• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.12 no.6
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• pp.29-36
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• 2013

This study is the fundamental research to establish evacuation planning and to analyze evacuation planning characteristics in Gumi-city based on existing network and traffic characteristics data. Assuming an emergency situation, it compared with evacuation time estimates between using existing traffic signal system and proposed lane-based routing method through micro simulations. As a result, using existing traffic signal system could not affect the evacuation times in each level of emergency conditions. However this study found that proposed lane-based routing method is very effective to reduce an evacuation time compared with using existing traffic signal system. Also the proposed method is verified to reduce an evacuation time especially in extreme emergency circumstances.

• Journal of Navigation and Port Research
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• v.40 no.2
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• pp.51-56
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• 2016

Expressways mean the primary arterial highways with a high level of efficiency and safety. However, Gyeongbu and Namhae expressways connected with Busan ports are showing travel time delay by increased traffic including the medium/large-sized vehicles of about 20% compared to those of about 13% regardless of the peak periods. This study, thus, intends to analyze lane traffic characteristics in the basic 8-lane segments of the above-mentioned expressways, compute the planning and buffer times based on travel time reliability, find the lane speed showing a higher correlation with planning time between the lane speeds in the basic 8-lane segments, and finally suggest a correlation model for predicting the planning time in expressways.

• Journal of Navigation and Port Research
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• v.36 no.7
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• pp.591-597
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• 2012

Generally an urban freeway means a primary arterial which provides road users with a free-flow speed, except for ramp junctions during rush hours. However, most road users suffer from traffic congestion in the basic segments as well as in the ramp junctions of urban freeway during rush hours, because most road users prefer urban freeways to local roads in the urban areas. This study then intends to analyze lane traffic characteristics of urban freeway basic segments having more freight vehicles during rush hours, find the lane showing a high correlation with the segment speed between lane speeds, and finally suggest a segment-speed predictive model by the lane speed of urban freeway basic segments during rush hours.

• International Journal of Highway Engineering
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• v.17 no.5
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• pp.47-56
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• 2015

PURPOSES: The purpose of this study is to estimate the impact of variable message signage (VMS) on traffic safety as a function of road curve radius using statistical methods. METHODS: In order to analyze the impact of VMS installations on traffic safety, travel speed, lateral distance, and geometric data relating to road curvature in each study area was acquired and analyzed for the impact of providing VMS information on driver performance and traffic safety using statistical methods including student t-test, Mann-Whitney test, and the Anderson-Darling test for estimating traffic safety hazard zone in each lane. RESULTS: As a result of analyzing driver performance characteristics before and after providing VMS information, it was determined that by providing VMS information, mean travel speed is deceased and vehicles are driven with increased precision, following the centerline in the first and second lanes. Also the results of analyzing traffic safety impacts of VMS indicate that traffic safety performance factors in the first lane of the Gapyeong section can, on average, increase in the left and right side of the lane by 19.22% and 68.98%, respectively, and in the case of the second lane, safety impacts, on average, can increase in both sides by 100%. For the Hongcheon section, traffic safety impacts in the first lane, on average, can increase along the left and right sides of the lane by 32.31% and 47.18%, and within the second lane, traffic safety can be increased along the left and right side of the lane by 10.97% and -0.01%, respectively. CONCLUSIONS: Based on the results of this study, the impact on traffic safety obtained by providing VMS information for road sections with smaller curve radii is greater than can be obtained for road sections with larger curve radii.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.8 no.4
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• pp.170-181
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• 2009

When a slow-moving vehicle occupies one of the lanes of a multi-lane highway, it often causes queuing behind, unlike one is caused by an actual stoppage on that lane. This happens when the traffic flow rate upstream from the slow vehicle exceeds a certain critical value. This phenomena is called as the Moving Bottleneck, defined by Gazis and Herman (1992), Newell (1998) [3], and Munoz and Daganzo (2002), who conducted the flow estimates of upstream and downstream and considered slow-moving vehicle speed and the flow ratio exceeding slow vehicle and the microscopic traffic flow characteristics of moving bottleneck. But, a study of delay on moving bottleneck was not conducted until now. So this study provides a average delay time model related to upstream flow and the speed of slow vehicle. We have chosen the two-lane highway and homogeneous traffic flow. A slow-moving vehicle occupies one of the two lanes. Average delay time value is a result of AIMSUN[9], the microscopic traffic flow simulator. We developed a multiple regression model based on that value. Average delay time has a high value when the speed of slow vehicle is decreased and traffic flow is increased. Conclusively, the model is formulated by the negative exponential function.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.15 no.6
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• pp.116-126
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• 2016

