Grocery Store etiquette - Check out line

Here at the main grocery store we shop at there are usually a good amount of people in the store and it seems as if everyone decides to check-out together. This can cause very long lines when there are only one or two registers open (as their typically are in the grocery store). When the line/s get too long the cashier will ring a bell and that means that another cashier will come and open up another lane. When the cashier comes they say what lane they will be opening up, so they would say lane 2, lane 3 or whatever lane they say. Back home when another lane would open up, common courtesy is used to decides who goes first. If you have been waiting in line longer someone would let you go first.
Here? nope.
Its like it is an olympic race and everybody springs to action when the new lane is called. If you can get there first you get to go first. Run someone over? Doesnt matter. 80 year-old lady? Doesn't matter. If you get there first you get to checkout first.
Okay maybe its not quite like that.....wait, pretty much. Some guy did run his cart into me the other day.
Most of the time we just stand in line and laugh as it is pretty funny to see and watch people charge for the chance to be first. It doesn't happen every time but when it does you can't help but chuckle.