Abstract
In this study, stochastic breakdown phenomena on a two-lane section of a Japanese urban expressway are analyzed and modeled. Because the bottleneck of the subject section is supposed to be a complex geometry with an on-ramp, a horizontal curve and an uphill, analysis is conducted not only by cross section but also by lane to understand the characteristics of breakdowns in detail. For such a detailed analysis, applicability and limitation of the detector data with different aggregation intervals are also considered. Through the analysis, it is found that about 40% of breakdowns in the section occur first on the shoulder lane; one of the causes would be higher merging traffic volume. The estimation of breakdown probability shows that the capacity of the median lane is about 300-veh/h greater than that of the shoulder lane. Furthermore, it is found that the discharge flow rate deteriorates as the elapsed time after breakdown increases, especially at the beginning of congestion.
