PURPOSES : The effect of yellow carpet visibility enhancement was verified and its impact on traffic safety for effective introduction of traffic safety facilities was studied. METHODS : There is currently no scientific evidence demonstrating that yellow carpets improve pedestrian awareness. In this study, the effect of increasing visibility caused by the installation of yellow carpet was verified, and the effect of improving the level of traffic safety was examined through an objective analysis. A drone was used to collect and analyze video data to compare the driving speeds of vehicles passing near yellow carpets at six different sites and diagnose the effects of speed reduction. RESULTS : The results showed that the visibility improvement values before and after the installation of the yellow carpet differed from place to place, but a visibility improvement effect existed in certain cases. In terms of the adequacy of the installation site, the yellow carpet had no deceleration effect on vehicles driving on signalized local streets and collector highways. It was found that there was a speed reduction effect on unsignalized local streets. CONCLUSIONS : To enhance traffic safety promotion, yellow carpets should be placed on unsignalized local streets. It is important to place the yellow carpet in the right place in a proper manner.

PURPOSES : Speed management is essential for enhancing children’s safety in school zones. The objectives of this study are to analyze how digital-based school zone signs and newly proposed signage for increasing visibility influence speed reductions and how the new system facilitates drivers obeying the speed limits. METHODS : A before/after analysis technique with comparison groups (widely used to evaluate safety effects) was employed. To effectively capture the safety effects of the new system, two significant measures were selected as the measures of effectiveness: the rates of change in space mean speeds and speed limit compliance. RESULTS : With three target sites and three comparison sites, the mean space speeds after installing the new systems were found to be slightly reduced for all target sites (the reduction rates of the space mean speed were found to be 5% for site A, 1% for site B, and 6% for site C). The lack of a constant tendency in speed reduction effects at all sites might be owing to the fact that the speed data collection was conducted before the driver's system adaptation was sufficiently performed. Regarding the speed limit compliance rate, significant increases were observed at two sites (10% for site A and 51% for site C), but site B did not show an increasing effect. The reason for the absence of this effect is that the installation of crosswalks and speed bumps at the target site affected the driver's compliance with the speed limit. CONCLUSIONS : An insufficient amount of evaluation results was obtained for the new guidance system. However, the new guidance system method provides an alternative approach to improving children's safety, i.e., by inducing drivers to actively slow down in school zones.

PURPOSES : Since expressways in South Korea are toll roads, many trumpet type interchanges exist, resulting in the installation of loop ramps very frequently. While the travel speed of the main lane is designed to be 100-110 km/h, the structure of a loop ramp is different and is designed for a minimum speed of 40 km/h. In fact, most of the actual travel speeds measured on the ramp exceed the designated speed, which has been a major problem in traffic safety. In this research, a type of pavement marking speed-reduction treatment called the "Peripheral Transverse Line" is installed on expressway loop ramps in order to study the change of driving speeds after the installation. METHODS : To verify statistically the change, this speed-reduction treatment has been installed on the Chungju interchange and the Yeoju junction. The driving speeds before the installation were compared with driving speeds both one month and five monthsafter the installation. RESULTS : As a result, the reductions of the average driving speeds after the treatment were statistically significant. More specifically, the average driving speeds of the Chungju interchange were reduced by 7.1-7.7 % for its tangent road section, and the speeds decreased by 8.5-9.5 % for its curve section. Similarly, in the Yeoju junction, an average speed reduction of 2.9-4.8 % for its tangent section was measured, along with 3.9% long-term speed reduction for its curve section. CONCLUSIONS : Since the pavement marking speed-reduction treatment has been partially proven to be effective from this research, we expect to expand this treatment and re-confirm the effect from a long-term perspective in the future.

고속도로의 터널구간은 일반구간과는 다른 주행특성(속도, 교통량, 밀도 등)을 가지게 되고 이에 따라 고속도로 일반부에서 터널진입 전과 후에 운전자 행태가 변하는데, 가장 대표적인 예가 속도의 감소 현상이라 할 수 있다. 하지만, 이러한 다양한 요인들 중 현재까지 연구의 진행 추세는 도로의 용량, 속도감소 측면의 정량적인 부분에 초점을 맞춘 연구들 위주로 진행되고 있는 것이 현실이다. 따라서 본 연구에서는 터널의 다양한 여건을 고려할 수 있는 구간을 대상으로 설문조사와 설문결과 분석을 통해서 터널구간 속도감소에 영향을 미치는 정성적 요인들을 알아 보았다. 분석 결과 최근 증가 추세인 장대터널과 관련된 터널 자체의 형상(차로폭, 갓길폭, 터널길이)에 대한 요인이 터널 내부 속도감소에 영향을 미치는 것으로 나타났다. 또한 터널입구 보임여부와 같은 시각적 환경이 속도감소의 영향요인으로 나타났으며 터널 내부의 조명밝기에 따라 속도변화가 나타나는 것을 알 수 있었다. 본 연구결과를 활용하여 고속도로 터널부 설계관련 기술개발 및 서비스개선을 위해 지속적인 투자가 이루어질 것이라 판단된다.

