THE IMPORTANCE OF LANE-CHANGING ON MOTORWAYS

Details are given of a study over a one-kilometer section of German autobahn equipped with detectors at 100 M intervals. The results are based on microscopic data for 2000 lane-changes and macroscopic values for 11000 lane-changes. The number of passings was also determined from the output of the event-recorder. The results are used to establish the relationship between frequencies of passing and of lane changing as a function of traffic volume. Regression analysis is used to show a close relationship between the two quantities. A model was developed to estimate the effect of lane-changing on traffic safety. It is shown that 10 to 15 obstructing lane-changes per kilometer per hour could be expected at volumes exceeding 2000 veh/h. A method is suggested for using the model to consider traffic volume conflicts when evaluating the accident rate for a road section. It is also suggested that "no lane changing" signs could be used when dense traffic is created at a bottleneck. (TRRL)