Was following a friend's car and I realize she was always travelling 10+ below the speed limit...
When we stopped, I asked her why. she said she was going 90+ Kmph all the way.
Then I took a car for a spin and check the speedometer against my phone app.
To hit 90km/hr, she have to go 102-105km/hr.....
My friend say she did not know her speedometer was off and always thought that those who overtook her from the left are speeding.....
Now I finally know why got so many people going 70-80km/hr on the rightmost lane of the expressway....
That is because their speedometer reading is off after they changed their rims/tyres.
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