• Journal of Korean Society of Transportation
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• v.25 no.2 s.95
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• pp.73-81
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• 2007

The purpose of this paper is to perform a basic study on the interaction between lanes, which can be achieved through analyzing traffic breakdown at the microscopic level. Using aerial photographic data for the microscopic analysis, this study analyzed the characteristics of traffic flow at a merging area. This research produced aggregated traffic data such as flows, speeds, and densities in 30 second intervals by lane for the macroscopic analysis and individual headway data by lane for the microscopic analysis. The paper contains an analysis of lane characteristics through flows, speeds, densities, and headway variations and also investigates the influence of ramp flows on mainline flows with space-time diagrams. Firstly, the merging area in this study is divided into three sections: before-merging, during-merging, and after-merging. The transition process was analyzed at each lane. Secondly, the breakdown was observed in detail with data divided in 50-foot units. The breakdown was checked through the relationships between ramp and freeway mainline flows, various techniques were proposed to analyze the breakdown, and the formation of breakdown was introduced as three stages in this study. In the near future, the findings of this study could contribute to determining the dynamic capacity on freeways by easily understanding changeable traffic breakdown patterns over time and space.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.7
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• pp.575-583
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• 2017

This paper describes the design and evaluation of a driving mode decision algorithm for automated driving for merge situations on highways. For the development of a highly automated driving control algorithm for merge situations, the driving mode decision is crucial for merging appropriately. There are two driving modes: lane keeping and lane changing (merging). The merge mode decision is determined based on the state of the surrounding vehicles and the remaining length of the merge lane. In the merge mode decision algorithm, merge possibility and the desired merge position are decided to change the lane safely and quickly. A safety driving envelope is defined based on the desired driving mode using the information on the surrounding vehicles' behaviors. To obtain the desired steering angle and longitudinal acceleration for maintaining the subject vehicle in the safe driving envelope, a motion planning controller is designed using model predictive control (MPC), with constraints that are decided considering the vehicle dynamics, safe driving envelope, and actuator limit. The proposed control algorithm has been evaluated via computer simulation studies.

• Journal of Korean Society of Transportation
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• v.32 no.5
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• pp.473-486
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• 2014

This study aims to review whether climbing lane installment is needed by analyzing the impact that standard trucks have on traffic according to vertical alignment at SMART highway, and if climbing lanes are required to propose truck speed change curves based on slope length. We used VISSIM simulation model to obtain the speed change of the standard truck on uphill roads. The standard truck on climbing lanes was set for 100kg/kW (170lb/hp) with the entry speeds set and analyzed by 90, 100, and 110 km/h considering the future speed limit of trucks. The results of the research show that under SMART highway circumstance, the 1 and 2% vertical alignment is not needed at the climbing lane but 3% vertical alignment is necessary. In order to install the climbing lane at 3% vertical alignment, the speed change curve of truck depending on slope length of 90, 100, and 110km/h of entry speed is proposed.

• Journal of Korean Society of Transportation
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• v.31 no.2
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• pp.3-10
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• 2013

Two-lane roads that occupy more than a half of rural highways in Korea have operational problems such as traffic congestion problems due to relatively high traffic volume and safety problems due to overtaking risks in two-lane highways. To solve these problems, a 2+1 road pattern that enables to improve traffic safety and operational efficiency of two-lane highways has been applied in Europe. In this study, in-depth applicability of 2+1 roads to Korean rural highways was investigated based on review results of the successful experience of European 2+1 roads. Then, given the Korean two-lane highway conditions, the service traffic volumes for Korean 2+1 roads was estimated. The analysis results showed that 17,000 veh./day might be the maximum traffic volumes for Korean 2+1 roads.

• Journal of Digital Convergence
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• v.14 no.8
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• pp.253-259
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• 2016

Regarding the research on lane recognition, continuous studies have been in progress for vehicles to navigate autonomously and to prevent traffic accidents, and lane recognition and detection have remarkably developed as different algorithms have appeared recently. Those studies were based on vision system and the recognition rate was improved. However, in case of driving at night or in rain, the recognition rate has not met the level at which it is satisfactory. Improving the weakness of the vision system-based lane recognition and detection, applying sensor convergence technology for the response after accident happened, among studies on lane detection, the study on the curve road detection was conducted. It proceeded to study on the curve road detection among studies on the lane recognition. In terms of the road detection, not only a straight road but also a curve road should be detected and it can be used in investigation on traffic accidents. Setting the threshold value of curvature from 0.001 to 0.06 showing the degree of the curve, it presented that it is able to compute the curve road.

