.

I mentioned that above, most people now have sat nav so the answer is with us already.

[gtxb67]

i drive/drove a 73 ford fairmont with larger wheels
a 91 mazda 121
a 09 toyota rav4
an 84 ford telstar
a 91 ford fairlaine
a 75 datsun

and i have not had problems in the most over regulated state the world has ever seen

it ain't hard - if you have an older car have the speedo checked if it worries you so much
if you have a newer car, then keep the needle on the speed limit and you will be going slightly slower . . . . too easy; or so i thought
or just look for the cameras - in the country's finest state they are easy to see, and yet, many still get pinged

[MAD]

Originally Posted by prydey

and although the ADR rule prior to 2006 was +/- 10%, the reality is most cars would be fine. it would be a very small minority that do actually understate the actual road speed.

of course there will be many replies stating how they know someone who had x car and it had a speedo that under read. if every single member on the forum knew of one example, it would still be a minority!!

I have never heard of it actually happening to someone, and it may be the case that most cars would read under, but none-the-less, it is written in black and white what the allowable tolerances were, and they are being totally ignored.
Whether that tolerances was in place to allow for the life of the item, or whether it was common sense knowing that nothing's perfect, I don't know.

[MAD]

Getting back on to the other point, the ability to intentionally break the law and get away with it. What's the views there?

Do you re-label you're speedo to be accurate? Do you rely on your memory to remember that 125km/h indicated is 110km/h? What if you forget sit on 132km/h like your other car, and you're actually doing 117km/h and get caught? Do you explain to the officer that your speedo reads low and you forgot which car you were driving so you were sitting on an indicated 132km/h when you should have been on 125km/h?

Don't think that argument would go down to well.


It is totally ridiculous to even think you should go out and get your brand new speedo verified before you go off gallivanting around and driving to the speeds shown on the dashboard.

[prydey]

i think you are getting a bit worked up over a 'theoretical' argument.

the reality is most cars speedo's would be reading up to the right speed, but rarely over it.

if someone thinks they are speeding because the dial in front of them says they are, but in reality they aren't, then technically they aren't actually speeding, whether they intend to or not.

[MAD]

Originally Posted by prydey

i think you are getting a bit worked up over a 'theoretical' argument.

the reality is most cars speedo's would be reading up to the right speed, but rarely over it.

if someone thinks they are speeding because the dial in front of them says they are, but in reality they aren't, then technically they aren't actually speeding, whether they intend to or not.

Don't worry bud, I'm not getting worked up.
I simply have in my hands hard and fast, black and white facts that cannot be argued away with a rational thought.

It's a topic that popped in to my head and I thought it had some interesting points regarding intention, and the lack of ability to defend against something even when you have black and white facts on your side.

But just to correct something, this is not a theoretical argument, it is 100% possible on all accounts that I have given.


What if someone robbed a bank and in the course fired a few shots in to the teller's chest, but it was unknown to the robber that the teller was wearing a bullet proof vest? Does intent come in to play when sentencing even though the teller survived? <- I would really like to know the answer to this. I wouldn't know where to begin researching the laws around this.

[prydey]

possible - yes, probable? no.

if anyone is worried, gps devices are readily available (most phones have gps which can give you a speed read out) so its not that hard to work out if your car is accurate or not.

[EgoFG]

I am guessing that there is almost no deaths or hospitalisations from accidents where the primary cause was travelling less than 10% over the posted speed limits.

[MAD]

If GPS is so good, and so cheap, why aren't cars fitted with GPS based speedos from the factory?

I just did a little google search on Subaru and Toyota speedo accuracy, as I had heard these were quite inaccurate. Lots of results, and lots of annoyance from the owners.
It seemed a common trend that they investigated the issue after finding they were always being overtaken, and why there was always a long line of cars behind them.

[flappist]

Of course it is not appropriate to assume that the purpose of law is to assist people rather than punish them.....

I am sure all these "date rapes" that are featured on ACA could completely avoided if every girl who goes out to a pub/nightclub takes with her a mass spectrometer to test each drink.........

The more I read these threads the more I believe that the main focus of those who push the zero tolaranece agenda has nothing to do with speed or safety, it is purely ABSOLUTE OBEDIENCE.

"If she just did what I told her I would not have to beat her" is NEVER valid EVER but the mindset behind it still abounds......

[MAD]

Too bloody true. It's like this was the sneaky back door to forcefully slow people down.
The other option would be to increase accuracy, and lower speed zones as desired. But you can't hide that and people would complain.



Another thing I've just realised, is that I can be fined for having headlights that do not meet an ADR, but I can't use an ADR as a defense when everything is compliant.

[TheSneakiness]

As per the other thread where this was discussed whether purposefully or not Mitsubishi seem to always be at the maximum tolerance under the indicated speed.

For example, indicated 60km/h is actually 56km/h (measured GPS). This descrepancy increases with indicated speed.

I could either increase tyre sizing at greater cost for me, or simply go off what I've measured over long distances on the GPS compared to what the speedo shows.

[gtxb67]

Originally Posted by MAD

It's like this was the sneaky back door to forcefully slow people down.

the last thing they want is for people to slow down - then their revenue stream dries up and they need another tax to balance the books

[JC]

If you were in a pre 2006 car, and you got pulled over for doing 117 in a 110 zone, but you say you were doing 110, then the police may test your car. If you have the correct size tryres etc fitted, then they may let you off with an official warning, but don't expect to be let off a second time (depends on the copper, though).