• Journal of the Korean Society of Industry Convergence
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• v.4 no.1
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• pp.41-49
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• 2001

This study developed signal optimization algorithm by analyzing vehicle arrival patterns. The major principle of signal optimization is dissipate all queueing vehicle in 1cycle and assign delay time uniformly for all approaches. For this, this study used optimal green time and surplus green time. Optimal green time calculated by estimated traffic volume from vehicle arrival model. Surplus green time defined as the gap of optimal green time and queue dissipated time. And alternative cycle has minimum surplus green time was selected as the optimal cycle. Finally, total delay and average delay per vehicle can be calculated by using queueing theory.

• Journal of Korean Society of Transportation
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• v.14 no.4
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• pp.91-106
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• 1996

This paper deals with on the efficiency questions of the left-turn prohibit at an isolated intersection and a corridor with 5-phase signal system. Its objectives are three-fold ; (1) to analyze the efficiency of the left-turn prohibit with the use of an imaginary network, (2) to evaluate various factors under consideration in decision making on the left-turn prohibit, (3) to provide a framework for estimating and evaluating overall impacts of the left-turn prohibit in traffic network. the major findings using an imaginary network and computer packages such as MINUTP, TRANSYT-7F and STATGRAPH are followings. First, left-turn prohibit reduces cycle length by 33 seconds and delay time per vehicle by 36 seconds at an isolated intersection, and cycle length by 31 seconds and delay time per veicle by 43 seconds along a corridor. Second, total vehicle mile of travel and total travel time at an isolated intersection seem up to increase 38.85 miles(57.36km), 14.4 hour on the average, Regarding to a corridor, total vehicle mile of travel is increased by 50.14 miles(80.22km), but total travel time is decreased by129.9 hours. Third, the efficiency of left-turn prohibit are affected the following eight factors including left-turn volume(veh/hr) and ratio(%), average delay time per vehicle(sec/veh) and others. Finally, several simple and multiple regression models to evaluate the impacts on the left-turn prohibit are formulated from the above eight factors. It can be expected that these models will take an important role in decision-making of left-turn prohibit.

• International Journal of Highway Engineering
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• v.15 no.5
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• pp.217-226
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• 2013

PURPOSES : Under the capacity conditions with balanced approach flows, roundabouts give less delay than existing signalized intersections; however, flows over 450 vehicles/hour/lane with unbalanced approach flow conditions, roundabouts efficiency drops due to the short time difference between the critical gap and the follow-up headway. The purpose of this study is developing a roundabout Signal Metering operation method by considering approach lanes degree of saturation. METHODS : A four-way-approach with one-lane roundabout is selected to compare the Signal Metering performance for the case of 16 different unbalanced flow conditions. Based on these traffic conditions, the performance is evaluated for 64 different cases of Signal Metering combinations by using SIDRA software. A degree of saturation(V/C ratio) sum for two adjoined approaches is used for the performance index of choosing Metered Approach and Controlling Approach. RESULTS : When the V/C ratio sum is 0.29~0.81 and Metered Approach flow is less than Controlling Approach flow, the average delay saving per vehicle is about 7 seconds; however, after this rage the delay saving decreases gradually until the V/C ratio sum reaches around 1.0. The range of V/C ratio sum 0.93~1.09 provides average delay saving per vehicle about 3 seconds. In case of V/C ratio sum is grater than 1.0 and the flows of Metered Approach is grater than Controlling Approach, the average delay per vehicle increases 3~11 times respectively. CONCLUSIONS : As expected, the Signal Metering provides substantial improvements in delay saving for the case of V/C ratio sum is 0.3~1.0 under the traffic flow conditions of Metered Approach is less than Controlling Approach.

• International Journal of Highway Engineering
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• v.12 no.4
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• pp.29-37
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• 2010

This study deals with the Right-Turn Bypass Lane in Roundabout. The purpose of the study is to comparatively analysis the effectiveness questions on the installation of right-turn bypass lane in roundabout. In pursuing the above, this study analyzed after and before of the right turn bypass lane plan by VISSIM software. The right turn bypass lane is formed by control type of yield and control type of joint were compared and analyzed the effects of the operation. The main results analyzed are as follows. First, after Right-Turn Bypass Lane is Installed, the traffic volume rate of the right-turn increasing by average delay time per vehicle is on the gradual decrease, maximum average about 28% with the fact that decreases. Second, control type of yield and control type of joint are both average delay time per vehicle decreasing by the traffic volume rate of the right-turn is on the gradual increase. Control type of joint was analyzed with the fact that has the maximum average about 18% delay decrement efficiency.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.10 no.6
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• pp.24-31
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• 2011

This study deals with the operational effectiveness of roundabout. The roundabout is currently under consideration in our country depending on the result of existing researches, that the roundabout decreases delay and is environmentally friendly compared to the signalized intersection. The purpose of the study is to analyze the operational effectiveness of the roundabout by the change of pedestrian traffic volume. In pursing the above, this study gave particular emphasis to designing a network of roundabout, developing some scenarios for analysis including both entering traffic volume and pedestrians volume, and comparatively analyzing the average controlled delay time per vehicle. In this study, VISSIM model was used as a tool for traffic simulation. The main results are as follows. First, as a result of analyzing a traffic delay based on the pedestrian traffic volume, pedestrian traffic volume was analyzed to have a great impact on the roundabout operation. Second, the more pedestrian traffic volume were evaluated to indicate the more traffic delay. When the entering volumes with 1,000persons/hour (pedestrian volume) were more than 800pcph in the single-lane and 1,600pcph in the double-lane roundabout, the operational efficiencies of signalized intersections were evaluated to be better than those of roundabouts.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.11 no.4
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• pp.1-9
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• 2012

