To avoid speeding fines, all modern speedos show more speed than what you're travelling on. Surprising people don't know that already. I've personally checked on multiple modern and older cars, using GPS and draggy. Only on older cars is the speedo sort of accurate, like +5 kmphs over reporting.
"The regulation states that speedometers must never underreport a vehicle's speed, while it must never overreport by more than 110% of the actual speed + 6.25mph. So if you're going 40mph, your speedometer may read up to 50.25mph - but it can never read less than 40mph"
