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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Korean Society of Transportation
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Korean Society of Transportation
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Volume & Issues
Volume 20, Issue 7 - Dec 2002
Volume 20, Issue 6 - Dec 2002
Volume 20, Issue 5 - Oct 2002
Volume 20, Issue 4 - Aug 2002
Volume 20, Issue 3 - Jun 2002
Volume 20, Issue 2 - Apr 2002
Volume 20, Issue 1 - Feb 2002
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Accident Reconstruction Analysis by Mathematical and Optimization Method from Skid Mark and Stopped Position
Journal of Korean Society of Transportation, volume 20, issue 4, 2002, Pages 7~17
This research investigates the location and speed at the time of collision for an accident case. The collision location was determined by a mathematical method using the tire skid mark on the road surface. The collision speed is determined by a optimization method that minimizes a objective function of the difference in the location of the final stopped position of the vehicle observed in a real collision and a simulated collision experiment. The analysis of the collision speed using the optimization method with an error tolerance of 0.8% revealed the collision speed to be 67.76km/h for the passenger sedan and 29.67km/h for the Jeep. However, the collision speed analyzed using current collision speed analysis model equation was 64.97km/h for the passenger sedan and 31.27km/h for the Jeep. Therefore, it has been seen that the difference in the collision speed analyzed by the optimization method and current analysis model equation was 2.78km/h for the passenger sedan and 1.6km/h for the jeep. Since the speed difference between mathematical method and simulation technique is minimal. use of simulation technique is recommended to further investigate the dynamic motion of vehicle after collision in addition to speed.
An Experimental Study on Fundamental Characteristics of Bicycle Flows
Journal of Korean Society of Transportation, volume 20, issue 4, 2002, Pages 19~26
The purpose of this paper is to study the fundamental characteristics of bicycle flows. Several experiments were conducted to obtain the characteristics of bicycle flows, speed variation along a curve radius, bicycle driver's travelling territory and saturation flow rate at signalized intersection. Bicycle facilities are categorized into uninterrupted and interrupted, the capacity of uninterrupted is approximately 5000bic/h, and that of the interrupted (at signalized intersection) is approximately 3000bic/h, when a curve radius is over 20m, bicycle speed is not increasing. Bicycle driver's travelling territory is used to occupancy area, it is the same concept as pedestrian's. Bicycle occupancy area is to be divided into circulation zone, comfort zone. and collision zone. Circulation zone is over 2.21
4.1m and collision zone is less than 0.96
2.47m. Comfort zone is defined as intermediate state between two zones.
Disaggregate Demand Forecasting and Estimation of the Optimal Price for VTIS
Journal of Korean Society of Transportation, volume 20, issue 4, 2002, Pages 27~38
VTIS(Value-added Traffic Information System), among the sub-systems of ATIS, is an Advanced Traffic System which innovates efficiency and safety. And this system, having marketability and publicness, is very important. Moreover, This system offers definite traffic information according to the demand of specified users. And it is expected to produce additional spread effects because of high participation rate of private sector. However, the VTIS service media are varied and there are varied optimal Prices and payment methods according to each medium. Because of that, there needs the study on these problems or optimal criteria. But because existing studies were devoted to estimate the optimal route, the study toward the optimal price which was considered part of user and service use demand do not exist. Accordingly, we surveyed under imaginary alternative pricing scenarios and forecasted the use demand of VTIS by using Binary Logit model. Also, for the users who answered that they would use VTIS service in survey, we classified their use's behaviors as four categories and estimated the use ratio to each category by using Ordered Probit model. Last, using sensitivity analysis for results form above, we derived the optimal price that is 2800won in monthly. 145won in payment per call. Then, VTIS service use rate is respectively 65%, 75%.
Valuation of Air Pollution related to Road Traffic in Seoul
Journal of Korean Society of Transportation, volume 20, issue 4, 2002, Pages 39~48
External effects of road traffic become important as transport systems develop and it is increasingly realized that the valuation of the effects should be incorporated in the process of the transport project evaluation. However, in Korea the number of studies on the valuation of the external effects related to road traffic is few and the valuation of the external effects is ignored in the transport project evaluation. In this study, willingness to pay(IVTP) for environmental benefits for reductions in the air pollution of Seoul is investigated using Stated Preference(SP) method. In particular, for the valuation of air pollution related to only road traffic. the contribution of car emissions in the air pollution is considered. It was found that the choice of the residential location was an appropriate experimental context for the valuation of the reduction in air pollution. The valuation of 1% air pollution per household is 2.40million won per year. Furthermore, valuation for one unit reduction of the air pollutants was calculated using the environment monitoring data. The valuation of 0.01ppm of
is 55.40million won per year and 0.01ppm of NO
per household is 18.33million won per year. The results of this study can be used as important inputs for evaluation of transport and environmental appraisal.
