PURPOSES : The purpose of this study is to analyze the impact of the level of the light-environment and the driver's visual ability on the change in the driver's perception of a forward curved section at night. The study also aims to identify factors that should be considered to ensure safety while entering curved sections of a road at night. METHODS : Data collected from a virtual driving experiment, conducted by the Korean Institute of Construction Technology (2017), were used. Logistic regression was applied to analyze the effects of changes in the light-environment factors (road surface luminance and glare) and the driver’s visual ability on a driver's perception of the road. Additionally, analysis of the moderated effect of visual ability on light-environment factors indicated that the difference in drivers’ visual abilities impact the influence of light-environment factors on their perception. A driver's ability to perceive, as a response variable, was categorized into 'failure' and 'success' by comparing the perceived distance and minimum reaction sight distance. Covariates were also defined. Road surface luminance levels were categorized into 'unlit road surface luminance' (luminance ≤ 0.1 nt) and 'lit road surface luminance' (luminance > 0.1 nt), based on 0.1 nt, which is the typical level observed on unlit roads. The glare level was categorized as 'with glare' and 'without glare' based on whether the glare was from a high-beam caused by an oncoming vehicle or not. The driver's visual ability level was categorized into 'low visual ability' (age ≥ 50) and 'high visual ability' (age ≤ 49), considering that after the age of 50, the drive’s visual ability sharply declines. RESULTS : The level of road surface luminance, glare, and driver's visual ability were analyzed to be significant factors that impact the driver's ability to perceive curved road sections at night. A driver's perception was found to reduce when the road surface luminance is very low, owing to the lack of road lighting ('unlit road luminance'), when glare is caused by oncoming vehicles ('with glare'), and if the driver's visual ability level is low owing to an older age ('low visual ability'). The driver's ability to perceive a curved section is most affected by the road surface luminance level. The effect is reduced in the order of glare occurrence and the driver's visual ability level. The visual ability was analyzed as a factor that impacts the intensity of the effect of change of the light-environment on the change of the driver's ability to perceive the road. The ability to perceive a curved section deteriorates significantly in 'low visual ability' drivers, aged 50 and above, compared to drivers with 'high visual ability,' under the age of 49, when the light-environment conditions are adverse with regard to the driver’s perception (road surface luminance: 'lit road surface luminance'→'unlit road surface luminance,' glare: 'without glare'→'with glare'). CONCLUSIONS : Supplementation, in terms of road lighting standards that can lead to improvements in the level of light-environment, should be considered first, rather than the implementation of restrictions on the right of movement, such as restricting the passage of low visual ability or aging drivers who are disadvantageous in terms of gaining good perception of the road at night. When establishing alternatives so that safety on roads at night is improved, it is necessary to consider improving drivers' perception by expanding road lighting installation. The road lighting criteria should be modified such that the glare caused by oncoming traffic, which is an influential factor in the linear change in perception, and the level of light-environment thereof are improved.

PURPOSES : Although numerous researches have been studied to reveal accident causations for road intersections, there are still many research gaps for road segments. It is mainly because of difficulty of data and lack of analytical method. This study aims to study accident causations for rural road segments and develop accident modification factors for safety evaluation. The accident modification factors can be used to improve road safety. METHODS : Methods for developing AMF are diverse. This study developed AMFs using accident prediction models and selected explanatory variables from the accident models. In order to select final AMFs, three different methods were applied in the study. RESULTS: As a result of the study, many AMFs such as horizontal curves or vertical curves were developed and explained the meanings of the results. CONCLUSIONS : This study introduced meaningful methods for developing significant AMFs and also showed several AMFs. It is expected that traffic or road engineers will be able to use the AMFs to improve road segment safety.

화학적 첨가제를 이용한 안정처리는 지반의 강도증가 및 변형발생을 제어하기 위한 방법으로 깊은 심도까지 광범위하게 적용되어 지고 있다. 화학적 안정처리의 기본목적은 지반의 강도증가, 압축성 감소, 팽창특성 등을 개선하여 지반의 내구성을 증가시키는 것이며, 최근 들어 환경친화적이며 혼합체의 특성 및 혼합속도를 효율적으로 개선한 다양한 형태의 진보적인 시멘트 혼화재가 개발되고 있다. 본 연구에서는 농어촌도로(농도)의 효율적인 포장공법 개발을 위하여 시멘트혼화재를 활용하는 방안을 연구하였으며, 혼화재 종류 및 배합비에 따른 다짐시험, 일축압축강도시험, 동결융해시험 및 휨강도시험을 실시하였다. 본 연구결과에 따르면, 실트질 원지반토가 점토지반에 비해 강도증가 및 동결융해특성이 우수하며, 액상형 시멘트 혼화재가 분말형태 보다 효과적인 것으로 나타났다. 또한 저배합에서도 고강도의 품질을 발휘하여 농어촌도로 표층 내구성 저하를 개선할 수 있을 것으로 판단된다.

