45 mph, then 55 mph, back down to 45 mps: Have you ever wondered as you’re driving how speed limits are set?

The Michigan State Police (MSP) and the Michigan Department of Transportation (MDOT) are now releasing their procedures on how they decide when drivers can cruise along and when they have to inch their way through towns.

"We work closely with our partners in law enforcement to establish the safest speed limits possible for the benefit of all motorists," said State Transportation Director Kirk T. Steudle in a written release.

Their process on choosing a speed limit for a section takes studies, engineering, and investigations. "Our comprehensive analysis in determining speed limits relies heavily on identifying normal and safe driver behavior and whether or not a speed limit is realistic," said MSP Director Col. Kriste Kibbey Etue.

The two groups launched a new youtube video, that explains further how they choose the speed limit for an area.  You can watch the video below, and find more details on their process by clicking here.