Development of a Freeway Travel Time Forecasting Model for Long Distance Section with Due Regard to Time-lag
Journal of Korean Society of Transportation, volume 20, issue 4, 2002, Pages 51~61
In this dissertation, We demonstrated the Travel Time forecasting model in the freeway of multi-section with regard of drives' attitude. Recently, the forecasted travel time that is furnished based on expected travel time data and advanced experiment isn't being able to reflect the time-lag phenomenon specially in case of long distance trip, so drivers don't believe any more forecasted travel time. And that's why the effects of ATIS(Advanced Traveler Information System) are reduced. Therefore, in this dissertation to forecast the travel time of the freeway of multi-section reflecting the time-lag phenomenon & the delay of tollgate, we used traffic volume data & TCS data that are collected by Korea Highway Cooperation. Also keep the data of mixed unusual to applicate real system. The applied model for forecasting is consisted of feed-forward structure which has three input units & two output units and the back-propagation is utilized as studying method. Furthermore, the optimal alternative was chosen through the twelve alternative ideas which is composed of the unit number of hidden-layer & repeating number which affect studying speed & forecasting capability. In order to compare the forecasting capability of developed ANN model. the algorithm which are currently used as an information source for freeway travel time. During the comparison with reference model, MSE, MARE, MAE & T-test were executed, as the result, the model which utilized the artificial neural network performed more superior forecasting capability among the comparison index. Moreover, the calculated through the particularity of data structure which was used in this experiment.
3-Dimensional Balancing Technique for Nationwide Travel Demand Model using Toll Collecting System Data
Journal of Korean Society of Transportation, volume 20, issue 4, 2002, Pages 63~72
We applied 3-D balancing technique to estimate nationwide travel demand using travel behavior of Toll Collecting System data, socio-economic data in the region, and the data of several organizations connected with travel demand estimation. The results from this study were validated by the indices of RMSE(Root Mean Square Error), TLFD(Trip Length Frequency Distribution). TCS based inter-city average travel to measure of reliability and adequacy of estimated travel demand. Finally, 3-D technique seems to reflect more travel behavior of TCS OD than 2-D technique, but we cannot assert that 3-D technique superior to 2-D technique.
Determination of the Required Minimum Spacing between Signalized Intersections and Bus-Bays
Journal of Korean Society of Transportation, volume 20, issue 4, 2002, Pages 73~82
The influence of bus stops near signalized intersections is one of the important factors which cannot be negligible in the analysis of the capacity of signalized intersections. Absence of consideration of bus bay can reduce capacity and increase the time that the stop of buses block other traveling vehicles. This influence is reflected by the bus blockage adjustment factor in KHCM, but the factor does not consider the course of each bus passing the intersection. Particularly, left turn buses have more influence on the capacity than the other buses and require the minimum length of the road for lane changes. All the existing criteria can apply only to arterial roads on which mostly traffic flows are continuous. And the criteria. which can determine the optimum location and the minimum distance between a signalized intersection and a bus bay, is not prepared and the related study is insufficient. Therefore, a theoretical formula is derived in this study being based on the theories which are avaliable to apply to the situation of signalized intersections.
OD matrix estimation using link use proportion sample data as additional information
Journal of Korean Society of Transportation, volume 20, issue 4, 2002, Pages 83~93
To improve the performance of estimation, the research that uses additional information addition to traffic count and target OD with additional survey cost have been studied. The purpose of this paper is to improve the performance of OD estimation by reducing the feasible solutions with cost-efficiently additional information addition to traffic counts and target OD. For this purpose, we Propose the OD estimation method with sample link use proportion as additional information. That is, we obtain the relationship between OD trip and link flow from sample link use proportion that is high reliable information with roadside survey, not from the traffic assignment of target OD. Therefore, this paper proposes OD estimation algorithm in which the conservation of link flow rule under the path-based non-equilibrium traffic assignment concept. Numerical result with test network shows that it is possible to improve the performance of OD estimation where the precision of additional data is low, since sample link use Proportion represented the information showing the relationship between OD trip and link flow. And this method shows the robust performance of estimation where traffic count or OD trip be changed, since this method did not largely affected by the error of target OD and the one of traffic count. In addition to, we also propose that we must set the level of data precision by considering the level of other information precision, because "precision problem between information" is generated when we use additional information like sample link use proportion etc. And we Propose that the method using traffic count as basic information must obtain the link flow to certain level in order to high the applicability of additional information. Finally, we propose that additional information on link have a optimal counting location problem. Expecially by Precision of information side it is possible that optimal survey location problem of sample link use proportion have a much impact on the performance of OD estimation rather than optimal counting location problem of link flow.
