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9 Increased Time En Route. An extreme example is mar- Inventory Cost-related Categories Default Values itime shipping, in which delays can be measured in weeks and the inventory costs in millions of dollars. Increased time % of Cargo High Value - Truck 60% en route affects surface transportation also, but is less % of Cargo Med. Value - Truck 30% noticeable because the time factor is small and the effect is distributed among many small shipments. However, in the % of Cargo Low Value - Truck 10% aggregate, the effect can be significant. The cost associated % of Cargo High Value - Rail 20% with increased time en route is referred to as the detour time factor. % of Cargo Med. Value - Rail 50% Altered Risk. This is the real or perceived risk of the revised % of Cargo Low Value - Rail 30% shipment patterns (route, mode, etc.). The altered risk can be increased risk as well as decreased risk. This impact is % of Cargo High Value - Barge 5% most commonly internalized as the probability of making % of Cargo Med. Value - Barge 25% on-time delivery, or reliability. Changing inventory levels is commonly used to hedge the risk effect. Action taken in % of Cargo Low Value - Barge 70% response to altered risk is referred to as the reliability factor. Alternate Route Reliability - Truck 95% Both of these effects (factors) are addressed in the method- ology. Measuring the impact of these effects required the Alternate Route Reliability - Rail 99% introduction of three sets of data: Inventory Cost: % of Cargo/Year 18% Cargo value--Default values are provided in three cate- gories for each mode: high ($10,000/ton of cargo), medium ($1,000/ton), and low ($100/ton). These are used Exhibit 2. Inventory cost-related categories and default values. to set an estimated value on the rerouted freight. Cargo value is used in the calculation of inventory premiums. Inventory premium--This is the inventory cost as a percentage of cargo value. The default value is set at 18% per year. The premium is applied for the duration of the Users (predominantly state DOTs) should consider assign- disruption. ing responsibility for applying this tool to analysts (1) con- Detour reliability factor--This reflects the reliability of versant with the recommended datasets (and the limitations on-time delivery compared with the reliability perform- of those datasets); (2) with access-controlled workspace ance on the original route. Reliability data are not readily and procedures in place to safeguard the data and infor- available and required the inclusion of estimated values. mation generated through use of DIETT; and (3) with The best estimates may be generated at the state level. The clear guidance as to how the information generated user can enter state-specific estimates. through DIETT is to be documented, communicated, and incorporated into agency policy and budget development The categories and the default values used in determining processes. business inventory costs are shown in Exhibit 2. Users should set up DIETT to operate within or in tan- Algorithms are constructed within DIETT to calculate all dem with CATS-JACE to enable interaction with resident business inventory-related costs using the inventory cost- security-related programs. One example of the applica- related parameters to generate separate impact data for bility of CATS-JACE is its ability, through ArcGIS (ver- transportation-related impacts (costs) and direct economic sion 9.0), a resident program, to improve on "detour" impacts. The summary results are provided in the 11-column (distance) data. A feature of ArcGIS (version 9.0) dis- OUTPUTS worksheet of the DIETT application (see Ex- played in the toolbar as "Browse Bridges" (see Exhibit 4) hibit 3). Of these 11 columns, the first 6 are TCP identifiers and can be used to identify alternative detours through the use the next 5 are impact results measured in absolute (estimated) of GIS information and GIS mapping functions. Other value ($) and as defined percentages. functions of ArcGIS allow users to display the location of candidate TCPs, close off roads (virtually), and develop scenarios for the best detours. A detour can be automati- 2.3 Recommended Use cally measured in additional miles traveled--see "Added Recommendations for obtaining the most benefit from Distance" in Exhibit 5. The detour can also be visually DIETT include the following: designated (see Exhibit 6).

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Exhibit 3. The output page of the DIETT spreadsheet application. Exhibit 4. ArcGIS (version 9.0) toolbar and data display.

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11 Exhibit 5. ArcGIS (version 9.0) detour result dialog box. Normal Route Detour Exhibit 6. ArcGIS (version 9.0) visualization of detour.