Empirical features of congested patterns at highway bottlenecks.

An empirical study was undertaken of congested patterns at highway bottlenecks. On the basis of statistical data it was found that the spatial-temporal structure of congested patterns possesses some predictable features. From these features a classification of congested patterns was made. It was found that the most frequently observed congested pattern is the general pattern (GP). In GP synchronized flow occurs upstream of a bottleneck and wide moving jams spontaneously emerge in that synchronized flow. Capacity in free flow can be about twice as high as capacity in congested traffic upstream of the on-ramp if the GP has formed.