PURPOSES : This study aims to analyze and summarize test results related to permeable blocks used for sidewalks and roadways as an alternative to conventional urban road pavement technology, specifically focusing on low-impact development (LID) techniques. Furthermore, it aims to provide reference data on the feasibility of current policy implementation and future policy directions through a longterm analysis of the performance and durability of permeable blocks in sidewalk and roadway construction. METHODS : The research methodology involves (1) conducting a survey on the status and actual conditions of permeability sustainability tests based on the results of permeability persistence tests conducted in Seoul over nine years, from 2013 to 2021; (2) analyzing the differences between the permeability block rating system of Seoul City and that employed by the Ministry of Environment; (3) analyzing the permeability of graded pavement sections in permeable blocks for sidewalks after three years of public use and deriving a regression analysis formula to estimate the maintenance period; (4) analyzing the permeability of pavement sections in permeable blocks for roadways after five years of public use and deriving a regression analysis formula to estimate the maintenance period. RESULTS : This study revealed significant improvements in the performance and quality control of permeable blocks since the implementation of the permeability sustainability test in Seoul in 2013. An analysis of the differences in the permeability coefficient and distribution based on the rating systems of Seoul City and the Ministry of Environment showed that rating system of Seoul City has approximately twice the permeability coefficient quality standard compared to that of the Ministry of Environment. Regression analysis indicated that the firstgrade permeable block was predicted to maintain its permeability for approximately 5.1 years, whereas the third-grade permeable block was predicted to maintain its permeability for approximately 3.1 years. In roadway-permeable block pavements, the first-grade sections maintained excellent quality conditions even after five years, and regression analysis predicted a permeability maintenance period ranging from eight to 17 years. CONCLUSIONS : The correlation analysis of the permeability coefficients based on the common usage period of permeable blocks for sidewalks and roadways presented in this study can provide more accurate estimations of commonality. However, further research under various environmental conditions is required to supplement these findings. Considering the lack of studies on permeable block commonality analysis in Korea, this study highlights the significance of conducting long-term experimental follow-up research to establish commonality prediction formulas for different usage scenarios.

PURPOSES: This study analyzes feasibility for application white pavement markings in the roadways with median barrier. METHODS : By reviewing numerous relevant laws, standards, and operational cases, the white pavement markings' excellence was demonstrated. Driver’s behavior was analyzed through a virtual driving experiment using driving simulator and field tests. RESULTS: First, white pavement markings are superior to yellow pavement markings in terms of visibility, economics, and safety. Second, as a result of virtual driving experiment, the color of line in the roadway with median barrier didn’t affect the driver’s behavior such as the average vehicle speed, the distance bias in the lane and the separation distance from the centerline. Third, field test demonstrated that the driver tended to recognize the median barrier as an obstacle. In addition, the central driving ratio in the lane was increased due to improving the visibility of line at night in case of the white pavement markings. CONCLUSIONS : The application of white pavement markings in the roadways with median barrier can enhance traffic safety by improving the visibility of line at night.

PURPOSES : This paper presents a description of the current issues facing road managers regarding the surface-type conversion of lowvolume roads for cost savings. METHODS: The paper reviews previous works conducted toward this end, acknowledges gaps in the current research, and lays out what information is needed for further studies. RESULTS : If the cost to maintain an unsurfaced road is less than the cost of maintaining a surfaced road, then there is potential for cost savings for the management agency. However, the problem is bigger than simply maintaining the roads that already exist. If unsurfaced roads prove to be more economical than surfaced roads, then the cost to convert from a surfaced to an unsurfaced roadway, and vice versa, when necessary, must also be examined. CONCLUSIONS : No other studies have addressed the un-surfacing of a road for cost savings, and it is therefore unknown whether substantial savings can be realistically obtained by converting from a surfaced to an unsurfaced road. To determine whether a conversion policy would be a viable option, additional data and research are needed.

PURPOSES: The sensitivity of CO2 emissions per vehicle by a various speeds is compared according to the type of roads. METHODS: The methodology of the study are as follows: First, the sensitivity of CO2 emissions per vehicle are analyzed by averaged daily travel speeds. Second, the sensitivity of CO2 emissions per vehicle are analyzed by averaged hourly travel speed. Third, the sensitivity of CO2 emissions per vehicle are analyzed by sectional travel speeds. RESULTS: The sensitivity that on Saturday in a week, at peak times in a day and in close location from Seoul was higher than in other situations. CONCLUSIONS: From this study, we may conclude that CO2 emissions per vehicle at low speeds are generally more sensitive.

PURPOSES: In this study the influence factors related to abrasion resistance of interlocking concrete block have been evaluated, and comparisons between various domestic and foreign abrasion test methods was also accomplished. METHODS: The modified rotational cutting method suggested in ASTM C 944 was applied. Surface materials with different types of fine aggregate such as crushed sand, sea sand, and mixture of crushed and sea sand were tested to compare the aggregate effect for abrasion resistance. RESULTS: The different surface mixtures with various W/C ratios, mortar and fly ash ratios have been investigated for functional and economical considerations. CONCLUSIONS: This study had obtained reliable results by changing diamond blade of rotating cutter. Therefore, in order to improve the abrasion resistance of interlocking concrete block for road, a new mix design was proposed.

The uniformity of lighting distribution on the roadway is essential factor for drivers and pedestrians's safety during nighttime in urban streets. Also, the importance of roadside trees is one of the growing concern for better citizens' health and mitigating environmental impact on the urban street. But roadway lightings and roadside trees have different design or planting standards and they are not integrated in the systemic viewpoint for better safety of users during nighttime. The purpose of this study is to propose a simulation approach which assesses lighting quality in the view of illumination uniformity distribution of roadway lighting from design step and consider the layout of roadside trees. For improving lighting quality of roadway, simulation approach is needed for assessing the impact of diverse planting situation of trees and encouraged from beginning of design step for roadway construction.

Present study was designed to characterize the concentrations of major roadside air pollutants in Daegu and to compare with those of Seoul and Busan. Evaluated were the exceedance frequence of mean concentrations of target compounds(CO, NO2, O3, PM10, SO2) and the relationship for time variation. Two air pollution monitoring stations(one roadside station and one residential station) in Daegu were selected for this study. In addition, one roadside monitoring station from each of Seoul and Busan was chosen for the comparison of Daegu monitoring stations. The data analyzed in the current study were collected from 1998 to 2000 by Daegu Regional Environmental Management Office. The roadside concentrations of NO2 and PM10 and the exceedance frequency of ambient air standard levels in Daegu were higher than those of Seoul and Busan. Except O3, the roadside concentrations of all target compounds showed following three distinguished patterns; first, possibly due to increased traffic density, the concentrations increased from 0500 to 0900(LST), second, the concentrations decreased from 0900 to 1700(LST) possibly due to the increased wind velocity and decreased traffic density, and finally, increased traffic density, the concentrations increased again from 1700 to 2100(LST). An implication was that major air pollution sources shifted from residential area to road-area during rush hours.