Noise Reductions From 6’-8’ Tall Solid Safety Barriers
Research Idea Scope
TNM significantly underestimates, and overlooks, the noise attenuation of 6’-8’ tall solid safety barriers (SSBs) because TNM distributes a large amount of noise energy tall in the vehicle profiles at 5 and 12 foot positions above the pavement.. TNM places 63% of the noise energy of an HT at 12’. In Ohio, 65% of all HTs don’t even have a vertical stack, hence, no 12’ noise source. This is why taller noise walls are unnecessarily being built. This research would examine how well 6’-8’ tall SSBs work at attenuating PC, MT, and HT noise. Tire/pavement noise is the dominate vehicle noise source and it is believed by some DOTs that 6’-8’ tall SSBs would provide a quantifiable amount of noise reduction to meet DOT noise reduction criteria. Field test and model the noise reductions of 10-15 6’-8’ tall solid safety barriers along freeways and document the results. Compare the measured results to the modeled results. Compare the results to reductions from typical 12’-16’ taller structural noise barrier results. Another option is to install portable 6’-8’ tall portable concrete barrier along a freeway and test it with and without the 6’-8’ tall portable concrete barrier.
Urgency and Payoff
Highway noise is always a top public concern. Tall sound walls cost $400/LF and are currently acoustically over designed. A 6’-8’ tall SSB can cost as low as $180/LF. With the current version of FHWA TNM, 6’-8’ SSBs are being rejected because of internally-inaccurate-computational assumptions. SSBs are already an established design component of highway infrastructure and could provide two functions: safety and noise attenuation. This provides SDOTs with more less-expensive options to abate noise impacts. Successfully utilizing the results of this study could result in a significant annual costs savings for noise barrier construction and noise barrier maintenance. These savings will compound over time as 6’-8’ tall SSBs are constructed in place of taller structural noise walls.