ATS Consulting was retained by VTA in 2006 to assist them address a number of noise and vibration issues that developed when the Vasona light rail line was opened. The specific issues included noise from grade crossing bells, ground-borne vibration, wheel/rail noise, and reflected noise off the bottom of an overpass. ATS performed measurements to characterize the current conditions and helped VTA develop strategies to address the issues. The approaches recommended included modifying the crossing bells to reduce the noise radiated toward residences, minimizing the bell ring time while staying within the CPUC requirements.



So that variances would not be needed, adjusting bell sound levels towards the bottom end of the acceptable range, and acoustical treatment of an overpass to reduce noise reflected towards neighboring residences. VTA is currently in the process of implementing the mitigation measures.