• Journal of Korean Society of Transportation
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• v.11 no.1
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• pp.23-36
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• 1993

The two-lane, two-way highway simulation program(TWOPAS) is evaluated for Korean Highway Capacity Manual Study. TWOPAS program input variables, especially related vehicle performance, traffic flow relationship, car-following model and passing logic are examined and modified through the analysis results of our two-lane, two-way highway traffic characteristics. Simulation outputs with and without modification are compared with the field data. The results show that improved TWOPAS program(TWOPAS KI) is well suitable for simulating our two-lane, two-way highway condition.

• International Journal of Highway Engineering
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• v.15 no.3
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• pp.85-92
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• 2013

PURPOSES: The purpose of this paper is to estimate expected effects on traffic operational and economic aspects of 2+1 roads application in Korea. METHODS : Micro simulation study using VISSIM 5.0 was used to analyze the operation efficiency of 2+1 roads compared to two-lane highways and four-lane highways. Some scenarios for various traffic volumes were set up in order to analyze the effect of 2+1 roads under various traffic situations. Also imaginary road networks were set up for each type of roads. The MOEs to measure the operation efficiency were selected with average travel speed and delay. For analyzing economic effect of 2+1 roads, construction cost of a specific imaginary 2+1 road was compared to construction cost of a four-lane highway with same conditions. RESULTS: The results of study show that a 2+1 road is more effective with 19 percents higher average travel speed and 39 percents lower average delay than a two-lane highway. In the economic analysis, construction costs to construct a 2+1 road are saved as approximately 26.4~40.7 percents when compared to construction of four-lane highway. CONCLUSIONS: It can be concluded that 2+1 roads can improve the traffic operational level of service for two-lane highways and 2+1 roads can be applied as an effective design alternative for higher-volume two-lane highways in Korea.

• International Journal of Highway Engineering
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• v.18 no.6
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• pp.11-24
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• 2016

OBJECTIVES : This study aims to review a plan to reduce the shoulder width of a deformed round-trip two-lane highway with low traffic volume. METHODS : Installation of a passing lane on a round-trip two-lane (one-way one-lane) highway, and reduction of a shoulder for a round-trip four-lane highway. RESULTS : It is necessary to establish a design criterion for various highways, because the plan to reduce the lane or shoulder width of a highway with low traffic volume was analyzed to have an economic efficiency of 6.8~7.0%. CONCLUSIONS : It is necessary to seek for a plan to establish a national trunk net early by efficiently using the limited financial resources to cope with the traffic demand elastically.

• International Journal of Highway Engineering
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• v.14 no.6
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• pp.131-138
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• 2012

PURPOSES : Two-lane highways have one lane in each direction, and lane changing and passing maneuvers take place in the opposing lane depending on the availability of passing sight distance. 2001 Korea Highway Capacity Manual (KHCM) is classified into two classes of two-lane highways (Type I, II), and average travel speed and time-delayed rate are used as measures of effectiveness (MOEs). However, since existing two-lane highways have both uninterrupted and interrupted traffic flow-system elements, a variety of free-flow speeds exhibits in two-lane highways. In addition, it is necessary to check if the linear-relationship between volumes and time-delayed rate is appropriate. Then, this study is to reestablish the relationship between average travel speed, time-delayed rate, and flow. METHODS : TWOPAS model was selected to conduct this study, and the free-flow speeds of passenger cars and the percentage of following vehicles observed in two-lane highways were applied to the model as the input. The revised relationships were developed from the computer simulation. RESULTS : In the revised average travel speed vs. flow relationship, the free-flow speed of 90km/h and 70km/h were added. It shows that the relationship between time delayed-rate and flow appeared to be appropriate with the log-function form and that there was no difference in time-delayed rate between the free flow speeds. In addition to revise the relationships, the speed prediction model and the time-delayed rate prediction model were also developed. CONCLUSIONS : The revised relationships between average travel speed, time-delayed rate, and flow would be useful in estimating the Level of Service(LOS) of a two-lane highway.

• International Journal of Highway Engineering
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• v.19 no.6
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• pp.183-190
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• 2017

PURPOSES : The objective of this study is to establish the traffic volume-based warrants of right-turn lanes at unsignalized intersections and to introduce a risk probability methodology based on the warrants. METHODS : In this study, a risk probability of a potential rear-end collision is applied between a right-turn vehicle and the immediately following through vehicle. Using the shifted negative exponential model and the compound probability theorem, the risk probability can be expressed as the function of directional volumes and the percentage of right-turns for a two-lane and four-lane highway, respectively. RESULTS : Based on the risk probablity, guidelines for installing right-turn lanes on two-lane and four-lane highways were developed. The risk probability also showed rationality by comparing with right-turn same-direction conflicts observed in-situ. CONCLUSIONS : The results of our study define the total approaching volumes to encourage a right-turn lane as a function of operating speed, percentage of right-turn, and number of lanes.

