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In the Highway Capacity Manual there are two factors accounting for the platooning in vehicle arrivals and filtering effect caused by the upstream signals, namely the progression adjustment factor and the upstream filtering adjustment factor. The progression adjustment factor is only descripted by the arrival types. In a planning scenario, the plan...
Citations
... Thus, this mathematical formula eliminates the need for using default values. Again, another approach was taken by (Wu, 2014) to modify the Progression Adjustment Factor (P.F.) considering the planning aspects. (Wu, 2014) provided valuable insights into P.F. ...
... Again, another approach was taken by (Wu, 2014) to modify the Progression Adjustment Factor (P.F.) considering the planning aspects. (Wu, 2014) provided valuable insights into P.F. formulation for default conditions. ...
A mathematical expression of supplemental adjustment factor (fPA) has provided a way to estimate Progression Adjustment Factor (P.F.) more accurately as the P.F. relies on the fPA value. The mathematical formula of fPA requires traffic parameters that need to be determined from the field survey. As non-lane based traffic behavior is significantly different from lane-based traffic, this study examines the applicability of the default fPA values of Highway Capacity Manual-2000 under the non-lane based traffic condition. Default values for all six Arrival Types (AT1 to AT6) are reviewed against an available mathematical expression. After performing statistical analysis on the collected data, it is found that the HCM-provided default fPA values for AT1, AT3, AT5 and AT6 are consistent with the mathematical expression. However, the supplemental factors for AT2 and AT4 are found to vary significantly from the default values. By considering the mathematical expression as a standard of comparison, a graphical representation of error corresponding to trial fPA value shows that a value of 0.99 for fPA provides the minimum error of P.F. for AT2. Thus, the default value (fPA =0.93) is found to underestimate fPA as well as P.F. by 6.5%. In a similar way, the fPA value for AT4 is found to be 0.96 which is 16.5% less than the default value. So, the default value (fPA =1.15) overestimates fPA and P.F. by 16.5%. Therefore, fPA = 0.99 for AT2 and fPA = 0.96 for AT4 should be used to estimate P.F. in case of non-lane based traffic.
... The average delay for automobile is calculated according to a model developed in Germany (Brilon and Wu, 1990;Wu, 1997;Wu, 2014). The model can take into account the instationarity in the peak-hour using an instationarity factor f in . ...
The first version of German Highway Capacity Manual was published in 2001. Now, a new version is published in 2015 (HBS 2015). For the new German Highway Capacity Manual, most major chapters are revised and some of them are totally rewritten. The chapter for signalized intersections is one of the most important chapters in a highway capacity manual. In the new German Highway Capacity Manual, this chapter is totally rewritten in accordance with forthcoming developments in the past 10 years. In this paper, an overview of the chapter for signalized intersections in the new German Highway Capacity Manual is presented. Procedures dealing with capacity and delay analyses are introduced. Differences between the former version and the new version of the German Highway Capacity Manual are indicated and discussed.
