A TRAFFIC simulation system is helping drivers by predicting jams on Germany’s autobahn network up to an hour before they happen. The secret of its success is to take into account the way real drivers – and their cars – behave.
When engineers model the way road traffic flows they break the traffic down into three categories: freely flowing, jammed, and an intermediate state called synchronised flow in which dense traffic moves in unison, like marchers moving in step.
But this synchronised flow is unstable. One car pulling into another lane and forcing the driver behind to brake hard is enough to…
