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Noise and vibration measurements were conducted on eight light vehicles ranging from small compact passenger cars to a large sport utility vehicle on and off shoulder rumble strips of two different designs to assess the input to a vehicle operator when the vehicle departed from the travel lane. The first design was a more conventional design, consisting of cylindrical indentions ground into the pavement at regular 30 cm intervals, and a continuous sinusoidal profile with a peak-to-peak length of 36 cm. Triaxial vibration measurements were made at six locations, including the steering wheel and column, the seat cushion and track, and the front and rear spindles. Interior noise was measured at six locations, one at the operator’s outward ear and five at the front seat passenger (three in the fore/aft locations of the seat and at outboard and inboard ear locations). In addition to the in/on vehicle measurements, pass-by noise levels were made.

A measurement program was completed to assess driver input versus exterior noise generation for four vehicle designs and two different rumble strip designs. The vehicles included a small compact car, an immediate size car, a full sport utility vehicle, and a medium duty dump truck. The first rumble strip was a conventional design providing shorter wavelength input to the tire. The second was designed to provide longer wavelength, more harmonic input to the tire. The measurements included exterior pass-by noise and on-board exterior noise and interior measurements of sound pressure level and vibration level at the seat track and steering column. In general, the results indicated that the longer wavelength strips produced less overall A-weighted pass-by noise with little or no reduction in interior noise and vibration.