Traffic was studied on a thirty kilometer section of freeway north of Frankfurt Am Main, Germany using archived loop detector data. The spatial-temporal characteristics of over eighty bottleneck activations were diagnosed with six days of data. The analysis tools used were curves of cumulative vehicle count and time mean speed versus time. These curves were constructed using data from neighboring freeway loop detectors and were transformed in order to provide the measurement resolution necessary to observe the transitions between freely-flowing and queued conditions and to identify important traffic features. The bottlenecks' locations, pre-queue flows, and mean discharge flows across all lanes and on a lane by lane basis were found to be reproducible from day to day. Further, it is shown that the bottlenecks' mean discharge flow was about 3-5% lower than the mean prevailing flow prior to queue formation when freely flow conditions preceded the activation. Changes in key traffic parameters leading to the formation and dissolution of diverge and merge bottlenecks were investigated and were found to reproducible from day to day. The bottleneck formation triggers for diverge bottleneck activations preceded by freely flowing traffic included high flows across all lanes and high, truck dominated, flows in the right lane just upstream of the bottleneck location. For merge bottleneck

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