Yes, the speed reading is currently unreliable at 3.2 km accuracy. As you can see in the screenshot, your GPS accuracy/cell net signal strength is very, very low at this point - about 3.2 km!!! There is a best effort calculation of speed and position - usually even if your GPS is about accurate to 1-2 km, the speed calculation is somewhat OK.
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1. upto 100m accuracy - the speed will be perfect.
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upto 500m accuracy - the speed is calculated from sensors, and should be pretty accurate.
3. upto 1.5 km - the speed is still good - should be +- 20kmph
4. at 3.2 km - you may get crazy results like the screenshot above.
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However, we are continuing to improve accuracy by collating inputs from GPS, cellnet, accelerometer & gyroscope. Improvements will be made in future versions of the app.
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Thanks for your patience.

The speed is calculated from GPS/wifi/cell tower & sensor signals. For accuracy within a 100m GPS radius with direct satellite line-of-sight, the speed is perfect. Accelerometer/gyroscope sensors are noisy and cannot be entirely relied upon. With cellnet signals upto 1.5 km radius, the speed is calculated as an average over the last 1 minute. Beyond 1.5km, and as in the case above, 3.2 km, the speed values may be unreliable, and will be disqualified/not displayed in future versions of the app.
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However, we are continuing to improve accuracy by collating inputs from...
more...

GPS, cellnet, accelerometer & gyroscope, and removing sensor noise. Improvements will be made in future versions of the app.
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Thanks.