This study is to estimate the circuity factors which can be used to assess for public facilities accessibility and analyze traffic in the area. We set the range of the administrative districts by Si‧Gun‧Gu unit and Eup‧Myeon‧Dong unit (more subdivided unit than Si‧Gun‧Gu unit). The average circuity factor in Si‧Gun‧Gu unit is 1.364 (maximum 2.953 and minimum 1.711). The region indicated the highest value of circuity factor is wando-gun in jeollanam-do, which area consists of 4 island and is connected to the bridges. Having to use the bridges for using public facilities hinders its accessibility. In the case of Eup ‧ Myeon ‧ Dong unit, the average circuity factor is 1.353 (maximum 2.950 and minimum 1.154). The region indicated the highest value of circuity factor is buksan-myeon in chuncheon-si, Gangwon-do. This region also has to use bridges for using public facilities because there is the largest lake, called Soyangho. This circuity factor is used to analyze the location of public facilities and assess vulnerability of accessibility. And also the factor can be applied to some policies, such as rural public service planning based on spatial big data.

This study carried out evaluation of vulnerability in accessability and functionality using road network that was extracted from Intelligent Transportation System(ITS) and digital map. It was built in order to figure out accessability that locational data which include community center, public facilities, medical facilities and highway IC. The method for grasping functionality are Digital Elevation Model(DEM) and land slide hazard map provided by Korea Forest Service. The evaluation criteria for figure out accessability was set to related comparison of average time in urban area. Functionality value was calculated by the possibility of backing the vehicle possibility of snowfall and landslides. At last, this research computed weighting value through Analytic Hierarchy Process (AHP), calculated a vulnerable score. As the result, the accessability of rural village came out that would spend more time by 1.4 to 3.2 times in comparison with urban area. Even though, vulnerability of the road by a snowfall was estimated that more than 50% satisfies the first class, however, it show up that the road were still vulnerable due snowing because over the 14% of the road being evaluated the fifth class. The functionality has been satisfied most of the road, however, It was vulnerable around Lake Daechung and Piban-ryung, Yumti-jae, Suriti-jae where on the way Boeun. Also, the fifth class road are about 35 km away from the city hall on distance, take an hour to an hour and a half. The fourth class road are about 25 km away from the city hall on distance, take 25 min to an hour. The other class of the road take in 30 min from the city hall or aren't affected of weather and have been analyzed that a density of road is high. In A result that compare between distribution and a housing density came out different the southern and the eastern area, so this result could be suggested quantitative data for possibility of development.

Since 2010, RDA has discovered 30 Green-Road as the way of developing rural area. However, results from conference with expert and village leaders of Green-Road concluded that there were problems such as little financial benefits due to mismanagement and needs of improving the efficiency of management. In order to respond to these issues, this research has conducted empirical investigation about the status, management of Green-Road and its influences on local area. Main purposes of this investigation was to reveal the various obstacles in road management, and to find better ways of road management. To accomplish the goal of research, this study conducted survey and interviews with leaders in villages. Particularly, the investigation had focused on the specific management issues suggested by village leaders. Based on the results, this research suggested establishing a committee for creating leaders network and developing effective management method in order to improve road management and its consequences.

The purpose of this study is to develop a simulation model of rural road path for infrastructure of green-tourism and public service in rural areas. This study makes an objective function for moving cost minimization considering car travel time according to road characteristics, which can route the optimal shortest road paths between the center places and all rear villages, based on GIS coverages of road-village network for connecting between center places and rural villages as input data of the model. In order to verify the model algorithm, a homogeneous hexagonal network, assuming distribution of villages with same population density and equal distance between neighborhood villages on a level plane area, was tested to simulate the optimal paths between the selected center nodes and the other rear nodes, so that the test showed reasonable shortest paths and road intensity defined in this study. The model was also applied to the actual rural area, Ucheon-myun, which is located on Hoengsung-gun, Kangwon-do, with 72 rural villages, a center village (Uhang, 1st center place) in the area, a county conte. (Hoengsung-eup, 2nd center place), and a city (Wonju, 3rd center place), as upper settlement system. The three kinds of conte. place, Uhang, Hoengsung-eup, and Wonju, were considered as center places of three scenarios to simulate the optimal shortest paths between the centers and rural villages, respectively. The simulation results on the road-village network with road information about pavement and width of road show that several spans having high intensity of road are more important that the others, while some road spans have low intensity of road.

Since legislation of Rural Minor Road Improvement Act 1990, a quarter of its total length had been paved now. However, over 80% of arterial road length(national+provincial roads) had been paved, so, road improvement policy should be focussed on the local road(county+rural minor roads) from now. Generally, in the greater part of coastal plain and island areas, arterial road intensity(total road length/total catchment area) is relatively low, but local road intensity is relatively high. So, in terms of balanced development, much more efforts for rural minor road improvement should be concentrated in coastal plain and islands areas. In Chonnam Province, the maximum differentials of minor rural road improvement ratio was over 20%(the lowest; 14.1% in Goheung, the highest; 35.6% in Goksung) in 1999, but the improvement budget have been allocated in proportion to unpaved road length of each county by the provincial government. However, the differentials should not be fairly narrowed in the near future if the present budget allocation policy be maintained. To solve this problem, target differentials of rural minor road improvement between regions should be set up for each planning year and road improvement budget be allocated according to this policy change.