신호교차로 구간의 위험원인에 대해서 사전에 사고예방을 강구한다면 사고건수를 줄이는데 도움이 될 것이다. 특히, 신호교차로에서 기하구조 개선과 같이 많은 예산을 투자하지 않더라도 사고감소효과를 낼 수 있다. PG(Positive Guidance) 기법은 신호교차로에서 도로안전시설물의 개선을 통하여 교통사고를 예방할 수 있다. 본 연구에서는 과속으로 인해서 사고위험성이 높은 신호교차로 1곳을 선정하여 대상지점의 문제점 분석 및 개선방안을 도출하였다. 선정된 구간은 시뮬레이터를 활용하여 대상구간의 현황을 그대로 재현하여 실험하였다. 이를 토대로 PG개선 전 후의 지점별 속도효과가 있는지를 검증하기 위해서 t 검증을 실시하였다. 그 결과, 개선 후에는 운전자가 정보를 충분히 제공받아서 신호교차로 부근에서 속도를 감속하는 것으로 나타났다. 향후 본 연구를 토대로, PG기법을 활용할 수 있는 일부 신호교차로에 대해서 많은 비용을 투자하지 않더라도 저비용으로 교통사고 감소 효과를 거둘 수 있다.

본 연구는 시뮬레이터를 이용하여 속도감속 노면표시 유형별로 감속 효과가 어느 정도인지에 대한 연구를 수행하였다. 이를 위해서 20~70대의 다양한 연령층으로 구성한 41명이 실험에 참여하였다. 구간별 기법에 따른 속도현황을 살펴보면, 노면표시 시작지점 및 곡선시작점에서 Peripheral Transverse Line II의 속도 감속효과가 가장 좋은 것으로 나타났다. 본 연구는 도로이용자의 인간공학적 고려 요소를 바탕으로 운전자 시각특성을 고려한 감속유도기법 개발에 있어서 그 효과를 검증했다는 점에서 의의가 있다. 향후 연구로는 감속유도 노면표시가 장기적으로 운전자에게 효과적인지에 대한 검증이 필요하며, 색의 대비(예 : 흰색 노면표시에 검은색 아스팔트)에 따른 속도감속 효과가 있는지에 대한 연구도 필요하다.

There are many types of reduction drives for industrial uses. However, it is essential to use precision reduction drives for accuracy of position controls on robot systems. Among the precision reduction drives, the cycloid reduction drive is well known for its high performances and widely used in precision industrial field. Cycloid reduction drives are mainly used in manipulators in robot system requiring a characteristic of a high precision control. When we design this cycloid reduction drive, there are many factors that must be considered. First, a geometrical analysis of a tooth shape must be drawn from the basic concept. Secondly, load distribution, stress distribution and sliding velocity on a tooth should be calculated exactly. Finally, a computer software to optimize the design of a cycloid tooth needs developing. In this study, many different kinds of factors concerning the characteristic of a cycloid tooth were researched on the basis of the analysis of load, stress and sliding velocity on a tooth. The computer expert system to design the cycloid reduction drive was developed using a Visual C++ compiler. In conclusion, the most important factors can be obtained easily as the user put the simple input data.

This study, for the development of next generation high speed railway system of a train which has maximum speed over 400km/h, is to develop core generic environmental technologies which are soundproof technology. Also this technology contains the emitting noise performance of high speed operated trains. The ultimate purpose of this study is to develop a new technology of core sound proof system which is more economical and efficient to cope with the noise increased about 7~9dB as the operating speed increased to 400km/h. In view of technology, this study is to the new soundproof shape design, noise absorbing material development, core soundproof facility development, noise reduction method which contains the aerodynamic characteristics of noise, the concrete bed track reflecting noise reduction, the specifications absorbing block of concrete bed and the installation and management of core soundproof system.