Deterioration rate plots showing the change in BCI_ave between successive inspections for populations of structures that were inspected in the same year, split by bridge type. The change of condition with time of these populations of bridges has been plotted as the difference between the average BCI scores for the population in each of the successive inspections, weighted by deck area to account for the relative importance of larger structures. The markers have been shaded to indicate the comparison year. The size of the marker has been scaled by the number of bridges that it represents. The weighted average of the plotted comparison years has been plotted on the top as a black bar. Data from 2397 bridges are included in this plot