Speedo v Waze

[gaznp]

I was driving up the Bruce Highway this morning out of Brisbane, i looked at the speedo, i was doing 106 kph,i looked over at Waze on the map navigation screen it registered 116 kph, which one is correct, surely the speedo isn't out by 10 kph.
I have standard wheels and tyres on my 2018 gt auto.

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[JohnDoe]

Try another app and find out

 

[GW65]

Unless you've changed the rear tyre size I'd expect the speedo to over-read - certainly with cars sold in Europe they're not allowed to under-read so manufacturers build in a fudge-factor to allow for tread-depth, snow-chains, etc. Comparing mine against the GPS speed reading on my dash-cam, the speedo over-reads by about 5% (so 40mph on the speedo equates to 38mph on the dash-cam).

 

[scollist]

Try Speed Box app on iPhone to benchmark your speedo against GPS speed. Try and do it at a constant speed on the freeway (100kph is good) when the skies are clear to ensure you get maximum satellite pickup for the GPS.

Your speedo should read (correction) more than the GPS speed. If not it is illegal and probably should take back to the dealer.

 

[Hornet]

Try Speed Box app on iPhone to benchmark your speedo against GPS speed. Try and do it at a constant speed on the freeway (100kph is good) when the skies are clear to ensure you get maximum satellite pickup for the GPS.

Your speedo should read less than the GPS speed. If not it is illegal and probably should take back to the dealer.

You mean Speedo should read more than GPS

 

[GW65]

You mean Speedo should read more than GPS

+1

Australian rules were changed back in 2007 to align with European rules - speedo can never under-read, and most it can over-read is +10%+4km/h. So at a real 100 km/h, the speedo can legally be anywhere between 100-114 km/h.

 

[Stonehenge360]

I think Waze did bad update. The past month my Waze says I am always doing 10mph over what I am. Interesting that it adds both 10mph and kmh...sounds like faulty math in their code

 

[Aubrey]

Waze problem, I was on 100 and it was showing 116. My 100 was backed up by my nguage speed. Noticed a bit later that Waze was same as my nguage, so it’s inconsistent.

 

[Stonehenge360]

Waze problem, I was on 100 and it was showing 116. My 100 was backed up by my nguage speed. Noticed a bit later that Waze was same as my nguage, so it’s inconsistent.

Strange thing is that it’s non linear. For me, 0mph is the same on both, 20mph gives a 5 or so difference, and 70mph gives a 10 or so difference. If it was a simple math error in the code, Waze should read -10 or something at idle. I may drop them a bug notification

 

[scollist]

You mean Speedo should read more than GPS

Correct (what I meant - should check my logic before hitting the post button)

 

[steerage250]

Strange thing is that it’s non linear. For me, 0mph is the same on both, 20mph gives a 5 or so difference, and 70mph gives a 10 or so difference. If it was a simple math error in the code, Waze should read -10 or something at idle. I may drop them a bug notification

No, it won't be a simple arithemetic offset (ie it won't be the same absolute error at all speeds) - it will be a percentage error (hence both will read zero together, but the absolute error will get bigger and bigger the faster you drive)

 

[Walt Kowalski]

I think Waze did bad update. The past month my Waze says I am always doing 10mph over what I am. Interesting that it adds both 10mph and kmh...sounds like faulty math in their code

Yes. Mine has suddenly reading crazy. Bruce Highway N of Brisbane too

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