Traffic Operation and Safety of Freeway Weaving Segments in Germany

Weaving segments on freeways can be used if the distance between two adjacent interchanges is too small for implementing separate merging and diverging areas. The German Guidelines for the Design of Motorways define different types of weaving segment. In this study, the traffic operation and safety of freeway weaving segments between interchanges in Germany are analyzed. The traffic flow analysis was based on trajectory data obtained from video measurements at weaving segments with different geometric and operating conditions. For the safety analysis, crash data over a period of 5 years were evaluated. Based on the traffic flow measurements, it was found that the majority of the entering and exiting vehicles generally carry out the necessary lane change at the beginning of the weaving segment, so that a minimum segment length of 300 m is sufficient for proper operation. The crash analysis revealed crash rates of freeway weaving segments between interchanges similar to those of basic freeway segments, which contradicts previous concerns against the use of weaving lanes at main carriageways.