Heung-Un Oh

High Performance Glass Beads for Traffic Marking in Wet Weather

The performance of road markings is classified into the visibility at daytime, night time, wet condition and rainy conditions. The objective of this study is to obtain the driving safety of drivers under conditions of unstable weather condition such as the rain. The visibility of road markings is closely related to the preview time and detection distances and the ways to improve road marking materials and increase the dry retroreflectivity and wet retroreflectivity, which are the measures of daytime and nighttime visibility is researched to decrease the traffic accidents. For this purpose, Road marking glass beads with the refraction rate of 1.5 and 2.2 are introduced to raise the retroreflectivity. After investigating the minimum threshold retroreflectivity and Install Minimum retroreflectivity at home and abroad, minimum control values for the roadmarking visibility and improvement of nightime rainy retroreflectivity are suggested by physical properties and retroreflectivity experiments.

Abrasion-Resistant Road Markings for Improved Durability Lane to Wear Simulators Test

There is the uncertain period of the construction in case of the products meeting the quality standard of KS M 6080, the quality is degraded because of the abrasive loss of the paint caused by vehicle tires as the traffic amount increases and of the loss and detachment of the glass beads providing the retroreflective function. The abrupt degradation of visibility causes the high frequency of traffic accidents at night and increases the traffic accident rate. Additional supplementary construction induces the direct material and construction costs. As the more cost induction effect than the direct cost, the traffic jam caused by the additional construction increases the indirect social costs such as time cost and vehicle cost. Hence, the study is concerned with performing the abrasion resistance test based on the EN 1436 standard to check and improve the quality of various road marking materials resulting in improving the durability of road marking materials. However, even though the difference in the durability lifetime of resins(binders) is bibliographically or theoretically clear, there was no difference in the durability lifetime (retroreflectivity aspect) of the road marking paint using these binders. The reason is that the bonding of beads was very insufficient or that the cross density caused by crack or freshness was low. Moreover, the measured wet retroreflectivity was distributed as the Rw3 or higher class in average on the basis of EN 1436 but was very insufficient on the basis of the minimum wet threshold retroreflectivity with 100mcd/() managed overseas.

Factors affecting vehicles’ carbon emission in road networks

ABSTRACT In urban highway networks, some factors may influence the amount of average kilometric vehicle carbon emission (AKVC). Especially in highway networks of a large metropolitan area, the factors could be more diversified. In the present paper, the particular factors in the statistics of the districts in Seoul City that affect the AKVCs were investigated. Individual and combined factors were considered. The individual factors in the present study included the number of intersections, the number of intersections per kilometre, the road portion to the total area, the number of registered vehicles, the number of commuters, the population, the population density, the total land area and the road length. The combined factors considered included the number of intersections per kilometre over the number of registered vehicles, the number of intersections per kilometre over the road portion to the total area, and the road portion to the total area over the number of registered vehicles. Using the stepwise regression, it was demonstrated that the number of intersections per kilometre is the only significant factor affecting the AKVC in the road network of the district. All other factors are regarded as insignificant in affecting the AKVC. Additionally, correlation analysis confirms the result. From the study, as ‘the number of intersections per kilometre’ is the most influencing factor on reduction of vehicle carbon emissions in the road network, it may be implied that the number of intersections should be controlled or reduced in the road network of a city.

Greenhouse Gas Emission Patterns at Intersections by Drivers

PURPOSES: To analyze the specific factors of drivers behaviors that amount of cause the greenhouse gas emissions per vehicle. METHODS: Drivers behaviors at intersections are analyzed on the conditions of acceleration and deceleration. RESULTS : First, it is resulted greenhouse gas emissions per vehicle is produced more at intersections than at the main lines of highway. Second, it is resulted that the average speed, the average acceleration rate and the maximum speed are three major factors to produce greenhouse gas per vehicle in acceleration sections. Third, it is resulted that rapid deceleration 20m before entering intersections is the major factor to produce greenhouse gas per vehicle in deceleration sections. CONCLUSIONS: At intersections, sudden acceleration and deceleration is not good for greenhouse gas emissions. Thus, and the average speed, the average acceleration rate and the maximum speed are the chosen as factors to be controlled for drivers` behavior to reduce vehicles` greenhouse gas at intersections.