In this study, lane-wise traffic flow characteristics were analysed on uninterrupted flow using a new notion of "lane-wise travel speed reversal (LTSR)" which is defined as a phenomena that travel speed in the median lane is lower than other lanes. Mathematical formulation was also proposed to calculate the strength of LTSR. The experiment road site is Seoul Outer Ring Expressway (Jayuro-IC~Jangsoo-IC), and travel trajectories for each four lane were collected for weekdays (Mon. through Fri.) during morning peak. Comparing lane-wise travel speeds for entire test road section, no LTSR was observed, meaning that the travel speed in the median lane is the fastest, followed by 2nd, 3rd, and 4th lane as in order. Howerver, the result of microscopic analysis using 100-meter discrete road section based data shows that LTSR occurs many times. Especially the strength of LTSR is higher in congestion area and freeway merge and diverge segment. It is expected that these results could be used as a fundamental data when establishing lane-by-lane traffic operation strategy and developing lane-wise traffic information collection and dissemination technology.

• International Journal of Highway Engineering
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• v.14 no.2
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• pp.109-116
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• 2012

This study is aiming to separate highway entrance ramps from impact zones which are considered the characteristics and real traffic situations in each lane and section. The results of this study can be applied to Lane Control System and control the traffic flow for highway more efficiently. Based on earlier studies which analyzed impact zones in entrance-ramp junction using the standard deviation of speed, this study divides more segmentalized impact zones according to the degree of turbulences. As a result of this study, about 800m of intervals, from 500m of upper flow (1,2,3 lane) to 300m of lower flow(2, 3 lane), shows similar traffic characteristics influenced by entrance ramp directly.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.6
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• pp.2473-2481
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• 2013

The two characteristics of two-lane-and-two-way traffic flow are platoon and overtaking triggered by low-speed vehicle. It is crucial to develop a robust model which simultaneously generates the behaviors of platoon by low-speed vehicle and overtaking using opposite lane. Hence, a microscopic two-lane and two-way vehicle model was introduced (B. Yoon, 2011), which is based on CA (Cellular Automata) which is one of discrete time-space models, in Korea. While the model very reasonably explains the behaviour of overtaking low-speed vehicle in stable traffic flow below critical density, it has shortcomings to the overtaking process in unstable traffic flow above the critical density. Therefore, the objective of this study is to develope a vehicle model to more realistically explain overtaking process in unstable traffic flow state based on the model developed in the previous study. The experimental results revealed that the car-following model robustly generates the various macroscopic relationships of traffic flow generating stop-and-go traffic flow and the overtaking model reasonably explains the behaviors of overtaking under the conditions of both opposite traffic flow and stochastic parameter to consider overtaking in unstable traffic flow state. The vehicle model presented in this study can be expected to be utilized for the analysis of two-lane-and-two-way traffic flows more realistically than before.

• International Journal of Highway Engineering
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• v.15 no.5
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• pp.135-144
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• 2013

PURPOSES : The purpose of this paper is to develop a methodology to estimate level of service of arterial including Exclusive Median Bus Lanes. METHODS : On 6 Exclusive Median Bus Lanes routes in Seoul, bus travel time and number of bus-stop per km were investigated. Also whether or not passing lane exists at bus-stop was checked. Based on the data from sites, bus travel time was estimated according to length of segment, number of bus-stop per km and whether or not passing lane exists at bus-stop. RESULTS : A bus travel time table was developed according to length of segment, number of bus-stop per km and whether or not passing lane exists at bus-stop. After bus travel speed and passenger car travel speed is estimated based on each travel time table and length of segment, two speeds are combined with weighted average speed using traffic volume of each lane group. Then weighted average speed is a measure of effectiveness of arterial including Exclusive Median Bus Lanes. CONCLUSIONS : It can be concluded that the proposed methodology can estimate level of service of arterial including Exclusive Median Bus Lanes considering the operation characteristics of Exclusive Median Bus Lanes.

• International Journal of Highway Engineering
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• v.17 no.4
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• pp.117-126
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• 2015

PURPOSES : This study aims to investigate the direct and indirect influence areas from incidents on urban interrupted roadways and to develop traffic management strategies for each influence area. METHODS : Based on a literature review, various traffic management strategies for certain incidents were collected. In addition, the relationship between the measure of effectiveness and the characteristics of incidents was explored using an extensive simulation study. RESULTS : From the simulation studies, traffic delays increased as the number of lane closures increased, and the impact of lane closures was reduced to the direction upstream from the incident site. However, the magnitude of the delay change depended on the degree of saturation. Using these characteristics, the direct and indirect influence areas resulting from incidents were defined, and traffic management strategies were established for each direct and indirect influence area and for each level of incident. CONCLUSIONS: The results of this study will contribute to the improvement of national traffic safety by preventing secondary incidents and by effective adaptation to incident events.