Development of Maximum Weaving Length Model Based on HCM 2016

Abstract

Weaving segments are among the most important segments in any kind of facility. One of their key features is their maximum length (Lwmax), which determines the performance of the facility as a weaving or separate merge and diverge segments. Based on an equation in the Highway Capacity Manual (HCM 2016), only two variables VR (volume ratio) and Nwl (number of weaving lanes) influence this length. However, certain cases can be found in which traffic conditions are different but Nwl and VR values are equal. In this study, three separate weaving segments in Tehran, Iran were used and their data were collected to further analyze the influence of the traffic parameters. Calibration of field data was performed using GEH values of freeways and ramps for simulation and field traffic volumes. The simulation was therefore used on the basis of different traffic and geometric parameters, and the effects of these parameters on Lwmax were carefully observed. There were 184 simulated scenarios in Aimsun using data collected from the three weaving segments in Tehran plus simulation. In these scenarios, two geometric parameters (Nwl and Lwmax) and four traffic parameters were considered variable. It was found that for Nwl = 2 the accepted regression model containing three new variables has an R2 value equal to 0.95, and for Nwl = 3 two of the three variables were used for the model produced with an R2 value equal to 0.7.

Studying the Level of Service of Two Sided Weaving Section on Urban Roads

“…In this study, four traffic parameters and two geometric parameters (Nwl and Lwmax) were considered variables. It was noted for Nwl = 2 the accepted regression model containing three new variables has an R2 value equal to 0.95, and for Nwl = 3 two of the three variables were used for the model produced with an R2 value equal to 0.7 [6].…”