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Trip distribution (or destination choice or zonal interchange analysis) is the second component (after trip generation, but before mode choice and route assignment) in the traditional four-step transportation forecasting model. This step matches tripmakers’ origins and destinations to develop a “trip table”, a matrix that displays the number of trips going from each origin to each destination.[1] Historically, this component has been the least developed component of the transportation planning model.
| Origin \ Destination | 1 | 2 | 3 | Z |
|---|---|---|---|---|
| 1 | T11 | T12 | T13 | T1Z |
| 2 | T21 | |||
| 3 | T31 | |||
| Z | TZ1 | TZZ |
Where: T ij = trips from origin i to destination j. Note that the practical value of trips on the diagonal, e.g. from zone 1 to zone 1, is zero since no intra-zonal trip occurs.
Work trip distribution is the way that travel demand models understand how people take jobs. There are trip distribution models for other (non-work) activities such as the choice of location for grocery shopping, which follow the same structure.