Vehicles` CO 2 Emissions by Intersection Types

PURPOSES : The present paper is to compare vehicles` emissions in roundabouts and signalized intersections. METHODS : The present paper uses the SIDRA software with variables of traffic and road conditions. RESULTS : The results of the study are as follows : First, when entering traffic volumes are more than 1600pcph, vehicle`s emissions in roundabouts are lower than those of signalized intersections regardless of the left turn ratio. Second, When entering traffic volumes are more than 2800pcph, vehicles`s emissions in 2-lane approaches are lower than those of 1-lane approaches in signalized intersection. Third, when entering traffic volumes are more than 1600pcph, vehicle`s emissions of CASE B are lowest. (CASE B is the condition with one exclusive left-turn lane and one exclusive straight lane and one shared straight lane with right-turn.) Also, CASE A is the condition that vehicle`s emissions in roundabouts are lower than those of signalized intersections between 1600pcph and 3600pcph. (CASE A is the condition with one exclusive left-turn lane and one shared straight lane with right-turn.) But, when entering traffic volumes are more than 4000pcph, vehicle`s emissions in signalized intersections is lower than those of roundabouts. CONCLUSIONS : It may be concluded that vehicle`s emissions on roundabouts are much lower than those of signalized intersections, especially, when entering traffics volumes are between 1600pcph and 3600pcph in 1-lane or 2-lane approaches.

Analysis of CO 2 Emission Sensitivity in Roadways

PURPOSES: The sensitivity of 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 emissions per vehicle are analyzed by averaged daily travel speeds. Second, the sensitivity of emissions per vehicle are analyzed by averaged hourly travel speed. Third, the sensitivity of 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 emissions per vehicle at low speeds are generally more sensitive.

Categorization of Traffic Type According to Seoul-City Administrative District Using Cluster Analysis

PURPOSES : Traffic situation of Seoul City is different each administrative district. because each administrative district population, average travel speed, etc are different. thus, regionally differentiated policy is necessary. METHODS : In this study, first, it is to implement the cluster analysis using the traffic factor of twenty-five administrative districts in Seoul, categorize it into the cluster and understand the properties. second, related factors of speed were derived. and method to increase the speed was investigated. we choose the eleven traffic factors such as the number of traffic accident cases, total length, speed, the number of cross section, the number of cross section per km, the rate of roads, registered cars, population attending office and school, population density, area. RESULTS : In the results, first, we could categorize the Seoul-City administrative district into three clusters. in order to find Factors associated with speed a simple regression analysis was performed. and the number of intersections per km is closely related to the speed. CONCLUSIONS : Through this study, transportation policies reflecting local traffic-related characteristics are required.

Comparison of Vehicle Carbon Emissions in Expressway and National Highway

There are several differences between freeways and general national roads in terms of structures, conditions and limited speeds. Likewise, the characteristics of emission in these roads differ depending on the road types. For these reasons, it is necessary to compare the two types of roads in terms of emissions. The study was performed targeting Gyeongbu Expressway and National Highway 1. Firstly, the amount of emission each car was compared in the whole sections of the both. Secondly, top 10 sections were picked out, and then emission each section were compared. Lastly, two sections which were with the highest and lowest amount of emission per car, were compared. As results, it were found that there were less amount of emission on freeways. because cars are running on uniform velocity at relatively high speed, and that there were more amount of emission on the national highway. because of frequent intersections and associated congestion. It may be concluded that the amount of emission at the national highway could be reduced if signal coordination and intersection intervals are improved there.

Distribution of Uniform Reliability over AADTs Estimated for a New Highway Route

AADT estimation for a new highway route has been performed depending on complicated procedures with diversified variables. However, regardless of types of estimation procedures and variables, errors between AADTs estimated and observed appear in most AADT estimation. They have been statistically expressed in terms of forecast error in percent (FEIP). The presented study is based on FEIP collection at freeway sections. It is found that by the province, there exist historical patterns of FEIPs, safety margins, and reliabilities of estimation. Based on this finding, this paper provides a way to distribute a uniform reliability of AADT estimation for a new highway route. Uniform reliability distribution over AADTs estimated in serial sections of a highway route is important because a uniform reliability of AADTs at the design level potentially guarantees to sustain a uniform level of service during the operation of a highway in serial sections of a highway route. Through the example study in the paper, it may be concluded that the introduction of the reliability concept and historical patterns of FEIPs may improve the AADT estimation in design of a new highway route over which overestimation or underestimation have prevailed.