The term "wide moving jam" is meant to reflect the characteristic feature of the jam to propagate through any other state of traffic flow and through any while maintaining the velocity of the downstream jam front. The phrase "moving jam" reflects the jam propagation as a whole localized structure on a road. To distinguish wide moving jams from other moving jams, which do not characteristically maintain the mean velocity of the downstream jam front, Kerner used the term "wide". The term "wide" reflects the fact that if a moving jam has a width (in the longitudinal road direction) considerably greater than the widths of the jam fronts, and if the vehicle speed inside the jam is zero, the jam always exhibits the characteristic feature of maintaining the velocity of the downstream jam front (see Sec. 7.6.5 of the book).