• Journal of Korean Society for Atmospheric Environment
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• v.34 no.4
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• pp.542-553
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• 2018

Since many previous studies reported the health effect of air pollution and indicated traffic as a major pollution source, significant policy efforts have been made to control traffic to reduce air pollution. However, there have been few studies that evaluated such policy implementation. In Seoul, Korea, the exclusive median bus lane system was implemented in 2004, and the metropolitan government applied air pollution reduction policies such as conversion of diesel buses to compressed natural gas buses and installation of emission control devices. This paper aimed to investigate the impact of the exclusive median bus lane system on air pollution reduction. Using hourly concentrations of particulate matter ($PM_{10}$) and nitrogen dioxide ($NO_2$) measured at 131 regulatory monitoring sites in Seoul and Gyeonggi-do for 2001-2014, we calculated annual and daily average concentrations at each site. We assessed the impact of the policy using differences-in-differences analysis by annual and daily average models after adjusting for geographic and/or meteorological variables. This method divides population into treatment and control groups with and without policy application, and compares the difference between the two time periods before and after the policy implementation in the treatment group with the difference in the control group. We classified all monitoring sites into treatment and control groups using two definitions: 1) Seoul vs. Gyeonggi-do; 2) within vs. outside 300 meters from the median bus lane. Pre- and post-policy periods were defined as 2001-2005 and 2006-2014, and 2004 and 2014 in the annual and daily models, respectively. The decrease in $PM_{10}$ concentrations between the two periods across monitoring sites in the treatment group was larger by $1.73-5.88{\mu}g/m^3$ than in the control group. $NO_2$ also showed the decrease without statistical significance. Our findings suggest that an efficient public transport policy combined with pollution abatement policies can contribute to reduction in air pollution.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.8 no.5
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• pp.57-70
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• 2009

According to the change of the traffic conditions, the requirement of controlling the separated left(or right) turn, the median bus lane and bicycle signal is increasing. However, the traffic signal controller standard based on the four-set lights restricts to control the three-set lights which control the separated direction and kind of traffics. This study suggests the method to control the three-set lights signal by improving the hardware and software for the traffic signal controller which is operated currently in the traffic scene. The 6 output ports of Load Signal Unit(LSU) which is consisted of Pedestrian Red, Pedestrian Green, Red, Yellow, Arrow and Green signal reconstitute 2 rows of the Red, Yellow, Green for three-set lights while the Signal Map data's code values which control the signal step of an individual Ring and LSU are established to adjust the LSU's output ports(R1 Y1 G1 R2 Y2 G2) of the three-set lights. The effect of using the separated through/left turn and the median lane bus signal of three-set lights is analyzed from a Mangwoo intersection in Seoul. The results of analysis show that the delay time of the east-west direction where the median bus lane is operated is especially improved with over 70 sec/veh.

• Journal of Advanced Navigation Technology
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• v.22 no.6
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• pp.566-576
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• 2018

The C-ITS requires the lane level positioning of the vehicle in the land transportation environment, and it is most effective to utilize the GNSS. In the precision positioning system based on satellite navigation, the evaluation of dynamic environment of lane level positioning performance should be accompanied and the evaluation system configuration should be preceded. In this paper, we selected performance indicators, assessment equipment, and reliability of reference equipment for evaluation of precision positioning user systems based on the GNSS. The performance evaluation system described above is applied to a real system, and the performance evaluation tool developed for the evaluation system is described. The numerical performance evaluation was carried out based on the data collected by carrying out the actual testbed driving. The performance evaluation by the actual driving trajectory and driving image comparison was performed to derive and analyse the evaluation results of the vehicle lane level positioning user system.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.39 no.6
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• pp.363-369
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• 2021

High-definition road maps are used as the basic infrastructure for autonomous vehicles, so the latest road information must be quickly reflected. However, the current drawing and structural editing process of high-definition road maps are manually performed. In addition, it takes the longest time to generate road lanes, which are the main construction targets. In this study, the point cloud of the road lane markings, in which color types(white, blue, and yellow) were predicted through the PointNet model pre-trained in previous studies, were used as input data. Based on the point cloud, this study proposed a methodology for automatically drawing and structural editing of the layer of road lane markings. To verify the usability of the 3D vector data constructed through the proposed methodology, the accuracy was analyzed according to the quality inspection criteria of high-definition road maps. In the positional accuracy test of the vector data, the RMSE (Root Mean Square Error) for horizontal and vertical errors were within 0.1m to verify suitability. In the structural editing accuracy test of the vector data, the structural editing accuracy of the road lane markings type and kind were 88.235%, respectively, and the usability was verified. Therefore, it was found that the methodology proposed in this study can efficiently construct vector data of road lanes for high-definition road maps.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.2
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• pp.219-230
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• 2023

Cities are continued to be highly advanced and metropolitanized. Lands adjacent to road make entry/exit connection increase along with construction of facilities for various purposes. However, in the absence of specific installation standards of entry and exit connection, inappropriate access location, types of access, and operation methods are deteriorating the level of traffic services at existing roads and intersections. Therefore, in order to minimize the traffic impact from entrances connected to minor arterial roads and colletor roads, first, this study re-established the waiting length in the intersection of upstream and downstream and length required for changing lanes and between entrance/exit and connection, considering the road and traffic environment in contact with the entrance. Second, it is suggested that the operation method depending on the connection type and whether to install left turn lane and acceleration and deceleration lane can be determined quantitatively by relation with the service level of nearby intersection after calculating the threshold amount of business site through negative social cost, which is the difference between the installation cost of the left turn lane and the acceleration and deceleration lane according to the type of access to the entrance and exit.