speeding and speed

[olfella]

I have a GPS hardfixed in my BA and therefore hardly ever lookat the speedo because I know it reads low. When passing speed traps etc I always use the GPS and have never been pulled over. What I am getting at is I am told the speed readout on the GPS was most accurate and therefore I take it as gospel.

Now on a recent trip in Vic, I went under one of those check your speed thingos and I was doing spot on 110 on the GPS. The speed thingo said I was only doing 107!! meanwhile my speedo is reading up in the 120 mark.

My point in raising this is what sort of defence does anyone have when pulled over to be told they were 2-4 k over the limit. What makes the coppers equipment so accurate and why the hell cant they put that in everyones car so we all know how fast we really are going?

[AUXRVIII]

On a recent trip to Bathurst I went throuh the speed check at 3 different locations & got 3 different reading for the same indicated speed. At one location I was in the right hand lane & a vehicle was in the left lane was sitting on exacly the same speed as I & his speed check came up 2km/h slower than mine.

[VilkasBAMIIXR6T]

Originally Posted by olfella

I have a GPS hardfixed in my BA and therefore hardly ever lookat the speedo because I know it reads low. When passing speed traps etc I always use the GPS and have never been pulled over. What I am getting at is I am told the speed readout on the GPS was most accurate and therefore I take it as gospel.

Now on a recent trip in Vic, I went under one of those check your speed thingos and I was doing spot on 110 on the GPS. The speed thingo said I was only doing 107!! meanwhile my speedo is reading up in the 120 mark.

My point in raising this is what sort of defence does anyone have when pulled over to be told they were 2-4 k over the limit. What makes the coppers equipment so accurate and why the hell cant they put that in everyones car so we all know how fast we really are going?

When you contest any ticket relating to specialised equipment such as evidential breath test machines, speed cameras, radar/lasers, you need an expert witness to be able to attack the credibility of the machine. All you need to do is create "reasonable" doubt and you will win your matter. If you cannot attack the working of the machine hit them at the process of setting it up etc. :

[GT595]

Good point - I use the Sat Nav speedo all the time myself.......I think the cops wont really look twice @ 4-7 over when travelling @100 - 110km/h (probably will in Vic!!!). They will tend to get you for that minimal figure @ far lower speeds where your sat nav and speedo are less than 2km/h apart - school zones and 50 areas..... As far as I know they use the laser technology that bounces its signal from a moving object dont know how you would adapt that to a car to create the speed reading..... Just keep those eyes peeled out in front at all times!!!

[CarBroker]

Originally Posted by olfella

...What makes the coppers equipment so accurate and why the hell cant they put that in everyones car so we all know how fast we really are going?

The cops recalibrate their equipment regularly. They have paperwork showing when the last calibration was done. If calibration is not done for a long time, it goes out of whack. From memory, that's what happened to the speed cameras on the Western Ring Road in Melbourne (and ended up costing the VIC gov't about $19M in refunds).
It is easier for the manufacturers to overestimate the speedo speed. Except on cop cars, where the speedos are calibratable (if that's a word). I used to work at Ford (for a while on the instrument panel assembly) and I remember we used special "police clusters" for cop cars.

[BA_Turbs]

To win a contested speeding ticket you need to PROVE that the radar, or far more likely, the laser was wrong. Not easy.

As far as "What makes the coppers equipment so accurate and why the hell cant they put that in everyones car", its entirely different technology.

Even the GPS, in non-military applications, can have error.

I generally just drive "sensibly" and have had a couple of tickets since I've had my licence (from speed cameras, not police). I was speeding, so I didn't sook. If I want something done about our funking stupid speed laws here in Victoria, I'll write to my MP instead of whinging on the internet, which achieves nothing, like so many other people seem to do.

olfella, this above paragraph is not at all directed at you by the way. For your purposes, the GPS will give you the most accurate reading, given that the speed checks are spread far and wide.

[vztrt]

Originally Posted by BA_Turbs

Even the GPS, in non-military applications, can have error.

Thats right, GPS has errors inputted intentionally for no-military.

Nothing is 100% accurate. But the police will leave you alone (I havent had trouble) for being 5kph over the limit.

[CarBroker]

Originally Posted by vztrt

Thats right, GPS has errors inputted intentionally for no-military.

Not anymore (since May 2000)

See this link

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[vztrt]

Originally Posted by CarBroker

Not anymore (since May 2000)

See this link

Yeah I heard somthing about that, even so there still is a tolerance with GPS.

[b2tf]

What i cant work out is how 3 different items are giving you 3 different readings that are so far out from each other, 120 on speedo and 110 in GPS seems a bit odd to me.

