The purpose of this study is to compare securing of walking roads’ cross section zones in the walking paths by street by street and city by city. The cities involved with this study are Seoul Metropolitan Area and Tokyo Metropolitan Area. The securing of widths are compared based on zone types such as frontage, pedestrian, and furniture zones. The widths are measured directly through on-site surveys. The widths measured are compared the standards given by the present paper. Among 22 sites, the satisfied sites are counted. In terms of frontage zones in Seoul Metropolitan Area, 17 out of 22 sites are counted as satisfied while in Tokyo Metropolitan Area, 18 out of 22 sites are counted as satisfied. In terms of pedestrian zone, in Seoul Metropolitan Area, 13 out of 22 sites are counted as satisfied while in Tokyo Metropolitan Area, 14 out of 22 sites are counted as satisfied. In terms of furniture zone, in Seoul Metropolitan Area, 14 out of 22 sites are counted as satisfied while in Tokyo Metropolitan Area, 11 out of 22 sites are counted as satisfied. In conclusion, although walking roads’ cross section zones such as frontage, pedestrian, and furniture zones are relatively a new standards in Korea and Japan, many sites are founded being satisfied with the standards. However, the rates of satisfaction differs city by city. Especially the rates of satisfaction in furniture zones in Seoul Metropolitan are somewhat higher while the rates of satisfaction in frontage and pedestrian zones are similar between two cities.
Adverse weather is a big challenge not only for the safety of drivers but the safety of Autonomous Vehicles (AV). The gap between human-driving and AV-driving in terms of adverse-weather-perception can be a new challenge for highway engineers. Solutions minimizing the gap need to be defined. By this, the smart road technologies can be specified and developed. The way how to define and quantify the gap is introduced in this presentation.
In this study, we are developing next-generation traffic signal control system, SMART SIGNAL, which is operated using a traffic big-data. To improve urban’s chronic recurrent congestion, SMART SIGNAL conducts real-time traffic signal control based on travel time data of traffic information systems. This research project started in 2015 and is scheduled to end in 2019. This research project consists of three sub-tasks, which are traffic big-data bank system, signal operation algorithm, and field test for SMART SIGNAL. The traffic big-data bank system includes the travel time and traffic volume data from public and private sector’s traffic information systems. Additionally, this system contains taxi trajectory data, CCTV image and smartphone based traffic data. This big-data system predicts the travel time and traffic volume by intersection movement for real-time signal control. The smart signal operation algorithm of SMART SIGNAL consists three sub-algorithm of PRE-CON, CAERUS, and NIMOS. PRE-CON makes today’s signal timing plan using historical traffic data. CAERUS is traffic responsive signal control algorithm based on predicted travel time. NIMOS is spillback control algorithm for oversaturated condition. In this project, field experiment is planned in 2019 in Seoul.
Chloride-based deicing material is excellent to dissolve ice and snow in economical but they accelerate deterioration of concrete or corrosion steel reinforced concrete. Chlorine ions contained in the chloride-based deicing material currently used act as catalysts for accelerating corrosion when the air-void level is above a concentration level, even if the airvoid retain the proper alkali level. Environment-friendly CMA based deicing material has been difficult to use due to high unit prices in the past, but recently prices have stabilized. As an environment-friendly deicing material agent citric acid, which is a typical organic acid in citrus fruits, plays a role of controlling pH and preventing oxidation. This is effective against reducing steel corrosion and concrete deterioration. In the long term, environment-friendly deicing material is economical considering the damages of structures due to existing chloride-based deicing material. Although environmnet-friendly deicing material has these various advantages, they are inferior in performance to existing chloride-based deicing material. This study suggests proper utilization methods through analyzing the effects of existing chloride-based and environmentfriendly deicing material. Experimental results show that some environment-friendly products a similar level of ice-melting effects of existing chloride, but the effect of chloride-based deicing material is relatively good. This suggests that the performance of ice-melting is inferior only with the use of the environment-friendly deicing material. Therefore, it is necessary to improve deicing methods using with environment-friendly deicing material such as sand and other friction material. Further, it is considered that if the frozen area is predicted in advance and spraying is possible, the environment-friendly deicing material can be used more effectively.
The relationship between asphalt mixture and crack resistance is difficult to predict because it is influenced by aggregate particle size, aggregate and asphalt interface characteristics, rheological properties of asphalt type, asphalt coating thickness, temperature sensitivity and porosity. For this reason, various evaluation methods of crack resistance have been developed. In Korea, indirect tensile strength and toughness are used as criteria for crack resistance test of asphalt mixture. DC (T), SCB, Fenix test, and OT (overlay test) have been developed and used internationally as crack resistance test methods. In this study, we compared the conventional crack resistance evaluation methods, and developed a direct tensile fatigue test method which was modified with OT method and Fenix method. Crack resistances were evaluated using reclaimed asphalt pavements (RAP) and virgin asphalt mixtures. As a result, direct tensile fatigue test method was evaluated as suitable for evaluation of crack resistance.
