It's easy to blame people. Thing is, it's a natural state of traffic flow for jams to occur - it doesn't necessarily fall to human error or impatience. You can have gridlock with as few as four cars, in low traffic volume, with each car following correct road procedures: Please Register or Log in to view the hidden image! Each of these cars is proceeding as considerately as reasonable. Each leading driver stops to make their left turn, and each trailing car stops behind. Notice that the road ahead is clear - it is low traffic volume. The drivers are on a clear road, and thus the trailing drivers have no reason to expect they are about block a side street (like they might expect in high volume, slow traffic). This can happen before anyone has time to realize it will result in gridlock. Sure, it's a simple example, and relatively easily to sort out with time, gear-shifting and space (as long as there's enough of all three), but the principle remains - it is not necessarily about people being rude, impatient or neglectful.