Speaking to a NSW HWP officer a while back he reckoned the typical tolerance in NSW is 10% + 3. So if you were in a 100 zone, you could theoretically get away with up to about 113. Of course that depends on the individual cop who gets you though.

[CarBroker]

Originally Posted by back2thefutura

What i cant work out is how 3 different items are giving you 3 different readings that are so far out from each other, 120 on speedo and 110 in GPS seems a bit odd to me.

I agree. As vztrt points out, there are tolerances in GPS as well, but I think speedos are showing way too high. In my car, I know (based on the Geloong Freeway speed check) that 105 is 100. I think that's too far out.

It causes a problem because it means traffic is not moving at a constant speed. Small speed differentials means tailgating and road rage.

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[JC]

The GPS errors that used to be built in are in relation to position, not speed. GPS speed reading is the most accurate.

An error of 5km/h at 100 is within ADRs - the ADRs say 10% is OK, yet Vic Police tolerance is 3km/h Or less (ie 3% at 100km/h).

The speed reading things over the highways are indicative only. You cannot use them as a defence if caught speeding, and most of them will only read up to 117 (that was introduced as people were using them to find out the real top speed of their cars).

[bindi]

Originally Posted by olfella

I have a GPS hardfixed in my BA and therefore hardly ever lookat the speedo because I know it reads low.

IMHO this may be a bad habit to get into... I'd always be looking at the speedo anyway. Because there may be a time when you need to drive an older car with no GPS.

It's like people who can drive both an auto and a manual. They get into the habit of using their left foot to work the brake in their auto over the years. The day they get back into a manual and go to stop in an emergency situation... they may end up dead cos they used the clutch to try and stop.

May not happen but you can't predict the future.

Try and stay in good habits. I recently realised that these days, I'm not coming to a complete stop at a stop sign. Now I make a concerted effort to get back into the habit. Don't fancy a fine

[outback_ute]

The readings on those highway speed check signs are not worth the paper they're written on

(ps they are not written on paper - therefore worth nothing)

[GTP 320]

Originally Posted by outback_ute

The readings on those highway speed check signs are not worth the paper they're written on

(ps they are not written on paper - therefore worth nothing)

Yes there only a guidence to what speed you may be doing,but they are not accurate.
Cheers John

[gozza]

Originally Posted by back2thefutura

What i cant work out is how 3 different items are giving you 3 different readings that are so far out from each other, 120 on speedo and 110 in GPS seems a bit odd to me.

Speaking to a NSW HWP officer a while back he reckoned the typical tolerance in NSW is 10% + 3. So if you were in a 100 zone, you could theoretically get away with up to about 113. Of course that depends on the individual cop who gets you though.

i live in qld and i was told by our school based officer that the speedos tolerance was 11 k's on all speed limits....no percentage.....

[Luke..]

so that means if your caught doing 51 in a school zone, or 61 in a 50 zone u wont g et booked? yea right.
Luke,

[GasoLane]

The speedo reading in most of the cars that I've owned over the years -lots- has been about 10% fast. IE:speedo shows 110, actual speed 100.

As for the Vic overhead readouts... I drive a Semi, when I used to go under the one at Beverage the prime mover would show 103kmh but the second trailer was seemingly only doing 96! I often wondered if I should stop at Seymour to wait for my second trailer to catch me up !!

[benXaGt]

My car sits on 60mph when im going down the freeway every1 around me is going slower. Could it be somthing that there putting the new cars speedos out by 10 km/h when they build them?

[FordFan86]

Those with older cars or ones that have had a few mods, such as diff ratio changes or running tyres that were not factory spec will also have their speedo out by a few kilometres. This is a very useful tool, see halfway down the page.
http://www.fordmods.com/forums/documents.php?doc=30

[Walkinshaw]

Originally Posted by bindi

IMHO this may be a bad habit to get into... I'd always be looking at the speedo anyway. Because there may be a time when you need to drive an older car with no GPS.

It's like people who can drive both an auto and a manual. They get into the habit of using their left foot to work the brake in their auto over the years. The day they get back into a manual and go to stop in an emergency situation... they may end up dead cos they used the clutch to try and stop.

May not happen but you can't predict the future.

Try and stay in good habits. I recently realised that these days, I'm not coming to a complete stop at a stop sign. Now I make a concerted effort to get back into the habit. Don't fancy a fine

Left foot braking wether in manual or auto is a very very good habbit. If your not downshifting in a manual left foot braking makes sence. I don't do it out of slackness i do it out of safety.

