Provisional Estimates of FAF O-D Freight Flows by Highway

Charlie Han

MacroSys Research and Technology

May 15, 2007

ObjectiveDevelop Provisional Estimates of FAF Origin-

Destination Freight Flows by Highway

• Measurements: Tons and Value ($)

• Commodity Detail: 2-digit SCTG level

• Types of Origins and Destinations

- Domestic: FAF Regions

- International: FAF Regions and Ports of Entry/Exit

Benchmark Year freight tonnage

Growth in freight tonnage

An “updating” approach

Provisional estimate of new freight tonnage

Freight flow from one region to another

What do we want?Answer: Freight flows by commodity and by FAF O-D

regions

A

B

C

FAF Region

Commodity flows

Method for Domestic O-D FlowsEstimation Steps:

Step 1: The growth in total domestic highway freight tonnage

= Total domestic highway freight tonnage of benchmark year × Growth rate of highway freight calculated from ATA’s trucking tonnage index

National total without region and commodity details

Step 2: Break total growth into growth by commodity

Growth by commodity = Total growth × Shares of commodities in Total Output ($)

National total with commodity details

Method for Domestic O-D FlowsEstimation Steps:

Step 3: Distributing national growth by commodity to FAF regions For Example: X(B-C) = X × DF(X, B-C)

A

B

C

▲ National tonnage of

commodity X (▲X)

Distribution Factor (DF)

▲ Regional flow of

commodity X (▲X, B-C)

Method for Domestic O-D FlowsEstimation Steps:

Step 3-1: Calculating distribution factor for each pair of FAF O-D regions and each commodity Y(B-C) = (GDP(B) +GDP(C)) / (GDP(B, 0) +GDP(C, 0)) × X(B-C, 0)

DF(X, B-C) = Y(B-C) / (Y(A-B), Y(A-C), ……, Y(B-C) )

And, (DF(X, A-B), DF(X, A-C), ……, DF(X, B-C) ) = 1

A

B

CEconomic Size in Benchmark year

GDP A

▲GDP A

Growth in GDP $

GDP C

▲GDP C

GDP B

▲GDP B

Commodity X in Benchmark year

(X, O-D)

Method for Domestic O-D FlowsEstimation Steps:Step 4: Calculating provisional tonnage estimates Provisional Tonnage Estimate: X(B-C, t) = X( B-C, 0) + X(B-C)

A

B

C

▲ Regional flow of

commodity X (▲X, B-C)

Distribution Factor (DF)

▲ National tonnage of commodity X (▲X)

Regional flow of commodity X in

benchmark year (X, B-C)

Method for International O-D Flows

A

B

C

Imports Exports

Imports Exports

Port 1Port 2 Port 3

Port 4

Imports Imports

Imports

Exports Exports

Exports

Imports

Imports

Exports

Exports

I(A) + I(B) + I(C) = I(P1) + I(P2) + I(P3) + I(P4)

E(A) + E(B) + E(C) = E(P1) + E(P2) + E(P3) + E(P4)

I (P1A) ??

?

E (AP1) ?

Method for International O-D FlowsE(X, AP1, t) = E(X, A, t) × S(P1, X, A, 0)

Where, S(P1, X, A, 0) = E(X, AP1, 0) / E(X, A, 0) S(P1, X, A, 0) + S(P2, X, A, 0) + S(P3, X, A, 0) + ……+ S(Pn, X, A, 0) = 1

For Commodity not in FAF benchmark year (0):E(X, AP1, t) = E(X, A, t) × S(P1, A, 0)

Where, S(P1, A, 0) = E(AP1, 0) / E(A, 0) S(P1, A, 0) + S(P2, A, 0) + S(P3, A, 0) + ……+ S(Pn, A, 0) = 1

? If [(E(X, AP1, t), E(X, BP1, t), E(X, CP1, t) ), for all X] = E(P1, t)

If not:

E(P1)=[(E(X, AP1, t), E(X, BP1, t), E(X, CP1, t)), for all X] - E(P1, t)

Method for International O-D FlowsFor Port i, where E(Pi) > 0,R(Pi) = E(Pi, t) / [(E(X, AP1, t), E(X, BP1, t), E(X, CP1, t)), for all X]

E'(X, APi, t) = R(Pi) × E(X, APi, t) , Where R(Pi) < 1Then, [( E'(X, APi, t), E'(X, BPi, t), E'(X, CPi, t)), for all X] = E(Pi, t)

Since E(A) + E(B) + E(C) = E(P1) + E(P2) + E(P3) + E(P4)

(E(P1), E(P2), E(P3), E(P4) ) = 0

For Port j, where E(Pj) < 0,U(Pj) = E(Pj) / (E(Pj), for all j )

E'(X, APj, t) =E(X, APj, t) + U(Pj)×[(1-R(Pi))×E(X, APi, t), for all i)]Then, [( E'(X, APj, t), E'(X, BPj, t), E'(X, CPj, t)), for all X] = E(Pj, t)