PURPOSES : The purpose of this study is to introduce the development of M5 low-level lighting (LLL) with the necessity and justification, mainly the ecological traffic safety merits and the convenience and traffic efficiency of maintenance compared to the existing high mounted pole lightings. The basic photometric property of the developed facility is analyzed. The visual performance is analyzed in terms of visibility distance and subjective opinions from the subjects on several factors related to lighting performance. METHODS : The basic photometric properties of LLL were measured in a tunnel-shaped shield with a visibility meter (LMK 5 Color). The visibility distance between LLL and existing pole-based lighting was observed by 13 subjects under various weather conditions, such as dry, rainy, and wet conditions. In addition, the subjective opinions in terms of several pre-designed factors regarding lighting performance were surveyed. RESULTS : The developed M5 LLL satisfied photometric requirements such as average surface luminance, overall uniformity, and lane uniformity, as suggested by the lighting guidelines. More than 200 m of visibility distances were measured under normal weather conditions for both LLL and existing pole lightings. However, more than 200 m were observed under a wet surface and a rain intensity of 20 mm/h in the case of LLL, but visibility distance was reduced to 48.46 m in the case of pole lightings. A higher visibility distance was observed in the case of amber colored LLL. According to the results of the subjective opinion survey, all types of lightings had favored ratings, and the whitecolored LLL showed the highest ratings under normal weather conditions. However, existing pole lightings had unfavorable ratings under wet surface and rainy conditions, whereas the amber colored LLL had favorable ratings compared to pole lightings in terms of uniformity of illumination, glare, and psychological stability. CONCLUSIONS : The necessity of M5 LLL lies on the cost-effective application to the low standard roadways where the cost is always the main factor to consider in safety facilities and the ecological benefits of roadsides. The developed LLL satisfied the basic optical property suggested by the related lighting guidelines and showed higher performance in terms of visibility distance across various weather conditions compared to the existing high mounted pole lightings.

도로 조명의 등급 설정을 위해 적용된 개념은 Luminance Concept과 Visibility Concept으로 구분이 가능하다. 전자는 노면의 휘도 분포(평균휘도, 균제도 등)를 기준으로 도로 조명의 수준(등급)을 평가하는 개념으로 한국을 비롯한 거의 대부분의 국가에서 CIE의 권고사항을 수정하여 기준으로 활용하고 있다. 후자는 운전자의 장애물 식별 능력과 직접적으로 관련된 장애물과 노면의 휘도대비를 기준으로 도로 조명 의 수준(등급)을 평가하는 개념으로 미국(ANSI) 등 북아메리카 일부 국가 및 유럽에서 적용되고 있다. 본 연구는 Visibility Concept의 개념을 활용한 도로 조명 시인성능 평가 기준 설정을 위한 목적으로 공용전 도로에서 피험자 주행실험을 수행하였다. 실험은 장흥송추우회도로 건설공사(서울지방국토관리 청) 구간 중 직선구간 왕복 2.0km 구간에서 60대 피험자 각 30명을 대상으로 2015년 8월 야간에 수행되 었다. 실험에 활용된 승용 차량의 전면창 투과율은 41.46%이다. 대칭 조명 방식의 가로등을 활용하여 특 정 노면 휘도를 구현하였으며, 다양한 반사율의 종이 박스 및 밝기 조정(디밍)이 가능한 조명 박스를 활용 하여 인위적으로 Positive Contrast(장애물이 노면 보다 밝은) 조건에서의 노면 및 장애물의 휘도 관계를 구현하였다. 노면 휘도(Ls)는 0.3, 0.6, 1.6, 3.0 cd/m2의 4가지 조건으로 구성되었으며, 장애물 휘도(Lo) 는 Positive Contrast 조건이 묘사될 수 있도록 노면 휘도(Ls)와의 관계가 구성되었다. 그림 1은 실험결과로 도출된 60대 피험자의 노면 휘도(Ls)별 장애물 휘도(Lo)와 15백분위 장애물 확인 거리(Dop)의 관계로, 향후 이 결과를 활용하여 Visibility Concept(휘도대비) 기반의 시인성능 기준을 정 립할 계획이다.

PURPOSES: This study aimed to evaluate the appropriateness of safety with the standard for threshold zone luminance as specified in the Recommendation for Lighting of Traffic Tunnel, which has been widely adopted worldwide. METHODS: A driving test of the subject in a full-scale road tunnel was conducted. The adaptation luminance and threshold zone luminance, which should be known for the driver to perceive an object within stopping sight distance, were obtained. These values were compared with the adaptation luminance and threshold zone luminance obtained by the existing reduced model test and tunnel lighting standard that has served as a guideline for the current threshold zone luminance standard. RESULTS : According to this study, threshold zone luminance should be increased to at least 1.8 times the value proposed in the existing studies and to twice the domestic tunnel lighting standard (KS C 3703: 2014). CONCLUSIONS : The threshold zone luminance proposed in this study differs largely from that obtained from indoor tests and from the current tunnel lighting standard used worldwide; this difference may be attributed to the fact that the indoor tests did not incorporate driving workload, non-uniformity of luminance distribution in terms of sight, and factors that reduce the visibility of the driver, such as the light reflected into the driver’s eyes. Hence, it is necessary to further review the factors that reduce the visibility of drivers approaching tunnels in order to determine the rational tunnel threshold zone luminance.