[YOOT]

Since when did everyone become convinced that GPS is accurate for telling speed? The civilan code, or P-Code is all that navigation equipent uses and it is only accurate to about +/-10m or worse (rarely better). Good enough to work out what side of the road your on and thats about it.

The Y-code is the military code which is accurate to about 100mm or so, and for surveying use the specialised equipent can work out the integer amibiguity between the phase difference of the P and Y code and resolve your position to sub 5mm for real time. In 15min can resolve your position to sub 3mm accuracy and over 24 hours 0.1mm as long as there are more than 3-4 satellites in view (these days you usually get around 8-12).

SA or selective availabilty was disabled in 2000 as someone linked previously. The best way to measure the accuracy of your speedo is to simply time how long it takes you to travel between the 5km speedo check signs and compare the results your your speedometer. You'll be very suprised! GPS based speed is merely a gimmick. :MrT_anim:

[VilkasBAMIIXR6T]

Originally Posted by CarBroker

The cops recalibrate their equipment regularly. They have paperwork showing when the last calibration was done. If calibration is not done for a long time, it goes out of whack. From memory, that's what happened to the speed cameras on the Western Ring Road in Melbourne (and ended up costing the VIC gov't about $19M in refunds).
It is easier for the manufacturers to overestimate the speedo speed. Except on cop cars, where the speedos are calibratable (if that's a word). I used to work at Ford (for a while on the instrument panel assembly) and I remember we used special "police clusters" for cop cars.

Not sure who calibrates speedos on Victorian police vehicles but in the fords there is a digital speed read out where tripmeter etc is. This is what is used to measure speed. The Holdens already have digital speedometer. In relation to tolerance of speed that depends on member, except for the darn cameras. But then they are not police anyhow.

[VilkasBAMIIXR6T]

Originally Posted by Walkinshaw

Left foot braking wether in manual or auto is a very very good habbit. If your not downshifting in a manual left foot braking makes sence. I don't do it out of slackness i do it out of safety.

Sounds like a particular V8 supercar driver who I loathe.

[bindi]

Originally Posted by Walkinshaw

Left foot braking wether in manual or auto is a very very good habbit. If your not downshifting in a manual left foot braking makes sence. I don't do it out of slackness i do it out of safety.

Whatever. All I know is I'm sick of voicing an opinion only to have it shot down like I'm personally attacking someone.

It was just something my father taught me and I thought it was a smart thing to remember, so I figured I'd pass it on. Obviously I am wrong, because you know better.

[RED_EL_XR8]

Originally Posted by bindi

Whatever. All I know is I'm sick of voicing an opinion only to have it shot down like I'm personally attacking someone.

It was just something my father taught me and I thought it was a smart thing to remember, so I figured I'd pass it on. Obviously I am wrong, because you know better.

Actually you are both right, just like hand positions on the wheel there are differing schools of thought.

For the most case what your father taught you is probably the safest most correct option. Many driving instructors will jokingly suggest sitting on your left foot in an automatic. However for the enthusiast who wants to learn and hone a technique of left foot braking, they attain definite advantages even in daily driving.

Attempting to emulate supercar driving styles in a passenger saloon with a standard pedal box is a good way of ensuring your receive the 2006 calendar from your local panel shop.

There you go, everyone got to have a valid opinion and no one lost an eye. :

[MightyXR6Turbo]

Left foot braking belongs in Go-Karts. No point at all in a standard Saloon car as has been suggested, you shouldn't need to have your foot both on the throttle AND on the break in day to day driving. Besides, if your left foot is used for braking, which foot do you use on the clutch? ;)

[Walkinshaw]

Originally Posted by RED_EL_XR8

There you go, everyone got to have a valid opinion and no one lost an eye. :

yet...... mwhhahahahhaha

[vztrt]

Originally Posted by VilkasBAMIIXR6T

Not sure who calibrates speedos on Victorian police vehicles but in the fords there is a digital speed read out where tripmeter etc is. This is what is used to measure speed. The Holdens already have digital speedometer. In relation to tolerance of speed that depends on member, except for the darn cameras. But then they are not police anyhow.

I wouldn't worry about digital read outs, Accuracy depends on how good the ADC is. But it helps for a quick view. Analog is much more accurate.

But which model/s has the digital speed out?

[Sourbastard]

Originally Posted by vztrt

I wouldn't worry about digital read outs, Accuracy depends on how good the ADC is. But it helps for a quick view. Analog is much more accurate.

But which model/s has the digital speed out?

In the VT Commodore we used to have, there was an Easter Egg that you could activate that would do a digital display of speed next to the odometer on the dash.

I dont know if anything similar is around for fords.