General driving discussion

[TomVexille]

Re: The totally off-topic thread

Not quite accurate any more.

Australian Speedo accuracy standards

Australian Design Rule 18 sets out the accuracy standards for vehicle speedos.

Until July 2006 this rule specified an accuracy of +/- 10 percent of the vehicle’s true speed when the vehicle was travelling above 40km/h.
That is, at a true vehicle speed of 100km/h the speedo could indicate between 90km/h and 110km/h.

An odometer accuracy of +/- 4 percent was also a requirement.

As my vehicle was built before that, I suppose the +/- 10% applies

 

[Quickstatus]

Re: The totally off-topic thread

GPS uses satellites for their information. A timing error of one second gives a position error go 186,000 miles. So if any particular satellite has a timing error it is excluded out of the calculations. If you are running out of satellites the system becomes unavailable rather than give inaccurate information.

Yes understand all that, but there would be an error which I can't seem to find anywhere. I guess the error can be variable and may depend on weather, clear line of sight to satellite, doppler shift .- not sure if this is corrected for in consumer gps. Also GPs are positional speedometers (measures average speed) and not the instant speedometer found in vehicles. So the basis of measurement is slightly different. This may be important in that Radar speed detectors are instant speed detectors

 

[Quickstatus]

Re: The totally off-topic thread

107kmph in my Hilux is 100kmph true
110kmph in my Hiace is 100kmph true

Do you take yours to a testing facility

 

[Pushka]

Car thread maybe?

 

[Cossie]

Re: The totally off-topic thread

Car thread maybe?

Don't start!!!!!!

Actually I could put this one and it's associated posts here as well. http://www.australianfrequentflyer.com.au/community/playground/tv-series-discussion-ware-spoiler-67307-76.html#post1597959



P.S., good win by S.A. today against Qld, even if they were behind on the first innings, Darren's son might be the real deal.

 

[TheRealTMA]

Re: The totally off-topic thread

How do you knowc the gps is accurate?

By the science and mathematics of the method. QED.

 

[TheRealTMA]

Re: The totally off-topic thread

The Koleos I had from Hertz the other day has inbuilt GPS. It beeped a few times. Thought I was doing something wrong then realised it was a warning that we were approaching speed/red light cameras.

Very interesting.

A good Sat Nav will automatically do that. Ours has different warnings for different hazards of speed cameras, red light cameras etc, adjustable over speed warnings in built up areas and highway.

 

[anat0l]

Re: The totally off-topic thread

By the science and mathematics of the method. QED.

GPS must have come leaps and bounds. Some of the first GPS units that came out, as I recall, were horribly inaccurate, which I believe gave them a mostly bad reputation until their ubiquitous inclusion in almost every consumer device under the sun.

 

[deejo77]

Re: The totally off-topic thread

A good Sat Nav will automatically do that. Ours has different warnings for different hazards of speed cameras, red light cameras etc, adjustable over speed warnings in built up areas and highway.

The Waze app does this also......and non-fixed cameras if a user has reported it....accidents/road works/breakdowns ect

 

[TheRealTMA]

Re: The totally off-topic thread

GPS must have come leaps and bounds. Some of the first GPS units that came out, as I recall, were horribly inaccurate, which I believe gave them a mostly bad reputation until their ubiquitous inclusion in almost every consumer device under the sun.

Yes originally not precision for accurate position but for speed calculations, much better with a moving target.

 

[drron]

Re: The totally off-topic thread

Having once had a car that had a speedo 7kph under true speed and being pinged a few times until the penny dropped I always have the speedo checked before delivery.My current Hyundai has been the most accurate reading 2.5kph over.

 

[mushez]

Re: The totally off-topic thread

Looked to be doing it for both. Drove from Milton to North Lakes and back on the A3.

Should have popped in to my North Lakes office while seeing how fast that bad boy went in 2nd gear.

Hear reverse is faster than 2nd.

 

[mushez]

Re: The totally off-topic thread

Do you take yours to a testing facility

Nope - drove it with a GPS for a month plus. GPS is long bust - kids and thin wires to power - but know well what the GPS said vrs spedo.

 

[wandering_fred]

Re: The totally off-topic thread

Beware of the routings your GPS mapper might be provide, especially when there are a lot of "back roads" that are shorter than the highways (but would take twice as long).

Consider Queenstown to Dunedin on the south island.... :shock:

Happy wandering

Fred

 

[blackcat20]

Re: The totally off-topic thread

Beware of the routings your GPS mapper might be provide, especially when there are a lot of "back roads" that are shorter than the highways (but would take twice as long).

Consider Queenstown to Dunedin on the south island.... :shock:

Happy wandering

Fred

Ah yes. My friend insisted on the route that looked shorter on the map rather than the one the big street sign pointed too. Tertiary road over a mountain in the middle of winter, ice on the roads, ended up losing control of the car and sinking it into a huge bank of snow. Corollas are not made for snow/ice driving. She learned a lesson to look at the type of road and the terrain on the map after that.

 

[Quickstatus]

Re: The totally off-topic thread

Certain small roads are shorter in GPS maps because they are just lines drawn between waypoints not the actual road

 

[Denali]

Re: The totally off-topic thread

A GPS tried to tell me to drive my rental corolla up the Queenstown mountain to have dinner at that restaurant at the top of the gondola thingy.

 

[Denali]

Re: The totally off-topic thread

We also had to buy a new GPS at Christmas when we tried to get out of Perth airport and it thought we were driving around paddocks. It was very old and didnt have map upgrades. New one does.

 

[Quickstatus]

Re: The totally off-topic thread

Car thread.

thats off topic to suggest an on topic thread in an off topic thread

 

[docjames]

Re: The totally off-topic thread

Not quite accurate any more.

Australian Speedo accuracy standards

Australian Design Rule 18 sets out the accuracy standards for vehicle speedos.

Until July 2006 this rule specified an accuracy of +/- 10 percent of the vehicle’s true speed when the vehicle was travelling above 40km/h.
That is, at a true vehicle speed of 100km/h the speedo could indicate between 90km/h and 110km/h.

An odometer accuracy of +/- 4 percent was also a requirement.

From July 1 2006 a new standard began its phase in and by 1 July 2007 all new vehicles had to comply. The new standard requires that:

• The speedo must not indicate a speed less than the vehicle’s true speed or a speed greater than the vehicle’s true speed by an amount more than 10 percent plus 4 km/h.
• Odometer accuracy is no longer defined.

What this means:

• For a vehicle travelling at a true speed of 100km/h, the speedo must read between 100km/h and 114km/h. The effect of this is that many drivers will find that at 100km/h they are driving up to 14km/h below the speed limit if they rely on the vehicle’s speedo.
• The speedo must always read 'safe', meaning the vehicle must not travel faster than the speed indicated by the speedo.

This change was made to align Australian vehicle rules with those already in place in Europe. It applies to all Australian motor vehicles except mopeds.

Dealers will generally not attempt to correct speedo error unless it exceeds the legal requirements.

Which of course applies to new cars as they are sold, however tyre wear / replacement will impact this.