• Korean Journal of Geomatics
• /
• v.3 no.1
• /
• pp.67-72
• /
• 2003

We have seen rapid changes in road systems and networks in urban areas due to fast urbanization and increased traffic demands. As a result, many researchers have put greater importance on extraction, correction and updating of information about road systems. Also, by using the various data on road systems and its condition, we can manage our road more efficiently and economically. Furthermore, such information can be used as input for digital map and GIS analysis. In this research, we used a high resolution aerial photo of the roads in Seongnam area. First, we applied the top-hat filter to the area of interest so that the road markings could be extracted in an efficient manner. The lane separation lines were selected, considering the shape similarity between the selected lane separation line and reference data. Next, we extracted the roads in the urban area using the aforementioned road marking. Using this technique, we could easily extract roads in urban area in semi-automatic way.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.30 no.5D
• /
• pp.505-512
• /
• 2010

Generally, the repeated traffic loading condition should be considered to predict the long-term deformation on road foundations or foundation systems. However, it is not easy to estimate long-term deformation on multi-layered system like roads and railways. For more quantitative analysis, mechanistic-empirical approach requires proper analytical tool, material's model, and material properties of foundation geomaterials under both traffic and environmental loadings. In this study, therefore, laboratory data from the long-term repeated load triaxial tests were used to predict accumulated deformation on pavement foundations and the results were analyzed based on the nonlinear models and stress state considered. All these results are presented and verified on laboratory based scale using the finite element analysis with the deformation characteristics of foundation geomaterials at various stress states.

• International Journal of Highway Engineering
• /
• v.15 no.5
• /
• pp.227-234
• /
• 2013

PURPOSES : In order to do an improving countermeasures for congestion on the highway with a limited budget, it is very important to select a habitual congestion section effectively. This study is develop CSI(Consitency Service Index) which contained the service for drivers on the highway to select a habitual congestion section. METHODS : By applying the concept of service for the users paying a fee, proposed CSI(Consistency Service Index) to determine habitual delay. CSI is mean that users using the highway road must be provided an environment which can driving more than 80kph, anytime, anywhere. RESULTS : The result applying developed method in this study included most of congestion sections selected by conventional method. but, in some section of existing non-congestion section were included by CSI. The annual average speed and CSI correlation analysis result was high correlation. This result proved that CSI was reflecting road traffic condition well. CONCLUSIONS : It was verified practicality from the delay section of gyeonggi-do area highway. we can judge whether or not to be a habitual congestion in the specific highway and do the traffic improving countermeasures accordingly.

• International Journal of Highway Engineering
• /
• v.17 no.6
• /
• pp.97-104
• /
• 2015

PURPOSES : Expressways experience chronic and recurring congestion, especially during weekends and holidays, because of the increased demands for leisure-related travel. The alternatives to solve chronic and recurring congestion may be three-fold: (1) physical expansion of expressway capacities, (2) road pricing, and (3) temporal and spatial distribution of traffic demands. Among these, the third alternative may be the most cost-effective method for the Korea Expressway Corporation (KEC) that can be achieved by using the existing ITS infrastructure. METHODS : KEC initiated a pilot study in which the traffic on congested expressways was managed by providing traffic condition information (i.e., travel times) of neighboring national highways for taking detours via variable message signs (VMS). This study aimed to estimate the detour rate, and the two pilot studies on Seohaean and Yeongdong expressways yielded many benefits. RESULTS : It was revealed that the total length of congestion segments decreased by 7.8 km, and the average travel speed increased by 5.3 km/h. CONCLUSIONS : Based on these findings, it was concluded that the propagation of detour information via VMSs during congestion hours can help reduce congestion on expressways and increase the benefits of the entire network.

• International Journal of Highway Engineering
• /
• v.12 no.2
• /
• pp.9-16
• /
• 2010

Roughness is the most important factor to maintain the road performance, and affects greatly on the design life in Jointed Plain Concrete pavements. Also, the factors the evaluate pavement‘s commonality is the three method such as functionality, safety and structural performance. In evaluating function of road, representative factors is the roughness, which has been used to determine maintenance time as key standard. As research for roughness is absence in pavement design. Applied roughness-model had a low-reliability in Korea. Therefore, it is needed to develop reliable model in road roughness. In this research, uniform specific is applied to distribute them after selecting the concrete pavements. Concrete pavement is divided by sections of 238. Total length of this sections has 281km and account for 16% of total road length in korean concrete pavements for selected sections. Considering the korean roughness-model, the evaluation of roughness is performed for the freezing index, average annual rainfall, condition for the base, the amount of traffic as well as spalling(%), cracking(%), age(year) at the selected section at the selected section. Also, additional sections is selected to evaluate various age which affects on the roughness. As a result of the analysis, it showed that spalling(%), cracking(%), age(year), and the condition of the base affected road roughness. When the correlation with the road roughness was analyzed, the reliable model for road roughness was proposed, and the ratio that can explain road roughness was R2-68.8% and P value-0 which is statistically meaningful.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.10 no.5
• /
• pp.1-13
• /
• 2011