도로의 악영향 및 악천후로 인해 교통사고 유발, 도로변 민원 등이 다수 발생하고 있다. 악영향 및 악 천후 요인별로 보면 기상상태 악화(폭우, 폭설, 안개 등)로 인한 교통사고는 1.4% 증가하였고, 치사율도 약 3배 높은 것으로 분석되었다. 도로교통소음으로 인한 사회적 비용은 연간 34조원(2012년)으로 2005년 대비 44% 증가하였고, 민원 발생 42,000건(2009년 기준)으로 인한 사회적 손실도 증가되고 있는 실정이 나, 실질적인 소음저감 혹은 소음 측정을 위한 정량적 실험시설은 부족한 현실이다. 야간 교통량이 전체 교통량 중 차지하는 비율은 약 30% 정도임에도 불구하고 야간 사고 발생건수의 48.5%, 사망자수의 53.5%를 차지하고 있어('11년 기준), 야간 교통량 비중 감안 시 주간대비 위험도 3배에 달하나 실규모 실 증실험은 거의 전무하다. 이와 같이 도로의 악영향 및 악천후에 의한 피해는 심각한 사고 또는 피해를 입히는 것으로 나타났으 며, 이를 예방하기 위한 관련된 연구 및 기술 개발이 진행되고는 있으나 산발적이며 실증실험 등이 없어 과학적인 효과 입증이 어려운 상황이다. 한국건설기술연구원에서는 이러한 사회적 문제로 대두되고 있는 교통사고 등을 근본적으로 해결하고, 국가 기준을 재검토하여 적정 기준을 정립하기 위하여, 기상환경 재현 도로 성능평가 실험시설을 유치하 여 국토교통부 국토교통기술촉진연구사업으로 경기도 연천에 구축중에 있다. 각 실험시설의 목표 사양은 표 1과 같다. 향후 실험시설 구축뿐만 아니라 실험시설 운영계획, 연구 활용계획 및 활성화방안을 수집하여 관련 연구, 성능평가 ․ 인증 사업에 활용할 경우 국내 도로 안전 및 시설 성능 수준이 한층 높아질 것으로 기대된다.

PURPOSES : The purpose of this study is to revise the weight to power ratio of the representative truck in S. Korea. So far, S. Korea has been using the unit lb/hp, and the construction machines were not considered in the evaluation of the performance of trucks. METHODS : This study was performed to recommend the use of ISO system of units, and to analyze the weight to power ratios of the representative trucks in S. Korea, including the dump trucks, concrete mixer trucks, and asphalt and concrete diffusers. RESULTS: From this study, the 85 percentile value of the weight to power ratio of the trucks in S. Korea’s was found to be 103.6 kg/kw. CONCLUSIONS : The performance standard for the representative truck has to be increased upward, considering the travel pattern of the dump trucks, concrete mixers, and asphalt and concrete diffuser trucks, travel distances, narrow area (work zone) of operation, and the saving in construction budget for climbing lane. Based on this study, the weight to power ratio of the representative truck in S. Korea could possibly be revised to 100~110 kg/kW.

PURPOSES : The purpose of this study is to suggest a basis for setting appropriate safety goals specifically related to the threshold zone luminance in a vehicular traffic tunnel. . METHODS: In the test, drivers were divided into two groups. One group consisted of all drivers (average drivers) group with an age ratio of drivers holding domestic driver's license and driver group by age to produce threshold zone luminance in the tunnel. The threshold zone luminance produced as a result was used to analyze how it affects the safety level of each driver group and provide a basis for setting an appropriate safety criterion that can be used to determine threshold zone luminance. We used test equipment, test conditions, and ananalysis of threshold zone luminance identical to that reported by ChoandJung(2014) but the values of adaptation luminance in our analys is were expanded to range from100 to10,000 cd/m2. RESULTS : Adaptation luminance and threshold zone luminance are found to be related by a quadratic function. The threshold zone luminance needed by older drivers to ensure a certain safety level is significantly higher than that for drivers of other age brackets when adaptation luminance increases. 56% of older drivers are at an increased risk of an accident at the same luminance for which the safety level of average drivers is 75%. The safety level that can be achieved for older drivers increases to above 60% when threshold zone luminance level is set with the goal of attaining a safety level of more than 85% for average drivers. The safety level that can be attained for average drivers is above 90% when the threshold zone luminance is high enough to ensure over 75% in the safety level of older drivers. Results of this study are applicable to highways and others whose designed speed is 100 km/h. CONCLUSIONS : Threshold zone luminance determined on the basis of drivers having average visual ability is of limited value as a performance standard for ensuring the safety of older drivers. Hence, safety level for older drivers should be considered separately from safety levels for drivers with an average ability to avoid risk. Upward adjustment of older drivers' safety level in the process of determining appropriate threshold zone luminance in a vehicular traffic tunnel may bring both tangible and intangible benefit as a result of reducing accidents. However, there is an associated dollar cost arising from installing and operating lights. As a result, the economic impact of these trade-offs should also be considered.