Rest area is a space providing opportunities to use a restroom, refuel, reduce fatigue and receive mechanical maintenance services. In Korea, entering rate to rest area from mainline traffic and duration time in rest area are the key variables in the determination of size of rest area. However, there are many controversies because of inconsistency of those variables between rest areas. Moreover, cases that parking space of newly opened rest area are heavily congested which led to an early expansion are also reported frequently. Review on studies related to design variables for the size of rest area shows that they mostly focus on entering rate, the most superficial aspect of driver’s behavior with regression analysis with mainline traffic volume of and geographical condition. Also, studies did not succeed to explain the difference in entering rates of two different rest areas with similar mainline traffic volume. In this research, aggregate methodology has been adopted to overcome prior studies’ limitation. DSRC (Dedicated Short Rage Communication) data collected from RSE (Road Side Equipment) along expressway has been analyzed to construct trip trajectory of each vehicle. From the analysis of each vehicle’s trip trajectory, rest area usage pattern has been found out to be a result of each vehicle’s travel characteristics including departure time, time of the day when passing rest area, and driving duration. And as a result, data-driven analysis methodology was able to be laid out.
The highway junctions are the areas where frequent congestion occurs due to a conflict between vehicles entering the main road from the connecting road and vehicles passing through the main road, which is the main target of microscopic and macroscopic traffic flow study. The importance of study on the behavior and the interaction between vehicles at the highway junctions has been emphasized as an essential element of the Cooperation Intelligent Transport System (C-ITS) and Autonomous Vehicle technology. In this study, merging location and time of vehicles in acceleration lane of highway merging area is recorded by aerial videos from drones, and vectormodelling method was developed with merging location (y-axis) and merging time (x-axis). In the vector model, the vector region of the traffic flow is represented by the realistic expressible vector region and the stable entry into the highway. The model is compared with the traffic conditions according to speed, traffic volume, and density in main line and connecting road. This study can be used as a basic data for understanding the behavior of vehicles at the highway junctions and It is expected to be used as an operational indicator for advanced transportation such as lamp metering, C-ITS, and Autonomous Vehicle technology to stable traffic flow on the highway.
This study was conducted to develop a heat interception permeability aggregate pavement material that resists increase of air temperature and has permeability by decreasing pavement temperature of city in summer. For this study, a heat interception polymer binder mixed with heat interception material and polyurethane binder. And the study made heat interception permeability aggregate pavement material by mixing heat interception polymer binder. Using the materials, the study conducted flexural strength test and temperature reduction effect experiment. As the result, flexural strength was 5.43MPa average and the temperature reduction effect was effective up to maximum 16 degrees Celsius compared to current asphalt concrete.
Piezoelectric harvester for road power generation was installed on test roads owned by Korea Highway Corporation. 24 harvesters were installed on the concrete pavement and the remaining 12 harvesters were installed on the asphalt pavement. After installation, power generation performance and environmental tests were carried out with three types of vehicles: compact / passenger cars / trucks. The running speed of the vehicle was 30 km/h, 60km/h, 90 km/h. The test results show that the larger the weight of the vehicle, the higher the power generation, the concrete road than the asphalt road, and the exposed type rather than the buried type. The generation amount according to the depth of buried was at least 2.2 times at the depth of 1cm than 5cm depth. When the delegator lighting test was performed using 12 harvesters, it was possible to light up more than 20 seconds in one vehicle due to the improvement of the charging circuit. In addition, the wireless communication module driving test enabled temperature sensing and data transmission for 25 seconds. In addition, there was no breakage of the pavement when driving more than 180 times, and the generation amount was maintained more than 90%. However, Test for the durability of the pavement and the self-durability of the harvester is required more than 180 times of vehicle driving conditions and required more than minimum of 6-12 months of long-term monitoring.
The worldwide PMA pavement is steadily increasing. Unlike straight asphalt at the specified temperature of the performance grade, PMA has little increase in complex modulus after RFTO. Even after satisfying the complex modulus of the original binder, the complex modulus after the RTFO does not satisfy the grade, so that the SBS may be over-prescribed. Unlike straight asphalt, PMA investigated the reason that the complex modulus did not increase after RTFO in this study. SBS consists of a styrene domain and a butadiene matrix. The morphology of SBS in PMA is not clear. The PMA was heat - treated to induce the formation of styrene domain and PG evaluation was carried out. As a result, we confirmed that the formation of styrene domain with aging effect changed the complex modulus after RTFO.