• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.2D
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• pp.205-216
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• 2008

Urban freeway is defined as the roadway with 4 lanes or more which requires a high design criteria for handling a large capacity of vehicles rapidly as a high-speed exclusive roadway in the city. However, most of the urban freeways suffer from severe traffic congestion due to the increased traffic exceeding their capacities regardless of the morning and afternoon rushhours or the inbound and outbound directions. The purpose in this study is to collect and investigate the real-time traffic characteristics based on the ramp junction influence areas of the urban freeway connected with the Busan port, compare and analyze the traffic characteristic relationship for each lane within the ramp junction influence areas, and finally assess and suggest the optimal capacity for each lane within the ramp junction influence areas.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.3D
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• pp.215-222
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• 2010

Average speed denotes a travel speed based on the average travel time of vehicles to traverse a segment of roadway, and average travel speed is used as a measure of effectiveness (MOE) suggested in the highway capacity manual (HCM) for evaluating the level of service (LOS) of roadway. Most of the urban freeways in our country are having congestion problem regardless of the rush hours as a high-speed highway with a speed limit of 80km/h or less. Especially traffic congestion within the ramp junction areas is becoming worse by the increased traffic and lack of links with the arterials around the urban freeway. So, the purpose in this study is to identify the traffic characteristics within the ramp junction areas of urban freeway, predict the average speed within the ramp junction areas based on the traffic characteristics identified, and finally prove the validity of the average speed predicted.

• Journal of Navigation and Port Research
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• v.26 no.1
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• pp.95-100
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• 2002

The first version of KHCM was Published in 1992 and is currently used in engineering Practice extensively. The study of new manual was initiated by Korea Institute of Construction Technology 1998 and is intended to be ready for publication by the year 2002. According to the field survey, the action of the individual merging vehicle creates turbulence in the vicinity of the ramp-freeway junction area. The purpose of this paper is to develop the model for Predicting the for entering the lanes 1 and 2($V_{12}$) and the density function at the influence zone by comがring the research works on the ramp junction in the USHCM 2000. The methodology has two major steps : the determination of the flow entering Lanes 1 and 2 immediately upstream of the merge influence area: and the density of the flow within the ramp influence area As a result of this paper the specific functions for such models are suggested through the regression analysis of data collected at four freeway fields in Korea.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.3D
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• pp.287-293
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• 2008

Density is used as the measure of effectiveness within the ramp junction influence area suggested in the KHCM 2005 in the LOS analysis of the ramp junction, and also density predictive models suggested in the KHCM 2005 is constructed based on the expressway with the speed limit of 100km/h or 110km/h in Korea. So, the density predictive models suggested in the KHCM 2005 are needed to verify if the models could be applied to the urban freeway with the speed limit of 80km/h or less, because the speed limits on most of the urban freeways in Korea are 80km/h or less. The purpose in this study is to construct and verify the appropriate density predictive model within the on-ramp merge influence area of the urban freeway by comparing with the USHCM 2000 and KHCM 2005 models.

• Journal of Korean Society of Transportation
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• v.31 no.5
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• pp.71-78
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• 2013

This paper investigated the influences of ramp traffic flow on the lane utilization for signalized intersection approaches which are adjacent to an off-ramp-street junction. The statistical test showed a correlation between lane utilization and the ramp traffic flow. As the ramp traffic flow increases, the left lanes are less utilized and the right lanes are more utilized. The lane utilization factors are calculated by applying traffic data collected from the Seoul Metropolitan area. The utilization factors are 1.113 for 2 lanes, 1.124 for 3 lanes, and 1.131 for 4 lanes. The lane utilization factors proposed in the paper show higher values than those in current Korea Highway Capacity Manual (KHCM) under the conditions that the number of lanes is 2 or 3. However, the lane utilization factor for 4 lanes in the paper shows lower value than in KHCM. The ramp traffic flow causes more utilization of the right lanes than at normal signalized intersections and the extent gets larger as the number of lanes decreases. Based on the results of the paper, the lane utilization factors at signalized intersection approaches should be revised and reasonable capacity should be recalculated if the signalized intersection is adjacent to an off-ramp-street junction.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.5D
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• pp.467-476
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• 2010

Travel delay (TD) denotes a time difference between the running time of vehicle with a normal speed and the travel time of vehicle with a reduced speed for traversing the same segment of roadway, and is sometimes used as a measure of time delayed in the junction or bottleneck areas of roadway. Urban freeways in the foreign countries are often suffering from traffic delay within the entrance and exit ramp junction influence areas, as a freeway with the speed limit of 80 km/h or higher only during the rush hours, but those in our country are especially experiencing severe traffic delay on the mainline segments as well as within the entrance and exit ramp junction influence areas, as a freeway with the speed limit of 80 km/h or less regardless of the rush hours. So, the purpose in this study is to develop the models that could predict the travel delay within the ramp junction influence areas of urban freeway having the geographical features which differ from the expressway, and also examine the validity of the travel delay predictive models developed.

