Rumble strip sound level evaluation—Comparison of three designs

Results of sound level monitoring from three types of longitudinal rumble strips installed along the edge of two-lane rural roads are discussed. This study was in response to objections by landowners about unwanted noise caused by vehicles traveling over rumble strips. The ultimate study goal is to provide maximum tactile and tonal sound levels at the driver position while minimizing exterior sound levels. Both exterior and vehicle interior sound levels were measured for three longitudinal edge-of-pavement rumble strip designs—California, Pennsylvania, and Minnesota. Simultaneous digital audio files were also recorded. Three vehicles types were tested at 30, 45, and 60 mph. Comparison of exterior levels and interior sound levels showed that the Pennsylvania design is the quietest, both interior and exterior. Interior levels from the Minnesota and California designs are similar but exterior levels are higher for the Minnesota design. The California design generates two tonal peaks. The Minnesota design gen...