Efficiency of Transportation Policies from the General Equilibrium Perspective (The Cases of Congestion Tax and Marginal Cost Pricing)
Journal of Korean Society of Transportation, volume 20, issue 4, 2002, Pages 95~107
Congestion and increasing returns to scale in the use of and in the provision of transportation facilities have been biggest challenges to policy makers. In order to counter these problems and thereby to promote economic efficiency, optimal congestion tax and marginal cost pricing are separately and strongly recommended for each case. In this paper, however, we show that they are valid only in Partial equilibrium context in which only the corresponding market is considered. We set up a formal general equilibrium model and prove that the recommended policies are not in general effective. We continue to give particular examples which show the invalidity of each policy and continue to show that in the same examples, there exist better but unconventional policies. Based on these findings we strongly suggest to employ quantify restricting policy measure or to find second-best pricing policies.
Alignment Optimization Considering Characteristics of Intersections
KIM, Eungcheol ; SON, Bongsoo ; CHANG, Myungsoon ;
Journal of Korean Society of Transportation, volume 20, issue 4, 2002, Pages 109~122
This paper develops modeling processes for highway alignment optimization considering characteristics of intersections using genetic algorithms. Since existing highway alignment optimization models have neglected the characteristics of intersections, they have shown serious weaknesses in real applications. In this paper, intersection costs include earthwork, right-of-way, pavement, accident, delay and fuel consumption costs that are sensitive and dominating to alignments. Also, local optimization of intersections for saving good alignment alternatives is developed and embedded. A highway alignment is described by parametric representation in space and vector manipulation is used to find the coordinates of intersections and other interesting points. The intersection cost estimation model developed in this study has acceptable precision level in estimating intersection costs and eventually enhancing the performance of highway alignment optimization models. Also, the local optimization of intersections can be used for improving search flexibility, thus allowing more effective intersections. It also provides a basis for extending the alignment optimization from single highways to networks. The two artificial examples presented show that total intersection costs are substantial and sensitive to highway alignments.
Design of Maximum Green Time Parameters for Traffic Actuated Operation
KIM, Jin Tae ;
Journal of Korean Society of Transportation, volume 20, issue 4, 2002, Pages 123~134
The design of the maximum green time parameters for traffic-actuated operations has been mainly based on (1) the models proposing the relationship between the pretimed optimal green times and the Parameters and (2) on the engineering judgment within the parameter range that the models suggest. No model is developed based on the mechanics of the traffic-actuated operation, and no model explicitly designs the parameter. The design of the maximum green time Parameter has been the estimation based on the optimal green time designed for pretimed operation. This document describes a computational procedure designing the maximum green time parameters based on (1) the evaluation of the performance of traffic-actuated systems through the mechanics of the traffic-actuated operation and (2) the hybrid Genetic Algorithm(HGA), a combination of Genetic Algorithm(GA) and the hill-climbing method. The Corridor Simulation(CORSEM) program was used to verify the optimal solutions, which are impossible to know from the field test. Through the comparison between the optimal parameter values found from the CORSIM exhaustive searches and the ones from the proposed method, it has been demonstrated that the Proposed method finds the best solution minimizing the overall average control delay when volume-to-capacity(v/c) ratio is less than one. Since the pretimed operation is appropriate when v/c ratio is higher than one, the proposed method is valuable for designing the parameter for traffic-actuated operation.
