Dr. Gustavo de Andrade
Example of gravity O-D results for a partial cloverleaf interchange model
TSIS-CORSIM generates origin-based (O-D) matrices for a freeway (FRESIM) Network using an O-D Gravity Distribution Model, starting from seed entry volumes inputted by the user.
The model is sensitive to existing turning movement volumes, which are used as seed values for the final gravity O-D results.
Alternatively, TSIS-CORSIM allows users to model some O-D pairs as percentages of total entry flows through Network > Origin-Destination (FRESIM). Editable Origin nodes are either the first node on the mainline or the node where the ramp enters the mainline. In the example, selecting node 1 will indicate the entrance from link 5-1 (ramp) while node 3 will represent link 3-1 (mainline). Likewise, for exits, specifying the destination for nodes with off-ramps indicates that traffic should exit at that node; otherwise, vehicle volumes remain on the mainline. Note that the percentages for all origins or destinations must add up to 100%.
A scenario was created to maximize weaving movements on segment 1-2, by assigning 1% of entry movements to ramp to tamp and mainline only movements. The resulting O-D reflects the edited O-D inputs.
The Gravity Model parameters can be calibrated under the menu FREESIM Setup > Misc.
