It’s Time for Some Queueing Theory
It can apply to familiar lines like those at the grocery store or bank but also to things like web servers, highway traffic, and telecommunications…basically any situation where you have things entering a system, being processed by a system for a certain period of time, and leaving the system. Because people stand in the same line, waiting for a register to become available, there are no “slow” lines, delayed by a coupon-counting customer or languid cashier. See also How to Pick the Fastest Line at the Supermarket, Queue Theory and Design from 99% Invisible, and this paper from Bob Wescott, Seven Insights Into Queueing Theory.
Source: kottke.org