Publication: Evaluation of ramp metering using a microsimulation model for mohammed al-qasim expressway
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Date
2024-09-01
Authors
Al-Zairji Wafaa, Khudhair Luaibi
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Abstract
Traffic congestion in highways posses a real issue that has been considered as
a challenging issue for many researchers and authorities, especially in the merging
section. Many studies and applications focus on addressing congestion in the merging
section. The ramp metering (traffic management) has the highest priority for solving
this issue by managing traffic lights in the ramp. The ramp metering technique uses
managing algorithms for traffic management control. Simulation softwares, like
AIMSUN, VISSIM, PARAMICS, are utilized for design and implementation of
microsimulations that reflect highways ramp metering behaviour. This thesis focuses
on addressing the issue of traffic congestion in the Mohammad Al-Qasim expressway,
located in the capital of Iraq, Baghdad. The Mohammad Al-Qasim expressway
features six entrances and exits that span from the northern part of Baghdad to the
southern part of Baghdad. Data has been collected for this expressway using fixed
video cameras along the route. The AIMSUN simulation software has been verified
and validated using the collected data. Geoffrey E. Havers (GEH) analysis was
conducted to compare the actual and simulated data. Thus, the simulated data can be
relied upon for applying the ramp-metering method. The AIMSUN software has been
used to investigate the ramp metering (RM) method for two different strategies. The
first type is local ramp metering, while the second is a coordinated ramp metering
system. The ALINEA algorithm was used to simulate and apply ramp-metering for
both the local RM model and the coordinated RM system. For local RM, the ALINEA is determined by the critical occupancy in the downstream. In the coordinated RM
system, the ALINEA algorithm is dependent on the critical occupancy of both the
upstream and downstream. The simulated results indicate significant improvements in
flow, speed, and occupancy. The flow and occupancy for local RM models have
improved from 2.93-6.20 percent in terms of vehicle flow. The improvement in vehicle
flow ranges from 4.88 to 34.38 percent for the coordinated RM system. These results
demonstrate that the effect of ramp metering has a significant impact on the coordinate
RM system. This leads to an increase in expressway capacity. These findings represent
a novel study of ramp-metering applied to the Mohammad Al-Qasim expressway in
Baghdad, Iraq. These findings are reliable for reasearchers that interested in ramp
metering and also institutes of highways for ramp metering realization.