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8 CHAPTER 2 User Guide for DIETT DIETT consists of three submodules. This chapter pro- Step 5--Scoring Method. Select the scoring method by click- vides instructions for each submodule. ing on the "Scoring Method" button and changing the key parameters, as seen in Exhibit 3. The scoring formula is a means of preselecting on the basis of estimated net trans- 2.1 DIETT Query System portation costs over the detour distance. The net transporta- The DIETT query system is the first program to trigger tion costs over the detour distance are estimated on the basis when the DIETT icon is clicked on. It is provided primarily to of average cost per ton-mile and a rough estimate of recon- conduct the initial queries and to process the data for the first- struction time. Detailed analysis of the cost comes later, in order prioritization of candidate transportation choke points the DIETT spreadsheet tool, after candidate TCPs have been (TCPs). The program is set to transfer 500 fields or candidate identified and exported. TCPs. With a click on the "Next" button, the output of the queries is automatically transferred to MS Excel where it will The score for each asset is determined by the following be further analyzed and prioritized. formula: To start DIETT, click on the DIETT application icon on the desktop. This will launch the application and generate the query Score = Days of Outage Detour Distance page shown in Exhibit 2. To set the parameters for queries, insert Cost pe er Ton - mile Trucks per Day the information requested on the query page. At the bottom of Days of Outage = 3 Span length Meters of the query page, brief instructions are given for using it (see Reconstruction per Day Exhibit 2).A more detailed version of those instructions is given in the seven steps listed below. (Note that circled numbers 17 Step 6--Sort on a Desired Category. Most of the column head- on Exhibit 2 correspond to the step numbers listed below.) ings on the query page, "Value ($1000),""Detour,""Traffic," "Span Length,"etc. (see Exhibit 2), can be sorted on. The user Step 1--State. Insert the name of the state to be modeled (for may want to use the sort function if the number in "Records" security reasons, data used to illustrate the use of DIETT (see Exhibit 2, circled number 4) exceeds 500. This will cause were altered and entered as the data of an imaginary state-- the program to work with the top 500 records. It is recom- Fredonia). mended that the column "Value ($1000)" be used because it Step 2--Trucks Per Day. Insert the desired category for min- utilizes a weighted approximation of value. imum number of trucks using the trucks per day. Step 7--"Next" and "Quit" buttons. Press the "Next" button Step 3--Span Length (m). Insert the minimum length of the to close the query application and open the spreadsheet TCP (bridge) span in meters. application. Press the "Quit" button to exit DIETT. Step 4--Records. Track the count of candidate TCPs in the "Records" indicator. If the desired number of records is not Users should also be aware of the following: reached (500 is recommended), reset the "Trucks Per Day" and "Span Length (m)" parameters. The two parameters When the NBI database is used and the selected records should be adjusted in a balanced manner; make adjustments indicate that the bridge crosses over a water body, a default to both the truck and span parameters. Resetting of param- for barge traffic is 4 barges per day, with a detour distance eters may be repeated several times to generate the desired of 1 mile. For rail lines using the bridge, a default of 500 rail number of candidate TCPs. cars per day is assumed with 100 miles of detour. These