Recently, a number of OBU(On Board Unit) have being spreaded since ETCS(Electronic Toll Collection System)using DSRC(Dedicated Short Range Communication) was installed in the tollgate of the whole country. Many R&D and commercialization related to ITS service using DSRC and OBU mentioned above are ongoing such as traffic information collection and provision and a signal control, and public traffic information and management and so on. Especially, there are many researches conducted(conducting) on traffic information collection and provision using communication between OBU and RSE. However, Standards for both DSRC application and traffic collection and provision are not established clearly yet. So we would like to suggest a method of traffic information collection and provision without changing of standard related to DSRC. This method is to put the traffic messages into the existing Action primitive for ETC, which is described on "Technical criterion IV of basic traffic information exchange" which was notified by Ministry of Land, Transport and Maritime Affairs. Proposed standard application method is applied both to RSE and OBE. It is the same system which ETCS used in highway, currently. We confirmed the efficiency and performance of the system through conducting a variety of driving test using 4 vehicles in real road condition. Result of the real road test shows the effectiveness and validity of this method with about 97% communication success rate and based on studying the cases of 3% communication failure, we can analyse the expected problems in traffic information collection and provision using this method.

• Journal of the Korean Society of Safety
• /
• v.24 no.5
• /
• pp.101-112
• /
• 2009

Recently, with the existing speed-management by law enforcements and physical speed-reduction facilities, the country newly adopted Driver Feedback Sign (DFS) system, which displays driving speed in order to guide the driver to an advisable driving condition. DFS is mainly used in school zones due to reasons related to the ITS. Accordingly, because it is predictable that DFS will result in speed-reduction without legal forces and would have an effect on physical speed-reduction facilities, intersection, crosswalks, and road-alignments, this study will try to verify the efficiency of DFS by researching the vehicle speed in national highways and school zones, which have similar conditions to the urban arterial road. In consequence, on national highways, the drivers had a tendency to travel according to the road-environment such as urban arterial road and not reduce speed voluntarily. In school zones, drivers tend to reduce speed in mornings and afternoons when children travel to school or home, showing that the resulting effect is different according to the road-environment where DFS is installed, and the time slot of the DFS.

• International Journal of Highway Engineering
• /
• v.19 no.5
• /
• pp.1-11
• /
• 2017

PURPOSES : This study is aimed at development of a stochastic pavement deterioration forecasting model using National Highway Pavement Condition Index (NHPCI) to support infrastructure asset management. Using this model, the deterioration process regarding life expectancy, deterioration speed change, and reliability were estimated. METHODS : Eight years of Long-Term Pavement Performance (LTPP) data fused with traffic loads (Equivalent Single Axle Loads; ESAL) and structural capacity (Structural Number of Pavement; SNP) were used for the deterioration modeling. As an ideal stochastic model for asset management, Bayesian Markov multi-state exponential hazard model was introduced. RESULTS:The interval of NHPCI was empirically distributed from 8 to 2, and the estimation functions of individual condition indices (crack, rutting, and IRI) in conjunction with the NHPCI index were suggested. The derived deterioration curve shows that life expectancies for the preventive maintenance level was 8.34 years. The general life expectancy was 12.77 years and located in the statistical interval of 11.10-15.58 years at a 95.5% reliability level. CONCLUSIONS : This study originates and contributes to suggesting a simple way to develop a pavement deterioration model using the total condition index that considers road user satisfaction. A definition for level of service system and the corresponding life expectancies are useful for building long-term maintenance plan, especially in Life Cycle Cost Analysis (LCCA) work.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.12 no.6
• /
• pp.54-67
• /
• 2013

The main purpose of this study is to analyze the diversion rate by the levels of delay and the types of display. For this study, we developed the logit model by analyzing the result of SP survey of drivers who have driver's licence after manipulating a virtual driving simulator. The result of analysis was that the types of display was not statistically significant to the diversion rate. On the other hand, the levels of delay was very meaningful factor with the diversion rate. When the main road was flowing smoothly, drivers started to detour at the levels of delay 125% under the traffic free flow state. Similarly, when the levels of delay got worse, the diversion rate kept the same percentage as it was at the levels of delay 125% state which represented a smooth road condition. Likewise, when the main road's traffic flow was slow, drivers appeared to make detours at the same state of the levels of delay 125%. It was found that as the levels of delay got worse, the diversion rose higher than the diversion rate at the condition of slow traffic flow situation with the levels of delay 125%. The result of this study suggests the criterion of drivers detour point. For the conclusion, the result of study would be a reasonable reference for establishing transportation strategies by reflecting drivers' detouring property and would improve the efficiency of traffic flow.

• Journal of Korean Society of Transportation
• /
• v.26 no.3
• /
• pp.155-167
• /
• 2008

This paper studies a multiple user class variable demand user equilibrium and system optimal condition, and then establishes solution algorithms for them. The traffic network equilibrium is accomplished with basis on following assumptions. For considering heterogeneous road user, several user classes have discrete set of VOTs and the travel demand of each user classes varies according to generalized travel cost. this paper specifically investigates following question on multi-class variable demand: Are user equilibrium flows pattern dependent on the unit (time or money) perceived by road user classes? What is system optimal condition according to the unit used in measuring the travel cost or disutility? Finally, using this network equilibrium condition, The traffic assignment algorithm of each equilibrium condition are established.