Origin and Destination Locations

5.2 Data

The data used in the mathematical model was obtained from the FMM model using the methodology and processes outlined in Chapter 4. The key input data includes: origin locations (shippers or producers), destination locations (consumers), origin-destination paths and path links, origin-destination path truckload volume flows, origin-destination path distances, link (arc) distances within each path, line-haul costs for each path, fuel costs for each path, truck miles per gallon (mpg), turnover cost per driver, fixed costs to establish relay points, truck and trailer depreciation costs, truck and trailer maintenance costs, and driver wages. A path is the shortest congested path assignment between each origin and final destination. Each data element is explained further.

5.2.1 Origin and Destination Locations

Origin locations are nodes where freight is produced or originates and final destination locations are nodes where freight is consumed. Non-final destination locations beyond the origin are represented as relay points where truck and trailer equipment are transitioned or exchanged with no actual consumption of goods. Origin locations are typically referred to as shippers where truckload freight (outbound freight) is produced and final destination locations are referred to as final customers where truckload freight (inbound freight) is consumed. There are 203 unique origins or shippers and 210 different final destinations or final customers used in the

mathematical model based on MSA locations. Specific city/state locations for each MSA were determined based on the centroid city/state location for each MSA. Appendix C.1 lists the top 203city/state origins and associated outbound annual truckload flows based on outbound annual truckload flow. Appendix C.2 lists the top 193 city/state destinations and associated inbound annual truckload flows based on inbound annual truckload flow. Using TransCAD mapping software, all origin and destination locations were mapped and shown in Appendix D. For the remaining U.S. states, only MSA level data was considered. The MSA level city/state origin and destination centroid locations along with annual truckload volume flows provide a sufficiently

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dense freight network to model highway truck transportation on a national level within the U.S.

A dense network of freight volume flows is necessary to determine if the relay point concept is a worthy endeavor on a national scale.

An origin-destination pair represents a path where freight is transported between the origin and final destination location. Each path represents a unique shipper and final destination combination. For example, referring back to Figure 12, Dallas, TX is the origin and Mason, TN is the final destination, and truckload freight is transported between the two locations via a truck and trailer combination. In the FMM model, there are 28,889 unique origin-destination paths with origins and destinations represented in each contiguous state (i.e. Hawaii is excluded).

Appendix E shows the top 300 origin-destination paths based on annual truckload flow along with the percentage of truckload volume for each path compared to the overall annual truckload flow. As Appendix E illustrates, each origin-destination path makes up a small percentage of the overall annual truckload volume flow due to the numerous paths and significant truckload volumes associated with each path. In the study, origin-destination paths with a line-haul distance of less than 250 miles were excluded from the analysis because these lanes represent local driving paths where drivers are already home on a daily basis requiring no equipment relaying or special conditions to transition equipment or position drivers to improve driver home time. In other words, the less than 250 mile driving radius represents a local driving

environment. This study is concerned with long-haul paths that require drivers to be away from home beyond one day or to shut-down to comply with federal hours-of-service rules.

Truckload volume flows between the origin and final destination are represented as truckloads. A truckload involves a single trailer, pulled by a truck, containing either a single commodity or multiple commodities unless the trailer is empty and being repositioned to a shipper, customer, or relay point. Truckloads usually weigh out due to the large amount of product weight on the trailer or cube out due to the large amount of space consumed by the products. Typically, in transportation, a truckload refers to freight hauled in either 48’ or 53’

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trailers or containers, but in this study, a truckload refers additionally to refrigerated trailers, tanker trailers, flatbed trailers, etc. Less-than-truckload freight is excluded from the analysis.

An origin-destination text file was created- ODDIST.txt- containing unique origin-destination paths along with the one-way distance between each origin and destination location. As an example of the data structure, Table 2 shows a small portion of the ODDIST.txt table. The ODDIST.txt file contains 28,889 origin-destination paths.

Table 2. Origin-destination paths and line-haul one-way miles example (ODDIST.txt) Each origin-destination path contains truckload volume flow. An origin-destination truckload volume flow text file was created- FLOW.txt- containing unique origin-destination paths along with annual truckload flows between each origin and destination. As an example, Table 3 shows a small portion of the FLOW.txt table. The total annual truckloads included in this study are 205,119,400.

Table 3. Origin-destination paths and annual truckload flow example (FLOW.txt)

Appendix F shows the inbound and outbound truckload flow density at different locations in the U.S. Also, Appendix G shows truckload flow between each origin and destination, which exhibits a high density of truckload flows covering the entire U.S. The high density of origin-destination paths and truckload flows provide sufficient volume flow data to effectively model truckload transportation on a highway network. As an example of a high density truckload flow path, the origin-destination path from Three Rivers, CA (Fresno, CA area) to Chandler, AZ

Origin Destination Miles Wilmington, NC Willow, OK 1,409 Wilmington, NC White Plains, MD 381 Wilmington, NC Westmoreland, NH 836 Wilmington, NC Watson, OK 1,104

Annual Origin Destination Truckload Flow Wilmington, NC Willow, OK 7,366 Wilmington, NC White Plains, MD 8,188 Wilmington, NC Westmoreland, NH 14,284 Wilmington, NC Watson, OK 7,889

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(Phoenix, AZ area) represents the largest number of annual truckload flows (20,046 truckloads) in the data set. The congested shortest path (i.e. based on the FMM freight assignment) from Three Rivers, CA to Chandler, AZ is shown in Figure 13.

