Why do semi trucks pass, each other, when driving on the freeway if they are all going the same speed?

Semi's (aka: truck trailer combinations...not semi trucks) drive at different speeds depeinding on the skill and disposition of their drivers. While the statutory limit if 55, truckers will push the limit just like other drivers. Also, people of not so much experience have an instinctive need to occupy the same place as any vehicle ahead of them. Only the rare driver drives with hs head and not his ego. And trucking is very much an ego trip, as any of the lies truckers tell about encounters with females will soon convince you.

_There is a thing called tail gating , and although it's an easy statement you'll get there when you get there , slowing down for every slower vehicle over a 2 day or 3 day trip likely will make you late for your appt. And yes we do have appt's and could be punished severely (financially) if late.

_Walmart biggest retailer in America ... has a 2 hr window of their appt times for you. Meaning it's recommended you get there an Hr before but not earlier and you can arrive up to an hr late. Now in the event you're 2 hrs late your company has to reschedule and it very well could mean you sit without pay for 2 days waiting to unload.

_People in this country are completely unaware of the inconveniences truckers are subject to , to achieve the conveniences most people take for granted.

_There are also many semi drivers that speed up to stop another truck from passing , there are those who hit the left lane to pass , and go slower passing another truck then speed up and go faster once around that one they passed , that likely is fear factor while out there in the left lane.

_I've put a turn signal on only to have 7 to 10 vehicles left lane ram themselves up the poop chute of the one in front of them to ensure Mr trucker can't get out. It's not only the semi taking it's turn at ignorance , each and every person out there wants turn.

If they pass each other, they must not be going the same speed. Some trucks weigh more, while others could be empty so therefore faster.

This is called aptly Leap Frogging. I think they do it out of enthusiasm, for much the same reasons frogs do it. Do frogs play leap frog?

If one passes the other then try aren't going to same speed

Because they are NOT all going the same speed!

there's a maximum and minimum speed limit and as we all know there are people who speed and go slower than the posted limits

they are not all going the same speed

the vast majority of those who drive tractor trailers do not obey the 55 mph speed limit, and will, illegally, pass vehicles, even sometimes driving in the # 1 lane...............many of them are, shall we say " from another country" and don't adhere to laws............too bad there are not more highway law enforcement officers to cite these idiots !!!!