Rolling Horizon Implementation for Real-Time Operation of Dynamic Traffic Assignment Model
SHIN, Seong Il ; CHOI, Kee Choo ; OH, Young Tae ;
Journal of Korean Society of Transportation, volume 20, issue 4, 2002, Pages 135~150
The basic assumption of analytical Dynamic Traffic Assignment models is that traffic demand and network conditions are known as a priori and unchanging during the whole planning horizon. This assumption may not be realistic in the practical traffic situation because traffic demand and network conditions nay vary from time to time. The rolling horizon implementation recognizes a fact : The Prediction of origin-destination(OD) matrices and network conditions is usually more accurate in a short period of time, while further into the whole horizon there exists a substantial uncertainty. In the rolling horizon implementation, therefore, rather than assuming time-dependent OD matrices and network conditions are known at the beginning of the horizon, it is assumed that the deterministic information of OD and traffic conditions for a short period are possessed, whereas information beyond this short period will not be available until the time rolls forward. This paper introduces rolling horizon implementation to enable a multi-class analytical DTA model to respond operationally to dynamic variations of both traffic demand and network conditions. In the paper, implementation procedure is discussed in detail, and practical solutions for some raised issues of 1) unfinished trips and 2) rerouting strategy of these trips, are proposed. Computational examples and results are presented and analyzed.
Development of The Freeway Operating Time Prediction Model Using Toll Collection System Data
Journal of Korean Society of Transportation, volume 20, issue 4, 2002, Pages 151~162
The object of this study is to develop an operating time prediction model for expressways using toll collection data. A Prediction model based on modular neural network model was developed and tested using real data. Two toll collection system(TCS) data set. Seoul-Suwon section for short range and Seoul-Daejeon section for long range, in Kyongbu expressway line were collected and analyzed. A time series analysis on TCS data indicated that operating times on both ranges are in reasonable prediction ranges. It was also found that prediction for the long section was more complex than that for the short section. However, a long term prediction for the short section turned out to be more difficult than that for the long section because of the higher sensitivity to initial condition. An application of the suggested model produced accurate prediction time. The features of suggested prediction model are in the requirement of minimum (3) input layers and in the ability of stable operating time prediction.
Traffic Accident Prediction Model by Freeway Geometric Types
Journal of Korean Society of Transportation, volume 20, issue 4, 2002, Pages 163~175
Fatalities from traffic accidents constitute one of the major health issues as well as safety ones in Korea. It has been reported that traffic accident is affected by the combined effects of road. vehicle. and human factors. Over the past few decades, a number of studies have been conducted to find the impact of road geometric factors on traffic safety. The purpose of this study is to investigate the effect of road geometric factors on traffic safety on Korean expressways. Detailed geometric design data were available from Korea Highway Corporation. Five-year traffic accident data on Honam expressway were collected and analyzed. It was found that following geometric factors influence traffic safety on expressways : radius of curve, curve length, and length of straight section. Furthermore, the existence of I.C. turned out to have a significant impact on traffic safety level. Based on the data analysis several multiple regression forms that relate traffic accident frequencies and geometric factors on expressways are developed.
A Model Development of Prove Cars for Travel Time Data Collection
Journal of Korean Society of Transportation, volume 20, issue 4, 2002, Pages 177~185
The purpose of this paper is to identify the factors influencing the required number of probe cars and to develop a model for optimal number of probe-cars in beacon-based link travel time data collection system. Various vehicles can be used as probe-cars, such as privately owned automobiles, taxis. buses, etc However, in order to get traffic information of a certain level of accuracy how many probe-cars are required has not been studied in depth. The optimal number of probe-cars will be influenced by many factors such as the technology for collecting link travel time data. the type and operating characteristics of probe-cars, the reliability of the system in collecting data. the accuracy of the collected data, etc. In determining the number of probe cars, three determining criteria are defined. Based on these criteria, models for determining the number of probe cars are developed. In general, the required number of probe cars increases with the average number of travel time data per link
, the minimum number or the density of probe cars on a link at anytime
, the probability of a certain the density of probe cars(
), and the portion of no-data links(
). A case study is performed for a traffic information system in Korea.
The Capacities of Current Facilities and the Policies for the
Phase of Construction in Incheon International Airport
Journal of Korean Society of Transportation, volume 20, issue 4, 2002, Pages 197~212
Analysis of Effectiveness on Improving Hazardous Roads
Journal of Korean Society of Transportation, volume 20, issue 4, 2002, Pages 213~222
Developing Bridge Maintenance Policy Using Life-Cycle Cost Analysis
Journal of Korean Society of Transportation, volume 20, issue 4, 2002, Pages 225~226