PURPOSES: The rumble strip installed at the highway near the tollgate has the purpose to reduce the vehicle velocity or prevent sleepiness by awakening people to the danger. These rumble strip has different vibration decibel from the rumble strip shapes, resulting in some fatigue damage to human because a driver suffers from a lot of stress and displeasure. In this connection, the objective of this paper is to analyze the vibration decibel perceived by a driver in the vehicle under some conditions. METHODS: The vibration decibel conveyed from the tire can be analyzed. The frequency analysis methods were used according to DFT (Discrete Fourier Transform) analysis, FFT (Fast Fourier Transform) analysis, CPB (Constant Percentage Bandwidth) analysis. But the frequency analysis method in this paper is the 1/24 OCT(Octave) band analysis because of the convenience of the analysis and the overall vibration amplitude along the frequency. RESULTS : By using the results of the vibration decibel after analyzing the 1/24 OCT band analysis, these results can be compared from some conditions (e.g., rumble strip shape, uniform velocity of a vehicle, road condition, mass of a vehicle). As a result, the numerical values of decibel are not directly proportional to the vehicle velocity. CONCLUSIONS : At the condition that a vehicle is passing by the rumble strip, the value of a vibration decibel at the rumble strip of the cylinder shape is smaller than the rumble strip of rectangular shape regardless of the rumble strip depth and width. At the mass condition, the more a vehicle is massive, the more the vibration decibel increases. At the road condition, the vibration decibel at the wet road is smaller than the value at dry road condition.

PURPOSES: This research investigates traffic noise characteristics as change the transverse rumble strips shape from rectangular to cylinder at toll plaza of highway. METHODS : The traffic noise was investigated at two different places at toll plaza of highway. One is modified grooving, another is employed cylinder shape of TRS instead of rectangular shape of TRS. A measurement of traffic noise was conducted at same location and time period. The traffic volume information was gotten from office of highway office and vehicle speed was measured by speed measuring device. The traffic noise measurement was conducted from 13:00 to 23:00 and by pass-by method. Also, the traffic noise was measured behind noise barrier. Various distance from noise barrier(7.5m, 30m, 50m) and different heights(1.2m, 3m, and 5m) were parameter for measurement of traffic noise in this study. RESULTS : The class 1 vehicle was contributed from traffic volume which was increased 1,500. However, the distribution of traffic speed didn’t change compare to previous investigated period. From this study, It was found that the external traffic noise was changed as function of geometric shape of TRS. The external noise from modified grooving was less than 1.2dB(A) of the current TRS. A difference of traffic noise was 20dB(A) before and after barrier. It came from a noise barrier effect as reduction of traffic noise. According to investigate a traffic noise distribution near barrier, there is similar noise characteristic as function of height at 7.5m distance from noise barrier. Also, There is no different traffic noise between 30m and 50m from source of the noise of sound barrier. CONCLUSIONS: Based on this traffic noise investigation result, there is a clear characteristic difference as changed TRS shape. The traffic noise was reduced by changed TRS shape. Specially, traffic noise was decreased although the traffic volume was increase for same investigation time and period. It is implied that cylinder type of TRS significantly reduces the traffic noise. The specification of various TRS will be studied in the future.

PURPOSES: This study is to investigate a generated traffic noise when vehicle pass over a transverse rumble strip at toll plaza of highway. METHODS: To investigate traffic noise at toll plaza of highway, Pass-by method which is the most common used for measuring traffic noise was adopted and the traffic noise at toll plaza was measured for 10 min per hour for 11hours(13:00~24:00). RESULTS: The measured traffic noise by pass-by method was changed as function of the transverse rumble strip configuration. Generally, the maximum difference among three noise measurement sections was 7 dB(A). It might be related with traffic speed. Also, the measured traffic noise was strongly generated from a passenger car which was 2 axle. It means that the most of traffic noise on the road is generated at tire/pavement interface of the passenger car. CONCLUSIONS: The traffic noise was strongly related with vehicle speed and transverse rumble strip configuration on the road. For driver safety, the transverse rumble strip is definitely necessary. However, the complaints from residents near highway was increased by traffic noise from transverse rumble strip. Therefore, To satisfy both safety and reduction of traffic noise, the development of configuration of transverse rumble strip is necessary in the further study.

