• Journal of Korean Society of Transportation
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• v.28 no.3
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• pp.29-37
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• 2010

Ramp metering control is the most representative strategy of uninterrupted flow control and management system. Ramp metering is to adjust vehicles entering an expressway in such a way that expressway mainline maintains flow stability by regulating ramp vehicles. The effect of two metering strategies, single-entry metering and platoon metering, on mainstream under the same metering rate with pre-timed metering are analyzed by micro-simulation. Platoon metering shows lower performance than single-entry metering under the same metering rate in terms of speed, density, and delay, causes earlier breakdown than single-entry metering. It indicates that the selection of metering type has critical importance as the flow of mainline is high.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.12 no.2
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• pp.1-11
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• 2013

This research proposed integrated expressway traffic management strategy using ramp metering and toll mainline metering. This research suggested a traffic signal optimization model for integrated operation of ramp and mainline metering based on Demand-Capacity Model that is used to optimize allowable input volume for ramp metering in FREQ model. The objective function of this model is sectional throughput volume maximization, and this model can calculate optimal signal timings for mainline metering and ramp metering. This study conducted an effectiveness analysis of integrated metering strategy using PARAMICS and its API. It targeted Seoul's Outer Ring Expressway between Gimpo and Siheung toll gate. As a simulation result, integrated operation of mainline and ramp metering provided more smooth traffic flow, and throughput volume of mainline increased to 14% in congested section. In addition, a queue of 400 meter was formed at metering point of toll gate. This research checked that integrated traffic management strategy facilitates more efficient traffic operation of mainline and ramp from diffused traffic congestion.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.23 no.4
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• pp.16-36
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• 2024

This study, developed a dynamic hard shoulder running(HSR) algorithm that includes ending speed and minimum operation time in addition to the starting speed for HSR, and presented an operation plan. The first stage of the algorithm was red, which means vehicles are prohibited from HSR. The second stage is red/amber, in which drivers are notified of HSR, and operators are given time to check whether there is any obstacle to HSR. Stage 3 is green, which vehicles are permitted for HSR. Stage 4 is amber, in which a signal is given to drivers that the end of HSR is imminent. In addition, a minimum time is applied to green and red, but if congestion is severe, red is terminated early to prevent congestion from worsening. The upstream and downstream traffic flow is managed stably through main line ramp metering and lane number matching. The operating standard speed reflects the characteristics of vehicles and drivers, and based on simulation results, 7090 was selected as the optimal operating standard speed considering traffic flow and safety aspects. Therefore it is desirable to apply the travel time divided by the minimum speed of the HSR link as the minimum operating time in order to ensure continuity of traffic flow