you can adjust the limit at which point it alerts you. You can set when the alert will go off area that have below 80km/h speed and those with speed over 80km/h. Mine is set to ping on 15km/h+ on the slower areas and 18km/h+over on the higher.
You can always turn that speed warning off if it bothers you.
They could also not be a dick and stick to the speed limit.