This study deals with the operation effectiveness of roundabout. The objective of this study was to analyze the operational effectiveness of roundabout based on the operation of pedestrian signal. For pursuing the above, VISSIM was as a traffic simulation program. this study gives particular attention to analyzing the 1,680 scenarios by operation of Pedestrian Signal(7 cases), roundabout type(2 cases), pedestrian volume(8 cases) and entering volume(15 cases). The main results analyzed are as follows. First, the operational effectiveness analyzed by 2 type of 4-legged 1-lane roundabout and 6 type of 4-legged 2-lane were evaluated to be better than that by the others type. Second, the average delay time analyzed by operation of pedestrian signal were evaluated to be less than that by unsignalized pedestrian crossing. Finally, the average delay time analyzed by pedestrian crossing were decreased 8.18% than that by staggered pedestrian crossing in 4-legged 1-lane. However, the average delay time analyzed by staggered pedestrian crossing were evaluated to be decreased 36.53% than that by pedestrian crossing in 4-legged 2-lane.

• International Journal of Highway Engineering
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• v.13 no.2
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• pp.77-83
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• 2011

This study deals with the effectiveness of roundabout. The goal is to comparatively analyze the operational effectiveness related to the conversion of rotary to roundabout in Korea. In pursuing the above, this study gives particular attentions to investigating the existing 20 rotaries and developing the networks of before-and-after improvement using VISSIM, and comparatively analyzing the effectiveness. The domestic rotaries were analyzed to need many improvements of geometric structure for the effective operation of roundabout. The main results are as follow. First, when the present condition of traffic volume were applied, the operational effect of rotary were evaluated to be better than roundabout, but the difference analyzed to be small. Second, the average delay per vehicle in the rotaries of urban area were analyzed to rapidly increase according to the growth of traffic volume. Finally, the average speed of roundabout were evaluated to be less (about 10km/h) than that of rotary, because the traffic volume of rural area were less than that of urban area.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.17 no.6
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• pp.133-143
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• 2018

Roundabouts are generally installed at which traffic and pedestrian volume is relatively small intersections, and hence traffic can flow one direction around a circular island without traffic lights. A number of researches for roundabout signal metering have been processing ways to deal with operation efficiency drops in conditions of unusual traffic and pedestrian volume increases. However, there is still a shortcoming exists in previous operation algorithm does not consider the hidden vehicles between yield lines and detectors and queueing vehicles in circular lanes. These queueing vehicles between them can be cleared by introducing the queue clearance time. The purpose of this research is developing a real time signal metering operation algorithm by considering the vehicle queue clearance time. The results of varying queue clearance time application show that there is a substantial average vehicle delay reduction in VISSIM Com-Interface simulation. When the total number of entering vehicle is 3,200~4,800 vehicle/hour with varying queue clearance time application 21~50 seconds gives average delay reduction per vehicle by 16.1~71.7%.

• International Journal of Highway Engineering
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• v.11 no.3
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• pp.121-128
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• 2009

This study has proposed the signal operating system to use both semi-actuated signal control and pedestrian push-button as a way to make up for the problems of 3 leg intersections which are operated inefficiently in the signal operation, one of the methods of traffic operations. In case of the semi-actuated signal control, it can reduce delay inside the intersection by serving to uncongested traffic on the main road where there is not much traffic volume on the secondary road and push-button signal can reduce unnecessary waiting time it could happen to vehicles by operating it though there is no pedestrian. Quantitative analysis was tried regarding the average delay reduction per vehicle using VISSIM, microscopic simulation program regarding how much effect it has compared with the existing signal control system and semi-actuated signal control system when the above two advantages are collected. The field test was performed for one three-leg intersection of Incheon. According to respectively signal control method pedestrian traffic changed and executed a sensitivity analysis. The result which compares the average delay time per a vehicle of scenarios, the signal control method of using the pedestrian push-button system in comparison with the fixed signal control method showed to decrease effect of a minimum 3.7 second (10%), a maximum 5.8 second (16%). When the pedestrian traffic volume was 20% or less of the measurement traffic volume, The signal control method of using the pedestrian push-button system appeared to be more efficient the semi-actuated signal control with object intersection.

• Journal of Korean Society of Transportation
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• v.25 no.6
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• pp.185-196
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• 2007

The aim of this research is to develop a signal control algorithm using internal metering to minimize total delay that vehicles go through, in case a network is oversaturated. To calculate total delay on the network, the authors first detect vehicles' arrivals and departures in the network through the detecting system, and chase the vehicles' flow in the links with a platoon dispersion model. Following these, the authors calculate the queue length in all the inks of the network through the chase of vehicles, deduce the stopped time delay, and finally convert the stopped time delay to the approach delay with a time-space diagram. Based on this calculated delay, an algorithm that calculates the level of the internal metering necessary to minimize the deduced approach delay is suggested. To verify effectiveness of this suggested algorithm, the authors also conduct simulation with the micro-simulator VISSIM. The result of the simulation shows that the average delay per vehicle is 82.3 sec/veh and this delay is lower than COSMOS (89.9sec/veh) and TOD (99.1sec/veh). It is concluded that this new signal control algorithm suggested in this paper is more effective in controlling an oversaturated network.