Aspects of Temporary Hard Shoulder Running on Freeways

Problem Statement

On federal freeways, the temporary hard shoulder use during heavy traffic creates additional capacity through an additional lane. This improves the traffic flow, thus avoiding traffic congestion and reducing the risk of accidents. Furthermore, travel time and fuel consumption are reduced. In the event of temporary capacity bottlenecks, investment costs can be kept low compared to an infrastructure expansion. In order to achieve an overall benefit, the risks due to additional lane changes and due to the absence of the hard shoulder for defective vehicles and operational service, are to be minimized. When implementing a temporary hard shoulder running, it must be ensured that the risks are reduced to a minimum. This can be achieved by appropriate technical equipment, e.g. dynamic freeway control systems.


The main objective of this project is to process existing findings and to combine them with current data in order to derive future requirements for temporary hard shoulder runnings.


All German freeway sections with temporary hard shoulder runnings are recorded and analyzed with their constructional, operational, traffic and traffic law characteristics. A cost-benefit analysis of all aspects will enable a more targeted use of funds. The inclusion of traffic safety is of particular importance. In addition, the effects of temporary hard shoulder runnings on traffic are examined using microscopic traffic flow simulations. Based on the simulation results, a recommendation can be made as to which entry and exit types can be used economically in which traffic load scenarios.

The Institute for Transport Studies is in charge of the microscopic traffic flow simulations.