This paper is about highway asset deterioration rates. Typically, these are difficult to determine. However, using a data collection method adopted in North Carolina (and the resulting data obtained over a 5-year timespan), an approach was developed to determine accurate deterioration rates for several highway assets. This was not previously done, and thus, deterioration was not included as a factor in estimating future maintenance needs for these assets despite the ready availability of the necessary data. This paper focuses on unpaved shoulders and outlines how their deterioration rates were obtained and how such rates can also be obtained for other assets. The resulting deterioration rates are presented and compared over various road systems and geographical regions. With this new knowledge, deterioration rates can now be included in life cycle asset analysis, resulting in more accurate condition predictions and maintenance budgeting. The paper focuses on highway assets and does not address bridge or pavement maintenance.