PURPOSES : This study has been performed with the objective to determine threshold zone luminance of adaptation luminance by target safety level in a vehicular traffic tunnel with design speed set at 100km/h . METHODS: The study made a miniature capable of portraying changes in luminance distribution within 2×10。conical field of view of the driver approaching to the tunnel for the test. Test conditions were set based on justifications for CIE 88-1990's threshold zone luminance used as a reference by domestic tunnel light standards (KS C 3703 : 2010). Luminance contrast of object background and object is 23%, object presentation duration is 0.5 seconds, and size of the object background is 7.3×11.5m2 RESULTS: Threshold zone luminance was set within adaptation luminance of 100~3,000cd/m2. Adaptation luminance and threshold zone luminance based on 50%, 75% and 90% target safety level all showed a relatively high linear relationship. According to findings in the study, it is not appropriate to specify the relationship between adaptation luminance and threshold zone luminance as luminance ratio. Rather, direct utilization of the linear relationship gained from the study findings appears to be the better solution. CONCLUSIONS : Findings of this study may be used to determine operation of threshold zone luminance based on target safety level. However, a proper verification and validity of test results are required. Furthermore, a study to determine proper threshold zone luminance level considering target safety level reviewed in this study and various decision-making factors such as economic conditions in Korea and energyrelated policies should be carried out in addition. Additional tests on adaptation luminance greater than 3,000cd/m2 will be performed, through which application scope of the test findings will be broadened.

PURPOSES : Traffic congestions which occur in the intersections of arterials lead to mobility and environment problem, and then traffic agencies and engineers have been struggling for mitigating congestions with greenhouse gas emissions. As an alternative of solving theses problems, this study is to introduce a low-cost and high-effectiveness countermeasure as unconventional intersections which are successfully in operation in U.S.. The main feature of unconventional intersections is to reroute turning movement on an approach to other approach, which consequently more green time is available for the progression of through traffic. Due to improved progression, this unique geometric design contributes to reduce delays with greenhouse gas emission and provides a viable alternative to interchanges. This study is to evaluate the potential operation and environment benefits of unconventional intersections. METHODS: This study used the VISSIM model with Synchro and EnViVer. Synchro is to optimize signal phases and EnViVer model to estimate the amount of greenhouse gas emissions by each condition. RESULTS : The result shows that unconventional intersections lead to increase the capacity and to reduce greenhouse gas emissions, compared to existing intersections. CONCLUSIONS: Unconventional intersections have the ability to positively impact operations and environments as a low-cost and higheffectiveness countermeasure

PURPOSES: This study is to develop Right-Turning Channelization Design Models of Semitrailer at Intersections by regression of vehicle tracking simulation. METHODS: Based on the literature review, it was indicated that right-turning channelization design guide of semitrailer is too complex and is not reflected turning speed and approach angle. To verify effectiveness of right turning semitrailer trajectories according to the changing turning speed and approach angle, vehicle tracking simulation was executed. And then, simulation results were analyzed for modeling design elements; minimum turning radius, swept path width, arc length, width of triangle island, of right-turning channelization using regression methods. RESULTS : When the turning speed is getting higher, minimum turning radius, arc length, width of triangle island increased and the approach angle lower, swept path width, arc length, width of triangle island reduced. The turning radius completely reflected by turning speed. CONCLUSIONS : In this research, it was investigated how much design elements are changed according to the turning speed and the approach angle of semitrailer. The developed right-turning channelization design models can help engineers to easy and comfortable design at various conditions.

PURPOSES : Road lighting facilities increase the visibility of road at night in order to improve traffic driver safety and comfort. Generally speaking, current pole lighting has a tendency to create problems of glare and flicker. The phenomenon of glare gives discomfort due to increase of scattered light, when high luminance is in driver's field of view. The phenomenon of flicker occurs due to the driver passing through discontinuous pockets of pole lighting areas. These phenomenon increase eye strain and decrease driver safety. METHODS : Low height line lighting that distributes light lower than driver's eye level has been developed and evaluated to reduce the problems linked to current pole lighting. A test was undertaken with 4 conditions(turn on the general pole lighting, turn off alternate pole lighting, turn on the line lighting and line lighting with 50% dimming). A driver written survey was conducted in order to gain driver feedback. RESULTS : Pupil size and brow frequency compared with degree in pole lighting are reduced. CONCLUSIONS : Low height line lighting environment makes drivers more comfortable than pole lighting environment and is positive lighting method in the energy saving and landscape aspect.