This study investigates the impacts of road traffic conditions and driver’s characteristics on the takeover time in automated vehicles using a driving simulator. Automated vehicles are barely expected to maintain their fully automated driving capability at all times based on the current technologies, and the automated vehicle system transfers the vehicle control to a driver when the system can no longer be automatically operated. The takeover time is the duration from when the driver requested the vehicle control transition from the automated vehicle system to when the driver takes full control of the vehicle. This study assumes that the takeover time can vary according to the driver’s characteristics and the road traffic conditions; the assessment is undertaken with various participants having different characteristics in various traffic volume conditions and road geometry conditions. To this end, 25 km of the northbound road section between Osan Interchange and Dongtan Junction on Gyeongbu Expressway in Korea is modeled in the driving simulator; the experiment participants are asked to drive the vehicle and take a response following a certain triggering event in the virtual driving environment. The results showed that the level of service and road curvature do not affect the takeover time itself, but they significantly affect the stabilization time, that is, a duration for a driver to become stable and recover to a normal state. Furthermore, age affected the takeover time, indicating that aged drivers are likely to slowly respond to a certain takeover situation, compared to the younger drivers. With these findings, this study emphasizes the importance of having effective countermeasures and driver interface to monitor drivers in the automated vehicle system; therefore, an early and effective alarm system to alert drivers for the vehicle takeover can secure enough time for stable recovery to manual driving and ultimately to achieve safety during the takeover.

We examined 15,446 single-family detached houses and 2,494 apartment houses in Saha-gu, Busan Metropolitan City, to see whether the accessibility to social overhead capital (living SOC), influences housing prices spatially. Living SOC represents different types of essential facilities. We divided houses into single-family detached houses and apartment houses to perform a more accurate analysis. We used a geographically weighted regression (GWR) model for local-level analysis with a 200-m grid and 400-m grid as spatial units to consider spatial effects. The GWR model explained the price variation better than an ordinary least squares (OLS) model. The results provide a variety of implications to consider when establishing a business-and-action plan based on living SOC.

One of the most important ways to improve pedestrian spaces is to quantitatively analyze the preferences of pedestrians through concrete and empirical data. This requires a psychological evaluation on pedestrians and an analysis on correlations between pedestrian space elements and pedestrians’ preferences. In this study, the relationship between landscape elements in pedestrian space and the preferences of pedestrians was analyzed. The quantitative information of landscape elements was obtained from landscape sequences because pedestrians experience the landscape as a sequence, not individual scenes. The analysis was used to develop a comprehensive index of how pedestrians look at pedestrian spaces. A psychological evaluation was performed to obtain pedestrian preferences for different spaces and the influencing factors. This study clarified the landscape elements preferred by pedestrians, and the results can be used to develop basic guidelines for the planning and design of pedestrian spaces.

Real-time hybrid method is an economical and efficient test method to evaluate the dynamic behavior. The purpose of this study is to develop the computational algorithm and to prove the reliability of a real-time hybrid control system. For performing the multi-direction dynamic test, three dynamic actuators and the optimized real-time hybrid system with new hybrid simulation program (FEAPH) and a simplified inter-communication were optimized. To verify the reliability and applicability of the real-time hybrid control system, 3-DOF (3 Degrees of Freedom) non-linear dynamic tests with physical model were conducted on a steel and concrete frame structure. As a ground acceleration, El Centro and Northridge earthquake waves were applied. As a result, the maximum error of numerical analysis is 13% compared with the result of shaking table test. However, the result of real-time hybrid test shows good agreement with the shaking table test. The real-time hybrid test using FEAPH can make good progress on the total testing time and errors. Therefore, this test method using FEAPH can be effectively and cheaply used to evaluate the dynamic performance of the full-scale structure, instead of shaking table and full-scale test.

Various road occupation works pose potential risks of traffic accidents because they cause traffic bottleneck and congestion, which lead to unstable driving patterns such as quick deceleration and lane changes of vehicles. Even though guidance signs are installed and managed in work zones for preventing traffic accidents, the differences of installation criteria set by the Korea Expressway Corporation (KEC) and the Ministry of Land, Infrastructure and Transport (MOLIT) may increase the confusion of drivers. Therefore, this study set scenarios that take into consideration the colors and shapes of the work zone guidance signs used in driving tests through a virtual driving simulator and a survey on the preferences of drivers. According to the survey on the preference of drivers, 73% of the respondents analyzed prefer guidance signs in fluorescent orange color. In terms of driving patterns, the criteria of the KEC were found to induce smooth deceleration in expressway work zones than those of the MOLIT. In terms of driver concentration, the guidance signs conforming to the criteria of the KEC led to approximately 1.15 times higher concentration than those conforming to the MOLIT, which means that the former induce cautious driving in expressway work zones. The result of this study may be utilized as meaningful data for preventing traffic accidents by improving the traffic safety of road work zones on expressways and general roads, as well as by improving the traffic flow efficiency.

Direct vehicle access at site is usually restricted in situations where the driveway corner clearance (DCC) is designated, as per the District Unit Planning Guidelines. Currently, no clear installation standard for the DCC in Korea exists; thus, vehicles are allowed access regardless of the clearance between the driveway and the intersection. When driveways are located adjacent to the intersection, frequent conflicts between vehicles on minor and major roads occur. This results in problems with traffic communication and safety, necessitating a reasonable design. Therefore, in this study, DCCs were classified into upstream driveway corner clearance (UDCC) and downstream driveway corner clearance (DDCC), and algorithms and scenarios for calculating the appropriate DCC distance were proposed. DDCC was calculated from the traffic volume entering the rightmost lane of the DDCC from among the 12 intersection directions by applying optimized signal phase sequence and car-following theory. The DDCC results demonstrated that at least one vehicle in the driveway can exit to the rightmost lane on the roadway at 9.22 m. Two vehicles can exit at 32.15 m, and three vehicles can exit at 67.54 m. UDCC was calculated by considering its geometry, the traffic volume, queue length, and the 8.45 m additional distance from the driveway. Therefore, as traffic volume increased, the queue length and queue clearance time of the queue increased. The calculated DCC distance proposed in this study can contribute to establishing design standards in the future when establishing guidelines for district unit planning.