PURPOSES : Aiming to evaluate the consistency of road markings at night, the luminance values of road markings at night were compared for merging and diverging areas. METHODS : To evaluate the consistency of road marking at nighttime in merging and diverging areas, the highway geometric structures and luminance of the road markings were collected and analyzed together at the merging and diverging areas. "Luminance" in this study referred to the overall luminance of the road markings as reflected together from surrounding lights, such as moonlight or artificial lights. The luminance of the road markings 90 m ahead of the driver were used. The measured luminance values were analyzed based on the difference ratios and an analysis of variance. RESULTS : Based on a grouping of three categories (interchanges (ICs), merging, and diverging areas), it was found that the difference ratios and analysis of variance values from the ICs and merging and diverging areas were not consistently acceptable. CONCLUSIONS : After evaluating the consistency of road markings at night in the merging and diverging areas, it can be concluded that there is a need for more consistency in the luminance on merging and diverging areas on highways. To enhance consistency, more dedicated lighting guidance for merging and diverging areas on highway areas may be necessary.

PURPOSES : The retroreflectivity of pavement markings for road safety was evaluated. METHODS : Field tests of pavement markings, which are characters, symbols, crosswalks, and stop lines, but do not include line markings, were conducted using a portable retroreflectometer with the purpose of evaluating the retroreflectivity according to the type of pavement markings and roads. Furthermore, changes in retroreflectivity due to wheel passing and wet conditions were evaluated. Here, 192 test points for evaluating the retroreflectivity of pavement markings, 5 test points for evaluating reductions in retroreflectivity during conditions of wetness, and 28 test points for checking variability due to type of testing device were selected on major and minor arterial roads in Seoul. RESULTS : The average retroreflectivity of pavement markings measured in this study was 115.7 (mcd/m2·lux), which is lower than the minimum retroreflectivity required six months after installation but higher than the minimum remarking retroreflectivity required by Seoul city. The retroreflectivity of pavement markings measured on minor arterial roads was 69.1% of that on major arterial roads. The average retroreflectivity of pavement markings was reduced to 43.1% by wheel passing, which is below the remarking criterion. The average retroreflectivity measured on wet pavement markings was 43.7 (mcd/m2·lux), which is a ninth of that under dry conditions. The test results showed that retroreflectivity in the rain was much lower than the required value in the case of rain, which is 175 mcd/m2·lux, as issued by Seoul city. Compared with mobile retroreflectometers, a portable retroreflectometer produced 17% higher retroreflectivity based on the results of 28 test points. CONCLUSIONS : Based on the field tests, the retroreflectivity of pavement markings, i.e., characters, symbols, crosswalks, and stop lines, was higher than the average remarking criterion. However, the retroreflectivities of pavement markings passed by the wheel or in rain were lower than the remarking criteria. Considering that the remarking criteria in Seoul city are higher than those in Europe and the test results in this study indicate much lower values than those required in Seoul, further study is necessary to be able to properly modify the criteria for retroreflectivity.

PURPOSES : In this study, the luminance of night road markings was measured in a tunnel of length 200 m or less. The purpose of the project is to evaluate the consistency of night road markings. METHODS : In this study, field measurements were conducted to achieve the purpose of this study. Five tunnels with lengths of less than 200 m were selected to measure the luminance value of the road markings. The analysis of the difference in road markings between the inside and outside points of the tunnel and the analysis of alternative tunnels and points were used to assess the consistency of road markings in tunnels. RESULTS : The average luminance of the tunnel’s night road markings was 9.7, and the standard deviation was 3.0. The analysis of variance for the tunnel and point indicated that the p-value was less than 0.05 and was inconsistent. CONCLUSIONS : In conclusion, consistency was assessed by measuring the luminance value of the short tunnel of length 200 m in the Cheongju Sangju Expressway, and it was confirmed that the luminance of the road markings was not consistent with the tunnel and point. Finally, it is necessary to control night lightings on roads outside the tunnel or adjust lighting facilities in the tunnel to enhance the consistency of luminance.

OBJECTIVES : Visibility at night can be improved by using retroreflection for short distances and phosphorescent line markings for long distances. In this study, we analyzed the characteristics of the phosphorescent line marking through a laboratory luminance test. Field performance analysis was performed through tests conducted on the road. We also examined the luminance measurement methods using the digital image obtained during the phosphorescent visibility evaluation. METHODS : In this study, the laboratory luminance test of the phosphorescent line marking was conducted using seven specimens to characterize the luminance changes according to the type of the glass beads, the thickness of the phosphorescent line marking, and the brightness and irradiation time of the light source. Phosphorescent and general line markings were made at 150 m to investigate the field luminance performance. A preliminary review of the luminance measurement methods was made using a digital image from a digital singlelens reflex (DSLR) camera. The measured luminance ratio of the general and the phosphorescent line markings was compared with the calculated luminance ratio using luminance analysis. RESULTS: Through the laboratory luminance test, it was seen that the change in luminance, which corresponds to the brightness of the light source, appears large but the influence of the thickness and irradiation time is low. The field performance test of the phosphorescent line marking conducted on the road involved measuring the luminance on the day the marking was made and 7 days after the marking was made. The luminance was found to be 190 mcd/m2 at 30 min after sunset and approximately 10-12 mcd/m2 4h after sunset. The results of the luminance test were captured using a digital image for each time group. The luminance ratio of the phosphorescent line marking, when compared to that of the general line marking, showed a similar trend within a 13% maximum error. Additionally, when this luminance ratio is compared to the direct field measurement, it could be confirmed that the luminance ratio, as captured in the digital image, showed a similar tendency. CONCLUSIONS : 1) The change in luminance corresponding to the brightness of the light source is significant in comparison with that corresponding to the thickness and the irradiation time. In addition, the results of the field test for the phosphorescent line marking satisfied the phosphorescent fire protection standard. 2) We examined the validity of the luminance measurement method using a digital image and we concluded that the change in the luminance ratio shows a similar tendency in both the cases. The results can form the basis for luminance measurement methodology for the construction and maintenance of phosphorescent line markings.