PURPOSES: This study evaluated a measuring technique for tire-pavement interaction noise that uses a noble close proximity (NCPX) method as well as for noise level measured inside of a car (e.g., Inside Noise Level) in term of rumble strips constructed at a tall gate. METHODS: According to the measurements of NCPX and inside noise level (INL), 1/3 octave band frequency analysis and overall noise level calculation were conducted in order to evaluate noise levels of NCPX and INL, depending on types of rumble strips. RESULTS: The tested sections of general concrete pavement surface and two different types of rumble strips were evaluated, using 1/3 octave band frequency analysis and overall noise level. From the analyzed results, it can be concluded that rumble strips generate a relatively huge noise levels when compared to the concrete pavement surface. CONCLUSIONS: Noting that above 3 dBA different noise levels can let drivers know that they are getting close to toll gate; therefore, they should apply their brakes. Thus, the noise levels of rumble strips are required to be reduced, based on considering the neighbors living near toll gates.

국내 도로의 주행안전성을 확보하기 위하여 2000년에 처음으로 노면요철 포장을 도입하였다. 본 공법의 효과가 증명되면서부터 시공물량은 매년 증가하였다. 본 연구진은 기존형태를 개선하여 본선 콘크리트 포장부 시공 시 동시에 노면요철 포장을 설치하는 형식을 제안하였다 노면요철 포장 시공장비를 제작하여 평택~음성 고속국도에 시험시공을 하였으며 그 효과를 분석하였다. AASHTO에서 제안한 식을 이용하여 횡방향 정지거리를 산출한 결과, 개선된 노면요철 포장의 횡방향 여유 폭이 0.5m 더 확보되어 기존형태보다 더 안전한 것으로 나타났다. 소음도 평가결과, 노면요철 포장이 없는 구간을 주행할때보다 약 3.5~9dB(A)까지 더 크게 소음이 발생하여 졸음을 예방하거나 운전자의 환경을 개선시키는 것으로 나타났다. 진동평가에서는 주로 사람의 안구에 영향을 주는 주파수 영역대의 진동이 지배적인 것으로 나타났다. 주행 후 운전자들의 설문조사 결과에서는 개선된 형태가 기존형태보다 소음이나 진동에서 큰 차이는 없지만 주행상의 안정감이 더 큰 것으로 나타났다. 따라서 개선된 공법을 도로에 확대 적용할 경우, 기존보다 교통사고 및 사망자수를 줄일 수 있을 것으로 평가된다.

노면요철포장은 1950년대 처음 설치된 후 사고감소효과에 대하여 여러 가지 연구가 있어왔다. 대부분의 연구에서 주로 졸음과 부주의 사고를 예방하는 것으로 알려져 있다. 본 논문에서는 고속도로 377개소에서 4년 동안 수집한 교통사고를 바탕으로 노면요철포장 설치 전 후에 사고감소원인과 환경을 분석하였다. 분석결과 노면요철포장 설치 전 후 교통사고를 비교할 때 -200건/2년(-32.3%) 감소하여, 노면요철포장 설치시 사고감소 효과가 있는 것으로 나타났다. 세부교통사고 원인분석결과 노면요철포장 설치효과가 유의하다고 할 수 있는 교통사고원인 항목을 제시할 수 있었다. 졸음, 과속, 주시태만, 부주의, 차량결함, 안전거리 미확보 교통사고감소가 유의하였다. A, B, C 등급 사고의 경우 교통사고감소가 유의하였다. 기상 상태 원인분석결과 맑음, 비, 흐림 기상상태에서 노면요철포장으로 인한 교통사고감소가 유의하였다. 본 논문 결과는 그동안 졸음 혹은 부주의 교통사고우려에 대응하도록 한 기존 노면요철포장 설치기준보다 원인인자를 명확히 하고 확장하여 고속도로 교통사고감소에 기여할 것으로 생각된다.

고속도로의 교통사고는 다양한 원인들에 의해 발생되고, 그중 운전자의 부주의는 가장 중요한 교통사고 원인으로 알려져 있다. 주의 및 규제표지와 노면요철포장 등의 도로안전시설은 이러한 운전자 부주의를 막기 위해 설치 운영되고 있다. 본 연구에서는 서해안고속도로 일부구간에 설치된 길어깨-노면요철포장의 교통사고감소 효과를 분석하기 위해 C-G 방법 (Hauer에 의해 개발된 비교그룹을 이용하는 사전 사후 분석방법)을 수행하였다. 분석결과 길어깨에 도로요철포장을 설치한 도로는 설치하지 않은 도로에 비해 차도이탈사고가 연간 2.43건 정도 감소한 것으로 나타났으며 감소율은 0.38(표준편차 0.21)인 것으로 나타났다. 차도이탈사고는 교통사고 중 길어깨-노면요철포장 설치에 가장 민감하게 영향을 받는 사고형태이다. 본 연구를 통해 서해안고속도로에 설치된 길어깨-노면요철포장은 교통사고 감소에 기여한 것으로 분석되었으며, 특히 차도이탈사고가 현저하게 감소된 것으로 분석되었다.