EURO 2024 Copenhagen
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828. Optimizing Urban Expressway Exit Ramp Lengths through Microscopic Traffic Flow Simulation: A Case Study Using PTV VISSIM

Invited abstract in session MC-56: Traffic flow modeling , stream Transportation.

Monday, 12:30-14:00
Room: S04 (building: 101)

Authors (first author is the speaker)

1. Yunzhu Lin
Department of Civil Engineering, Chung Yuan Christian University
2. Yu Chang
Department of Civil Engineering, Chung Yuan Christian University

Abstract

This study presents a method using microscopic traffic flow simulation to assess urban expressway exit ramp layouts, addressing the problem of ramps too close to surface road intersections, leading to insufficient queuing space. Utilizing PTV VISSIM, a real-world case is analyzed over 65 minutes, including a 5-minute warm-up phase. The core simulation spans one hour, segmented into six 10-minute intervals. The research fine-tunes the Wiedemann 74 car-following model using comparative analysis of observed and simulated traffic volumes, adjusting parameters to match site conditions. Validation criteria require a percentage difference of under 10% and a GEH statistic below 5. Building on the validated base traffic model, which uses a 90-meter ramp length, the research extends the model to simulate scenarios with ramp lengths of 150, 200, 250, and 300 meters. Through linear regression analysis of the simulation data, relationships between traffic flow and density for these configurations are established separately. These findings are then mapped against the Highway Capacity Manual’s service level density ranges to determine the optimal lengths for varying traffic flow conditions. The findings indicate a significant flow increase when extending the ramp from 150 to 200 meters, peaking at 250 meters. However, it also shows that a 200-meter ramp connection length optimizes queuing lengths, suggesting a balance between increased flow rate and minimized vehicle congestion.

Keywords

Status: accepted


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