Figure 13. Three Rivers, CA (1) to Chandler, AZ (2) path 5.2.2 Transportation Links

An origin-destination path contains numerous transportation links or arcs. Transportation links are small segments of a highway path that contain freight flows between the origin and a relay point, between relay points, and between the final relay point and the final destination for a given origin-destination path. Along each origin-destination path, potential candidate relay points are located at link endpoints associated with the start and end nodes of each transportation link.

As an illustration, Figure 14 shows transportation links between endpoints for section of

highways around the Dallas, TX metropolitan area. In Figure 14, black dots represent endpoints and red lines represent transportation links. There are a total of 134,296 potential relay points at endpoints in the model.

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Figure 14. Transportation links and endpoints (Dallas, TX metropolitan area)

The mathematical model will determine where the relay points will be more optimally established based on the minimization of transportation costs, thus, some links will not contain relay points.

Referring to Figure 12 for the Dallas, TX to Mason, TN path, a relay point is established in Arkadelphia, AR resulting in two driving routes for the path. A driving route exists between Dallas, TX and Arkadelphia, AR and between Arkadelphia, AR and Mason, TN; therefore, the path contains one relay point and two driving routes. Potential routes are defined for each origin-destination path and are dictated by the location of the relay points on the link endpoints.

Potential routes are located in the ROUTES.txt file. As an example of the text file, Table 4 shows a small portion of the ROUTES.txt table. Routes are typically from one location to another location (e.g. relay point to relay point, origin to relay point, relay point to final destination) within an origin-destination path. A route and path are equivalent when a path does not contain a relay point. A route is a subset of a path.

57 Origin Destination From Relay

To

Table 4. Origin-destination path with From Relay and To Relay points (ROUTES.txt) In Table 4 above, the path is from Wagoner, OK to Gage, OK. Link endpoints are termed From Relay and To Relay in Table 4. The From Relay column defines the begin point (node) for each link and the To Relay column defines the end point for each link for the given origin-destination path with the 1 in the Route column representing the presence of a route on a given link. A 0 route value represents the absence of a route for a given From Relay-To Relay link. The

numerical values in the From Relay and To Relay columns represent city/state code numbers that cross reference to actual city/state names or locations. A single route on a given path from the origin to the final destination with no intermediate relay points would indicate that a relay point was not established on the path, and freight flows directly from the origin to the final destination without passing through a relay point. Considering the example in Table 4 above, if a relay point

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was established at point 2 and 4 only, then, there would be a route from point 306 to point 2, from point 2 to point 4, and from point 4 to point 250. Point 306 is a code value representing

Wagoner, OK (the path origin point) and point 250 is a code value representing Gage, OK (the path final destination point). The relay points and routes must be sequenced correctly in order to properly define the path. There are 6,200,619 potential routes in the model data set. Each path consists of an average of 214.6 potential routes.

Each potential route contains a line-haul or one-way distance, which is defined in the DIST.txt text file. The DIST.txt table contains 6,200,619 rows of information (i.e. a row for each potential route) similar to the ROUTES.txt file. The distances are represented in miles, but the distances could be represented in other distance units such as kilometers, meters, etc. Table 5 shows a small portion of the DIST.txt table.

Table 5. Origin-destination path with From Relay and To Relay points and distance (DIST.txt)

From Table 5 above, for the given origin-destination path, the one-way distance between From Relay 210 and To Relay 2 is 50 miles.

Additionally, each route contains a line-haul cost per mile, which is defined in the COST.txt file. The cost per mile includes all variable costs outside the scope of the depreciation costs, fuel costs, maintenance costs, and driver pay. Depreciation costs, fuel costs, maintenance costs, and driver pay are significant individual costs and are captured individually in the

mathematical model. In the transportation industry, variable costs are usually represented as a mileage rate, but other units can be used as well, such as, an hourly rate, a daily rate, a payload weight based rate, rate per hundred pound, etc. Similar to the ROUTE.txt and DIST.txt files, the

Origin Destination From Relay To Relay Miles

Wilmington, NC Willow, OK 210 2 50

Wilmington, NC Willow, OK 210 3 100

Wilmington, NC Willow, OK 210 4 150

Wilmington, NC Willow, OK 210 5 200

Wilmington, NC Willow, OK 210 6 250

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COST.txt file contains 6,200,619 rows of information. Table 6 shows a small portion of the COST.txt table.

Origin Destination From Relay To Relay Mileage Rate

Wilmington, NC Willow, OK 210 2 $0.55

Wilmington, NC Willow, OK 210 3 $0.59

Wilmington, NC Willow, OK 210 4 $0.57

Wilmington, NC Willow, OK 210 5 $0.46

Wilmington, NC Willow, OK 210 6 $0.66

Table 6. Origin-destination path with From Relay and To Relay points and Mileage rates (COST.txt)

From Table 6 above, for the given origin-destination path, the line-haul cost per mile between From Relay 210 and To Relay 2 is $0.55. As exhibited in Table 6, mileage rates are different for each From Relay-To Relay combination because line-haul costs tend to be somewhat different between locations due to economic market conditions. For example, the overall line-haul truck rate inbound to the state of Florida compared to the line-haul rate outbound from the state of Florida can be as much as a $1.00 per mile more expensive since there is minimal truck freight coming out of the state of Florida. Since it is difficult to find freight outbound from Florida, the truck rate inbound to Florida is expensive while the outbound rate from Florida is very

inexpensive. Economic market conditions dictate truck rates for all regions of the U.S. Line-haul costs make up approximately 25%-30% of the total transportation cost. To establish relay points on a given path, link line-haul costs are required for a given path in order to represent the appropriate market-to-market transportation costs. The cost per mile rates were obtained as confidential information from a large transportation company; therefore, the mileage rates shown in Table 6 have been modified and do not exhibit actual rates. The actual rates were used in the mathematical model.