Â© PMA of Georgia 2010. Venting. This concept of the plumbing system breathing (while. conceptually accurate) is somewhat confusing to a. craftsperson when trying to understand specifically what. the purpose of the vent system is.
Definition of traffic jam. : a situation in which a long line of vehicles on a road have stopped moving or are moving very slowly stuck in a traffic jam.
A traffic light is a device that is designed to control the flow of traffic by using three colored lights. These lights are mainly green, yellow, and red. In 1860s London, the first traffic control device had arms that extended out to command drivers on how to react at an intersection.he best historical example of traffic control that relates towards a traffic light is the use of traffic cops to control the flow of traffic on London Bridge in 1722. Three men were given the task of directing traffic coming in and out of either London or Southwark.