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.

ABSTRACT
1. 서론
    1.1. 연구배경 및 목적
    1.2. 연구 범위
2. 문헌고찰
    2.1. 노면표시 재귀반사의 원리
    2.2. 노면표시의 구성 재료
    2.3. 노면표시 재귀반사도 측정 방법
    2.4. 국내외 노면표시 성능 기준
3. 노면표시 현장 조사
    3.1. 조사구간 선정
    3.2. 현장 조사
4. 노면표시 재귀반사도 조사 분석
    4.1. 노면표시 종류별 재귀반사도 분석
    4.2. 도로 종류별 노면표시 재귀반사도 분석
    4.3. 차륜 통과에 따른 노면표시 재귀반사도 감소
    4.4. 젖은 노면에서의 재귀반사도 분석
    4.5. 차량 이동식 장비와 휴대용 장비의 재귀반사도비교 분석
5. 결론
REFERENCES

• 김부일(한국건설기술연구원 인프라안전연구본부) | Kim Booil 교신저자