On Determining the Relationship Between Vehicle Value and Interior Noise

A PC based survey tool has been used to measure the value of a luxury vehicle as a function of its interior noise level at 70 mph. Two straight lines were required to fit the change in value (measured in dollars) with noise level depending upon whether noise was greater or less than a baseline level of 66 dB(A). The slopes of the lines differed by a factor of two with the value loss curve asociated with a noise increase from the baseline level being the steeper of the two. A difference in the value relationships between gains and losses in this manner is expected from prospect theory. When the noise level in dB(A) was adjusted to represent a sones-like scale using a conversion based upon a broadband noise spectrum, the measurements followed a single straight line reinforcing the view that the sones scale is more nearly a “pure” psychometric scale than dB(A). The results also suggest that, when persons are asked for their willingness to pay, their response threshold for losses is much more sensitive than their threshold for gains. The findings are discussed in terms of their implications on designing automobiles for competitive markets.