• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.17 no.3
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• pp.59-71
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• 2018

This study was initiated to develop an optimal signal control algorithm for coordinated signalized intersections using individual vehicle's information which can be collected in a format of prove vehicle data (PVD) via V2I (Vehicle to Infrastructure) communication environment. For developing this signal optimization algorithm, three modules were developed for phase group length computation, split distribution, and phase sequence assignment. The simulation analysis using the microscopic simulation model, Vissim, was conducted for evaluating the effectiveness of the developed algorithm. The analysis result represented that the performance of the developed algorithm is far superior to that of the fixed coordinated signal control method which is the most common signal control method for coordinated signalized intersections in Korea.

• International Journal of Highway Engineering
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• v.17 no.4
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• pp.89-98
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• 2015

PURPOSES : This study evaluated the feasibility of implementing protected-permissive left-turn (PPLT) signals at three-leg signalized intersections. METHODS: A three-leg signalized intersection with permissive left-turn was first selected. A VISSIM simulation model was constructed using data collected from the test site. The VISSIM network was calibrated by adjusting related parameter values in order to minimize the difference between the simulated and surveyed critical gap. The calibrated network was validated by the number of waiting left-turning vehicles per cycle. Finally, the mobility and safety measures were extracted from simulation runs in which permissive, protected left turns as well as PPLTs were realized based on diverse traffic volume scenarios. RESULTS : The mobility-related measures of effectiveness (MOEs) of the case with PPLT outperformed the other two left-turn treatment scenarios. In particular, the average waiting time per cycle for the left-turn vehicles in the case with PPLT was reduced by 30 s. The safety-related MOEs of the case with PPLT were somewhat higher than those in the case with protected left-turns and much higher than those in the case with permissive left-turns. CONCLUSIONS : Based on the mobility- and safety-related MOEs generated from the VISSIM simulation runs, the use of PPLT seems to be feasible at three-leg signalized intersections where the left-turn is permissive and a pedestrian signal exists at the conflicting approach. However, in order to use the PPLT in earnest, it is necessary to revise the road traffic act, traffic signs, and related manuals.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.2 no.1 s.2
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• pp.53-62
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• 2003

This paper demonstrates the in-vehicle dilemma zone warning system (DZWS) project developed as a part of the Driver Advisory and Collision Warning System in Automated Vehicle and Highway System (AVHS). The DZWS project, one of the Korea national ITS projects in 2000 develops the in-vehicle warning device to support drivers' decision making on whether to stop or to proceed to clear the intersection prior to the onset of yellow signal for avoiding the high risk of collision at signalized intersections through the dedicated short range communication (DSRC). This paper explores the design of optimal communication systems between roadway and vehicles, the operational and functional concepts of dilemma zone warning system based on appropriate approach speeds, and the system integration for field test at two sites of signalized intersections. Findings from the system integration indicated that the system would be implemented in eliminating the dilemma zone relative to approach speeds and in reducing red light violations and intersection collisions through the in-vehicle warning device at signalized intersection.

• International Journal of Highway Engineering
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• v.12 no.3
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• pp.49-57
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• 2010

This case study investigated red light violations at CBD, suburban and rural signalized intersections in chungbuk. The goal of this study is to understanding the collection between red light violations and various driver, vehicles and environmental factors. This study uses descriptive statistics analysis and logistics analysis with SPSS 12.0 software. The major results of this study are as follows. First, red light violations occurred at rural and CBD more than suburban area. Second, About 81.1% of the violators were traveling at or below the posted speed limit. Moreover, 77.3% of the violations occurred within 2 seconds after the on set of red light. Finally, the logistic regression model, which is statistically significant(chisquare=0.000, McFadde=0.265)was developed, and includes the local type(CBD/suburban/rural), violators' gender, season, vehicle type, time of day, vehicle speed as the independent variables. In this study did not find significant relationship between red light violators' age and their driving behavior approaching signalized intersections.

• Journal of Korean Society of Transportation
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• v.21 no.4
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• pp.7-16
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• 2003

Objective of this research is to analyze drivers' behaviors at signalized intersection during yellow interval. For this, deceleration rate of stopping, PRT(Perception-Response Time), and the relationship between dilemma zone and deceleration rate of stopping were surveyed at two signalized intersections located at urban area(Songtan and Suwon) and local area(Yongin) As a result, the deceleration rate of stopping at signalized intersections and a range of dilemma zone were estimated. It was found that the deceleration rate of stopping and PRT were 1.6m/sec$^2$ and 1.27sec, respectively. These values are bigger than ITE's values which have been used in our country. Accordingly, it is considered that these values should be used as a new design criteria for the traffic signal control.

