Effect Of Ramp Combination Type And Distance To Average Speed Of Combination Area In Urban Freeway

In urban freeway, diversion and merging between two closely spacedramps are disturbed by each other, which should be considered as acombination. Combination area formed by ramp combination is mostinfluenced and becomes the bottleneck of freeway. Research on averagespeed in combination area is of great importance for improving trafficefficiency of freeway, which is significantly influenced by combinationtype and distance.This thesis made research on the effect of ramp combination type anddistance to average speed in combination area from qualitative andquantitative aspects. Relationship between average speed of combinationarea and ramp distance is studied based on validated micro-simulationsoftware TSIS. Results indicate that for different ramp types, averagespeed of combination area is greatly impacted by ramp distance, risingwith the increase of ramp distance and finally trending towards stability.The thesis analyzed factors influencing average speed in combinationarea and developed statistical models for four different ramp combinationtypes. Besides the thesis explored ways to improve average speed incombination area based on established quantitative models and pointed outthat increasing ramp distance reasonably is an effective measure. Themodified models are used to provide advice on ramp combination typechoice and reasonable distance intervals for certain freeway volume andaverage speed in combination area are proposed for practical use.