speed limit

Hi, are there any apps for iPhone that detect the speed limit based on your real time location and that if you go over it they sound an alarm? Preferably a tone that keeps playing until you go back to below the speed limit? I assume if there are any apps they would work in most countries, but...

I'm looking for a way to reduce the speed of other users on my Huawei E5785lh 4g mifi . There is a guy who is always on YouTube watching videos which slows mine when I'm about to watch live footbal. The truth is he does not read online nor do or her things than than watching videos on YouTube...