Why in the USA at the entrance to the store establish a line of

Many of those who managed to visit the United States was surprised to notice at the entrance to the U.S. stores are on the vertical ruler. It can be attached to the left of the entrance, or even in the middle of the sliding doors.

Hypotheses about why this thing, there are many, but the correct answer in addition to American trade, few know.

Variants of using the range you can hear a lot. Someone will assure you that it is designed for tall people so they don't hit your head, someone to tell me what the line helps to estimate the dimensions of major products, which are carried out of doors. There are more strange explanations that gives rise to boundless human imagination.

In fact, the scale-length near the door shopping is one way of fighting crime, introduced in the 70-ies of the last century. The robbers of the stores at that time not too stand on ceremony with those who try to object to them and immediately used the weapon.

Therefore, the authorities have taught citizens to be, first and foremost, good witnesses, not heroes. Sellers and visitors of a supermarket, a jewelry shop or café strongly advised not to resist robbers, and carefully to observe them.

"Treat them like your best customer: give them what they want and get them out the door", said a basic rule of behavior in case of a robbery. The line at the entrance allows you to accurately fix an important sign of the attacker, which is impossible to change his height.

People under stress tend to exaggerate the height of the robber. That's why the police often searched for six-foot bruiser, instead of the puny and stunted thugs.

The line effectively solves this problem by eliminating the human factor. Even if all participants in a robbery in panic I forget to look at the ruler, the rise of the raiders will lock the surveillance camera aimed at the entrance.

About rulers know not only of trade, but criminals. Statistics says that in shops where there is such a device, much less attack. Therefore only recommended police innovation began to be in demand.

The first trade network to introduce mandatory ruler to measure growth in all of its supermarkets, has become a 7-Eleven.

For 10 years, from 1976 to 1986 the number of night attacks on shops around the clock network has decreased by 50 percent. Based on this experience, the national Association of convenience stores advise everyone to use a line and they appeared in thousands of markets throughout the United States.