This post features an analysis of data from the Minnesota Transportation Finance Database.
What matters in transportation improvement is not just the money spent in one single year, but also the accumulated amounts invested over a long period of time. With data available through the Minnesota Transportation Finance Database, Jerry Zhao develops two measures of long-term accumulated transportation capital stocks in Minnesota counties during the period of 1995-2011, taking into consideration annual spending, depreciation, and the fluctuation of highway construction costs.
One transportation capital stock is related to local road investments incurred by the counties, and the other about trunk highway construction and maintenance administered by MnDOT within each county. Figure 1 and Figure 2 shows two snapshots of the stocks, respectively, in 1995 and 2010. We can visualize how each stock changes over time, and also compare the size of two different stocks since the figures are prepared in the same scale.
For details about the two measures, see a recently published CTS research report: Transportation Investment and Economic Development in Minnesota Counties. The report finds that investments in local roads and trunk highways show positive returns in property tax values in Minnesota counties.
The complete data about the research, including the two transportation capital stocks, are open for download. With the complete information about the two stocks at the county level during 1995-2011, a county could develop a historical view about the trends of transportation development within the county, and then compare the stocks to those of other counties, which could be neighboring counties or others that are considered comparable or competing peers.