• International Journal of Highway Engineering
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• v.15 no.1
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• pp.143-154
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• 2013

PURPOSES: Design of approach roads of rest areas in highway has many drawbacks such as geometric design elements. There has been traffic accidents occured in these approach roads of rest areas. Thus, design criteria is required in order to protect accidents from being occurred. In case of Korea, geometric structure design criteria of entry facilities, such as toll-gate, interchange, junction etc was established. However there are no presence in a detailed standards for geometric structure of the rest area which affiliated road facilities. METHODS: In this study, analytic on accidents was carried out in regards to the entry of geometric structure of resting areas by utilizing a sight survey and an investigation research of traffic accidents. The survey was targeting 135 general service areas. Collisions with physical channelization and safety facilities occurred due to speeding, rapid entry, and etc at the entrance nose section. At the entrance connector roads, accidents caused by speeding, negligence, over-operation of handle of drivers were main reason of accidents. Discriminant analysis were conducted about geometric elements to distinguish influencing factors for traffic accidents. the lengths and access angles of the entrance connector roads were regarded as to have the high relation with traffic accidents. RESULTS: After classifying the design section of resting areas' entry as well as derive design elements on each section, a speed measurement by targeting entry of rest areas and car behavior surveys were performed, then each element's minimum standard was derived through the analyses. According to the speeds at the starting/end point of entrance connector road, the range of the junction setting angle of the entrance connector road is defined as $12^{\circ}{\sim}17^{\circ}$ and the connector length model was suggested. CONCLUSIONS: Suggest improvement plans for existing rest areas that can be applied realistically. This should be corresponded to the standards of entry and exit of developed rest areas.

• International Journal of Highway Engineering
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• v.14 no.3
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• pp.173-182
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• 2012

Entry and exits of the rest area are sections where designed speed can be rapidly change and also a weak traffic safety section. In addition, two tasks can be performed simultaneously at entry of the rest area, particularly searching for deceleration and parking spaces/parking sides etc. Thus, design criteria is required in order to procure the stability of accessed vehicle. In case of Korea, geometric structure design criteria of entry facilities, such as toll-gate, interchange, junction etc was established. However there are no presence in a detailed standards for geometric structure of the rest area which affiliated road facilities. In this study, Derive problems in regards to the entry of geometric structure of resting areas by utilizing a sight survey and an investigation research of traffic accidents. The survey was targeting 135 general service areas. After Classifying the design section of resting areas' entry as well as derive design elements on each section, a speed measurement by targeting entry of rest areas and car behavior surveys were performed, then each element's minimum standard was derived through the analyses. According to the speeds at the starting/end point of entrance connector road, the minimum length of the entrance connector road is decided as 40m using Slowing-down length formula and based on the driving pattern, the range of the junction setting angle of the entrance connector road is defined as $12^{\circ}{\sim}17^{\circ}$. Suggest improvement plans for existing rest areas that can be applied realistically. This should be corresponded to the standards of entry and exit of developed rest areas.

• Journal of Korean Society on Water Environment
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• v.33 no.6
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• pp.617-625
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• 2017

Both domestic and overseas urban drainage systems have been actively researched to solve the problems of urban flash floods and the flood damage that is caused by local downpours. Recent urban planning has been designed to better manage the floods of decentralized rainfall-management systems, and the installation of green infrastructure and low-impact development (LID) facilities at national ministries has been recommended. In this study, we use the EPA SWMM model to construct a decentralized rainfall-management network for each small watershed, and we analyze the effect of the drainage-capacity improvement from the installation of the LID technologies in vulnerable areas that replaces the network-expansion process. In the design of the existing urban piping systems, it is common to increase the pipe size due to the increment of the impervious area, the steep terrain, and the sensitive entrance-ramp junction; however, the installation of green infrastructure and LID facilities will be sufficient for the construction of a safe urban drainage system. The applications of LID facilities and green infrastructure in urban areas can positively affect the recovery of the corresponding water cycles to a healthy standard, and it is expected that further research will occur in the future.