Response to a change in transport noise exposure: a review of evidence of a change effect.

Environmental appraisals of transport infrastructure plans are generally conducted in situations where there will be a step change, or an abrupt change, in noise exposure. While there has been a number of studies of response to step changes in exposure, and seven previous reviews of subsets of these studies, understanding of human response to a change in noise exposure remains limited. Building largely on these previous reviews, this paper examines the evidence that when noise exposure is changed, subjective reaction may not change in the way that would be predicted from steady-state exposure-response relationships. The weight of evidence, while not incontrovertible, is that when exposure changes, responses show an excess response compared to responses predicted from steady-state exposure-response relationships. That is, there is a change effect in addition to an exposure effect--at least for road studies and at least where the change in exposure results from changes at the source. Further, there appears to be little, if any, adaptation of this excess response with time.