The fundamental concept of level of service

“What’s traffic like today?” This is a question we have all asked on numerous occasions when we prepare to make a trip as a driver or passenger in a car. What do we really mean, however, when we ask it, and what do we really expect in response? Are we interested in how fast traffic is moving? Are we interested in how congested our intended route is? Are we interested in how long we will have to wait at critical locations, like signalized intersections? Are we interested in how safe our trip will be? Are we interested in how comfortable our trip will be? The answer is, of course, “yes” to all of these. However, in answering all of these questions (assuming we can for any given case), we are creating a multidimensional matrix of possible conditions.