• International Journal of Highway Engineering
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• v.10 no.3
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• pp.33-46
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• 2008

A two-lane highway has a high rate of head-on collisions, sideswipe collisions, crashes with an fixed object. This study was to analyze the weakness of a cross section and a horizontal curve in a two-lane highway and find countermeasures to improve the traffic operations and safety. This study evaluated the effectiveness of widening, curve flattening and superelevation, verified it with a case study and assessed the economical efficiency. This study selected the difference between tangent section operating speeds and curve section operating speeds as an evaluation index of horizontal curve section in a two-lane highway. The results indicated that curve flattening is the best way to improve the traffic safety in a two-lane highway. This study has implication that it provides the quantitative effects of curve flattening. Also directions for future study were discussed.

• International Journal of Highway Engineering
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• v.8 no.2 s.28
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• pp.75-85
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• 2006

Currently, cross-section design can not reflect highway function and traffic volume, various construction. This research paper provides analysis of traffic accident type, improvement of traffic operation and safety, assessment for new cross-section standards of two-lane highway. Research show higher accident rate on 6$\sim$8.9m road than 9$\sim$12.9m road width in two-lane highway. Typical improvement is widening on lane and shoulder width. Simulation show large increase on 6$\sim$7m road delay-time in 1,200vph. In contrast 10$\sim$11.5m road shows slight change on delay-time. This research paper provides various cross-section construction by traffic volume in minor arterial and distributor two-lane highway. The new cross-section design provides adopting highway volume, various construction and flexibility.

• Journal of Korean Society of Transportation
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• v.11 no.3
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• pp.67-82
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• 1993

The effects of passing lanes on traffic flow on rural two-lane highways have been investigated in this research. Field study results were compared with the computer simulation model, TRARR, TRARR model appears to be in good agreement with field study results except that average speed and distribution of platoon sizes showed a small amount of discrepancy, which is believed to be caused by too large a headway definition of 6 second for a vehicle platoon. Using the TRARR model, 4 situations including the existing condition, installation of passing lanes, improvement of design speed, and expansion to a four lane highway were evaluated. Traffic volume levels of 500,1000, and 1500 vph and truck composition of 20 and 40% were also considered making a total of 24 computer runs. It is concluded in this research that the installation of passing lanes is the most effective method to improve traffic operation on two-lane high ways except the alternative of four lane highway expansion.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.10 no.5
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• pp.124-134
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• 2011

To make popular the NEV(Neighborhood Electric Vehicles) uses, it must be considered the supply of infrastructure and the political decision for NEV. However, the guidelines of infrastructure for NEV are not prepared. The guidelines of infrastructure for NEV should be performed in many research and case. The purpose of this study is to reveal the influence of NEV on the two-lane highway traffic flows by TWOPAS simulation model. The main items to check the influence are Average Travel speed, Percent Time Spent Following and Total Delay. The scenario were setup by traffic volume. And the NEV percentages are changed from 1% ~ 30%. The scenario 1 which traffic volume are 650veh/h and the scenario 4 which traffic volume are 2,600veh/h are less influenced by NEV, compare to scenario 2, scenario 3. Because the scenario 1 is more free to make passing other cars and Scenario 4 is fully saturated with existing traffic volumes. The urban two-lane highway which has much traffic volume and the rural two-lane highway which has little traffic volume has affinity for NEV than the other two-lane highway.

• Journal of Information Technology Applications and Management
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• v.11 no.4
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• pp.169-179
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• 2004

There are many inductive loop detectors under the highways in Korea. Among the other detectors, some are image detectors. Almost all image detectors are focused one or two lane of the road and are measuring traffic information. This paper proposes to an algorithm for detecting traffic information automatically from CCTV camera images installed on the highway. The information which is counted in one lane or two contains some critical errors by occlusion frequently in case of passing larger vehicles. In this paper, we use a tracking algorithm in which the detection area include all lanes, then the traffic informations are collected from the vehicles individually using difference images in this detection area. This tracking algorithm is better than lane by lane detecting algorithm. The experiment have been conducted two different real road scenes for 20 minutes. For the experiments, the images are provided with CCTV camera which was installed at Kiheung Interchange upstream of Kyongbu highway, and video recording images at Chungkye Tunnel. For image processing, images captured by frame-grabber board 30 frames per second, 640${\times}$480 pixels resolution and 256 gray-levels to reduce the total amount of data to be Interpreted.