IntroThe two kinds of traffic jamsA famous example of the traditional type of jam: end of Chinese week-long national holiday, drone footage by Sohu TV Bruce Greenshields the pioneer: flow = density * velocityPhD work in 30s Discovered two linear regimes for traffic From symposium publication "75 years of the fundamental diagram for traffic flow theory" Lighthill & Whitham's two-part paper of 1955The first paper was on "flood movement in long rivers" The second paper was a landmark paper, giving rise to the macroscopic flow density and shock formation from physical theories like those of compressible gases, instead of just tracking each vehicle individually. See here for an introduction to and review of the continuum traffic flow models The all-important q-k curve(On chalkboard) MIT Mathematics: Traffic ModelingResearch group homepage (and there are many more research groups working on mathematics & modeling of traffic flow) Jamitons and Jamitinos: a hybrid traffic jam example Comments on the inviscid model - No dissipation of shock unless conditions change dramatically enough - Some viscosity (i.e. preventative, overly-careful drivers) can also help The end of phantom traffic jams?Take-home message from TrafficWaves.org's Bill Beaty |