Interactions between basic sections and junctions in overload situations

Overloads, for instance at individual junctions or on uphill stretches, can lead to congestion in adjacent sections and junctions in the dense motorway network. The backlog caused by overloading of one element into other elements has not yet been taken into account in regulations. On behalf of the Federal Highway Research Institute (BASt), a procedure adapted to German conditions was therefore developed following the example of the FREEVAL instrument used in the USA for several years. This approach – pursued with German FREEVAL –offers great potential for further areas of application, especially in traffic planning. It closes a gap between the design methods of the HBS, which in individual cases reach their limits, and the microsimulation methods, which have to be calibrated with considerably greater effort. The program is to be made available to the road construction authorities as open source software.