• 한국ITS학회:학술대회논문집
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• 2002.11a
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• pp.39-42
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• 2002

• International Journal of Highway Engineering
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• v.10 no.4
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• pp.199-211
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• 2008

This study deals with the side right-angle collisions of 4-legged signalized intersections in Cheongju. The goals are to analyze the characteristics of accidents and to find out the accident factors that affect severity using ordered probit model. In pursuing the above, the study uses the data of 580 side right-angle collisions occurred at the 181 intersections(2004-2005). The analyses show that more accidents were occurred in the nighttime and in going straight. The main cause was analyzed to be the red-light violation. Also, the main results of modeling are the following, First, the likelihood ratio index is 0.094 and t-ratio values that explain goodness of fit are significant. Second, minor road traffic volumes, minor road lanes, major road left-turn lanes, major road left-turn signal, major road yellow signal time, cross angle, major and minor road speed limits are significant factors affecting crash severities at signalized intersections.

• International Journal of Highway Engineering
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• v.9 no.3
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• pp.83-89
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• 2007

When allocating traffic signal at the signalized intersection, minimum green time and clearance time for bicyclists should be significantly considered in order to enhance safety aspects to bicyclists when crossing intersections, especially where intersections with exclusive bicycle paths that are physically separated from pedestrians. In this study, field measurements related to bicycle crossing time, including minimum peen time and clearance time, were collected and analyzed according to bicycles crossing types at the signalized intersections where high rate of bicyclists exists. Three types of bicycle crossing are defined as follows 1) stopping: completely stop before crossing (at least one foot on found) 2) riding: crossing with riding bicycle 3) pulling: crossing without riding bicycles. Minimum green time based on pedestrian speeds should be used as crossing time in this case. For bicyclists, speed of bicycle that is applicable to estimate the minimum green time is in the 1.36m/sec($15^{th}$ percentile) to 1.60m/sec($25^{th}$ percentile) range in case of its stopping. Also it is in the 0.75($15^{th}$ percentile) to 0.87($25^{th}$ percentile) range for pulling at crosswalk. In addition, speed of bicycle to consider for calculating the clearance time is in the 2.51m/sec($15^{th}$ percentile) to 2.79m/sec($25^{th}$ percentile). These values also resulted from $15^{th}$ percentile or $25^{th}$ percentile speeds of riding. The results of this study are expected to be supported in traffic signal allocation process, reflecting bicyclists' characteristics.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.8 no.2
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• pp.27-35
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• 2009

The roundabout was developed in the United Kingdom to rectify problems associated with these traffic circles. In 1966, the United Kingdom adopted a mandatory "give-way" rule at alt circular intersections, which required entering traffic to give way, or yield, to circulating traffic. However, the roundabout used in United States or Europe do not common use in Korea. The purposes of the study is to comparatively analyze the effectiveness of roundabout. In pursuing the above, this study designs the scenarios which can reflect the directional traffic volumes, and analyzes the average control delay of roundabout and 4-leg signalized intersection by SIDRA. The main study results are as follows. First, when the entering traffic volume are less than 2,000pcph, the single-lane roundabout is analyzed to be more effective than 4-leg signalized intersection. Second, when the entering traffic volume are less than 3,200pcph, the double-lane roundabout is evaluated to be more effective than 4-leg signalized intersection. Third, which is installed left and right turn lane at intersection, area for the roundabout is analyzed to be less than that for general intersection area.

• Journal of Korean Society of Transportation
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• v.12 no.1
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• pp.117-132
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• 1994

Drivers select approach lane according to various traffic situations as well as their destination. This behavior affects the utilization of lanes and capacity analysis at urban signalized intersections. This paper presents the concept, behavior of lane utilization, and the lane utilization factors which included in the study. Preparation of Korean Highway Capacity Manual (1992). Lane utilization is affected by various traffic and geometric factors which are roadway side friction, median friction, and number of lanes, etc. and it converges to an equal utilization as the degree of saturation (V/C ratio) increase. Lane utilization factor is suggested by the degree of saturation and the number of lanes, and it is presented in this paper.