교통안전시설물은 도로 이용자가 필요로 하는 정보를 사전에 전달하고, 또한 행동을 동일하게 통제함으 로서 도로상의 안전 확보 및 교통 소통을 증진하는 시설이다. 교통안전시설 중 선으로 표시하는 중앙선, 구분선 등의 차선은 운전자에게 진로 및 도로선형 등의 시각적인 정보를 제공함으로써 운전자의 안전하고 편리한 운행을 돕는 중요한 역할을 한다. 최근 야간에 차선이 보이지 않아 운전자들의 야간 주행안전성이 문제가 되고 있다. 이와 같은 야간 주행 문제는 최근 3년간 야간 교통사고 사망자 수가 전체 사망자 수의 52.8%로 절반 이상을 차지할 만큼 대안 마련이 필요한 실정이다. 노면표시의 시인성은 자동차 전조등에서 나오는 빛을 유리알에 의해 재귀반사 함으로써 이루어진다. 하지만 유리알에 의한 재귀반사는 전조등 거리 에 따른 시인거리에 한계가 있고, 전조등 빛이 닿지 않는 구간인 굴곡이 심한 산지부 도로나 커브가 있는 회전구간에서 시인거리가 극히 제한될 수밖에 없다. 해외에서 주로 연구되고 있는 축광 노면표시는 재귀반 사 방식의 한계를 극복할 수 있고, 조명시설이 부족한 구간에 설치 시 야간 주행안전성을 향상시킬 수 있 다. 하지만, 대부분 축광에 의해 도료 자체에서 방출되는 빛만을 이용하여 시인성을 확보하는 기술로 자동 차의 전조등이 비추는 영역에서는 축광에 의한 시인성 효과를 얻기가 어렵다. 따라서 본 연구에서는 축광 노면표시에 유리알을 살포하여 자동차 전조등이 비추는 근거리에서는 재귀반사를 통한 시인성을 확보하 고, 원거리에서는 축광에 의한 시인성을 확보할 수 있는 축광 노면표시 개발을 위한 기초실험을 하고자 한 다. 이를 위해 유리알 성능과 노면표시 두께에 따른 축광 노면표시의 재귀반사도 및 휘도 성능을 비교･분 석하였고, 본 연구 결과는 향후 축광 노면표시 개발에 필요한 기초자료로 활용할 수 있다. 본 연구에서는 축광 노면표시에 유리알을 살포하여 재귀반사와 휘도를 동시에 얻을 수 있는 노면표시 개발을 위한 기초실험을 수행하였다. 본 연구를 수행하며 도출한 결론은 다음과 같다. 1. 축광 노면표시 의 색도는「KS M 6080」기준을 만족하는 것으로 나타났다. 2. 축광 노면표시의 건조상태 재귀반사 실험 결과, 축광 노면표시에 유리알 살포시 경찰청 재귀반사 기준인 240 mcd/(㎡･Lux)를 모두 만족하는 것으 로 나타났다. 습윤상태 재귀반사 실험 결과도 유리알 1종 1호를 제외한 유리알 1종 3호와 2종 1호를 살포 한 축광 노면표시 시편은 경찰청 우천시 재귀반사 기준인 100mcd/(㎡･Lux)를 만족하는 것으로 나타났 다. 이에 따라 축광 노면표시에서도 유리알 살포시 자동차 전조등에 의한 재귀반사로 근거리 시인성 확보 가 가능할 것으로 판단된다. 3. 축광 노면표시는 일반 노면표시에 비해 유리알을 살포하지 않아도 도료 자체적으로 건조상태 재귀반사 성능이 높은 것으로 나타났다. 이는 축광 노면표시 도료가 자체적으로 빛 을 발산하기 때문인 것으로 판단된다. 4. 축광 노면표시에 유리알 살포시 축광 성능이 개선됨을 확인하였 고, 유리알 굴절률이 높아질수록 휘도 값이 증가하는 것으로 나타났다. 또한 축광 노면표시의 두께가 두 꺼워질수록 휘도가 증가하긴 하지만 일정수준 이상으로 두께가 증가할 경우 축광 성능이 포화되어 더 이 상 휘도가 증가하지 않는 것으로 나타났다.