Tire noise lacks a settled generation mechanism and control solution

Evidence

Tires are often the loudest noise source on a vehicle, but there is no agreement as to exactly how the noise is generated, nor therefore how to control it. Considerable research has gone into this problem, but it seems that practicable solutions have not been forthcoming. Safety and traction must come before noise in the list of priorities. Road surfaces differ considerably, and the dominant noise mechanism may also differ. It does seem likely that mini-jets are created by a kind of “watermelon seed” effect as the approaching tire closes the last gaps to the road; a “pop” may be created as a gap suddenly opens up as the tire rolls away. It costs about $2 million per mile to install sound barrier walls near highways; tire noise research may be cheap by comparison. — Eric J. Heller, Why You Hear What You Hear- An…, 1348

Categorization

• QUESTION: The watermelon-seed squeeze-out and rolling-open pop mechanisms are speculative hypotheses worth chasing in primary literature on tire acoustics.
• SHARE: Worth sending to an acoustics or highway engineer: the $2M/mile sound wall cost vs. under-researched tire noise mitigation.