In Service Experience With Traffic Noise Barriers PDF Download

In recent years the Ohio Department of Transportation (ODOT) has reconstructed a number of roadways where asphalt pavements were replaced with random transverse grooved concrete pavements. Upon completion, residents living adjacent to the reconstructed roadways have complained of increased noise levels. The Federal Highway Administration (FHWA) Traffic Noise Model (TNM) is used to determine if predicted traffic noise levels warrant abatement and to design the abatement structures. The public perception problem described above suggests that the model does not result in adequate noise barrier abatement designs near random transverse grooved concrete pavements. The overall goal of this project was to provide ODOT with accurate TNM noise predictions when modeling random transverse grooved concrete pavement highways. Three random transverse grooved PCC roadway sites were chosen for study where high quality sound recordings were taken. Sites 1 (Cincinnati I-275) and 2 (Troy I-75) were chosen to represent the noise quality experienced by residents adjacent to the roadway, where the residential areas were separated from the roadway by sound barriers. Site 3 (Madison County I-70) was chosen to study the attenuation of road noise with distance in an easily-characterized environment; an open soybean cropland essentially level on both sides of the roadway with no noise barrier. Through a paired t-test the research findings determined that the sample means of the TNM average pavement and the ODOT random transverse grooved pavement were not equivalent based upon a level of confidence of 95 percent. An examination of the one-third octave band frequency levels indicated that at frequencies greater than 500 Hz, the measured traffic noise levels exceeded both the TNM average pavement type and TNM ODOT random transverse grooved pavement predictions. However, at frequencies less than 500 Hz the predictions tended to exceed the measurements. It is recommended that the experimental version of TNM developed for this project, using the current ODOT random transverse grooved concrete pavement REMEL, should not be used in practice due to its potential to under-predict traffic noise levels. A new surface texture specification should also be developed for concrete pavements to replace the current specification in order to reduce tire/pavement noise levels while maintaining or improving safety and durability characteristics.