60 Mph/97 Kph

[leocylau]

how long will it take to fix this minor bug

[AlanOfTheBerg]

I wouldn't hold my breath, if I were you, and I wished to remain on the earth a while longer. Give it 2-3 releases.

[llayden]

I love the thoroughness of your research. Low three figures is interesting - but how low did you go?

Was 6 a problem?

Ireland moved from miles to kilometers sometime in the last ten years. (One solution would be to join us - the speed limits go up 60->100kmph (62.5)) My current car reads in km, my previous one (same make and model) read in miles. The cruise control on my previous car easily came to rest at 60 and a click up or down added or subtracted 1MPH. My current one will not set at 100 - 99 or 101 and 1 click up or down still adds/subtracts 1MPH - however in both cars my sat nav (& now Waze) tells me I'm going faster.

I am a mathematician by training but cannot think of any reason to explain your problem (mine perhaps). I have seen situations with digital to analog converters (or vice versa) where because of the change of base, some numbers are missed out or doubled up but in this case the calculation is a distance divided by a time and I assume no integer arithmetic is being done.

Here's an experiment for you and your quiet motorway: Create a road segment in Waze that is exactly one mile long. Don't let any other wazer drive it. Mark the start and finish with posts. Drive the section as often as you can at 60MPH - timing each run as well, to check your speedometer (this is why you need the posts). (Alternatively borrow a speed cop's camera gun). Now wait for Waze to upload your routes and check the average speed recorded for the section. Don't get arrested doing any of the above impossible things.

This won't solve your problem but it may provide you with more fun.

[harling]

I love the thoroughness of your research. Low three figures is interesting - but how low did you go? Was 6 a problem?

I am a mathematician by training but cannot think of any reason to explain your problem... in this case the calculation is a distance divided by a time and I assume no integer arithmetic is being done.

As it turns out, a combination of integer arithmetic and the use of an intermediate unit that is coarser than the final unit is precisely why this happens, as I explained back in February in this thread:

On the client, current speed is stored internally as an integer, in terms of knots. When displaying the speed, this is converted to mph/kph by multiplying by 1.151 (mph) or 1.852 (kph), and then truncated to just the whole-number part. Because the Knot is larger than either unit, and it has already been rounded to the nearest whole number before being converted, it is inevitable that certain speeds in each system will never be displayed on the client:

mph: 7, 15, 22, 30, 38, 45, 53, 60, 68, 76, 83, 91, 99, 106, 114, 121, 129, 137, 144
kph: 2, 4, 6, 8, 10, 12, 13, 15, 17, 19, 21, 23, 26, 27, 28, 30, 32, 34, 36, ...

[ircphoenix]

Are you kidding me? A 5 page post about Waze displaying +/- 1mph instead of the actual speed? THIS is the issue that people are getting fussy about? Jesuchristo...

[harling]

Are you kidding me? A 5 page post about Waze displaying +/- 1mph instead of the actual speed? THIS is the issue that people are getting fussy about?...

It isn't about inaccuracy; it's about the curious fact that the client absolutely will not display certain speeds (e.g., 60mph) no matter what, and why that is.

If 60mph had not been one of those speeds, chances are nobody would have noticed.

[Laakkus]

Are you kidding me? A 5 page post about Waze displaying +/- 1mph instead of the actual speed? THIS is the issue that people are getting fussy about? Jesuchristo...

Second

Sent from this Galaxy

[dmcconachie]

Are you kidding me? A 5 page post about Waze displaying +/- 1mph instead of the actual speed? THIS is the issue that people are getting fussy about? Jesuchristo...

To be fair it started off, and the majority of the thread is, a matter of intrigue rather than people having a moan. Not sure why it became a bug that simply has to be solved.

[gettingthere]

I don't know about other countries but I believe that in the US car speedometers only needs to be accurate to +/- 6 mph. So really no big deal if Waze won't display 60 mph. It's close enough and measuring your speed is not the primary function of a commuting GPS application.

Let's get Waze focusing on more important things such as ramp names that don't display, finishing the new map editor, improving the editing of the IGN editors, stabilizing the server infrastructure AND very, very, very important - fixing the calculation of the top weekly Wazers!

[dmcconachie]

I don't know about other countries but I believe that in the US car speedometers only needs to be accurate to +/- 6 mph. So really no big deal if Waze won't display 60 mph. It's close enough and measuring your speed is not the primary function of a commuting GPS application.

Let's get Waze focusing on more important things such as ramp names that don't display, finishing the new map editor, improving the editing of the IGN editors, stabilizing the server infrastructure AND very, very, very important - fixing the calculation of the top weekly Wazers!

You'll probably find it's +6 rather than -6, pretty sure it's illegal here for a speedo to report less than the actual speed.

Definitely agree with your other points though! My kingdom for a stable waze!