Return on Investment in Transportation Asset Management Systems and Practices (2018) / Chapter Skim
Currently Skimming:
Pages 145-156
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 145... ...
145 A P P E N D I X E Description of the Southern State Case Study This appendix provides additional details on the Southern State case study described in Chapter 3. The case study was performed to determine benefits realized through the DOT's implementation of a maintenance levels of service approach and new TAM system.
|
From page 146... ...
146 Return on Investment in Transportation Asset Management Systems and Practices collected using a slightly different approach. The reports provided annual data on LOS letter grades by district for each maintenance element, split by category for all districts.
|
From page 147... ...
Appendix E 147 Mapped LOS maintenance categories to maintenance expenditure types and ensured consistent naming conventions over the years; Adjusted maintenance spending data for inflation; Estimated lagged maintenance costs; Aggregated total spending by maintenance category; Pooled LOS data at the category level; and, Mapped districts to NOAA weather stations and average temperature. The research team studied the annual scores for each maintenance element and district.
|
From page 148... ...
148 Return on Investment in Transportation Asset Management Systems and Practices Figure E-2. Total Lagged Maintenance Costs per Mile (in 2014 dollars, 2008–2014)
|
From page 149... ...
Appendix E 149 Table E-3. Average LOS Score by Category.
|
From page 150... ...
150 Return on Investment in Transportation Asset Management Systems and Practices The research team found the following relationships through the initial analysis: The average LOS scores have been declining over time. When spending increases, the actual scores surpass the LOS objectives.
|
From page 151... ...
Appendix E 151 LOS scores by maintenance category, district and year (CTGY) ; and, Average temperatures in each district by year, represented by the departure from normal monthly mean temperature (DPNT)
|
From page 152... ...
152 Return on Investment in Transportation Asset Management Systems and Practices Model Diagnostics The research team ran regression diagnostics after fitting the model to evaluate assumptions and to investigate if any observations were largely influencing the analysis. Model diagnostic procedures involve both graphical methods and formal statistical tests.
|
From page 153... ...
Appendix E 153 Figure E-3. Diagnostic Plots of Residuals.
|
From page 154... ...
154 Return on Investment in Transportation Asset Management Systems and Practices o The effect of the cost of the mean departure from the objectives is not statistically significant before the TAM system is implemented. o The interaction of cost per mile and the TAM system is a significant positive predictor.
|
From page 155... ...
Appendix E 155 then the overall expected change in scores ( ) given the percent change in the lagged expenditure per mile ( )
|
From page 156... ...
156 Return on Investment in Transportation Asset Management Systems and Practices Although it was not possible to demonstrate the effect of implementing the TAM system for the case study, the available data showed significant annual increases in average annual cost per mile from fiscal years 2007 to 2009 followed by significant drops in cost per mile from fiscal years 2010 to 2012. Afterwards, annual average cost per mile started to increase.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.