3.12 Assignment Preparation
It should be noted here that the part of the trip-based model that generates passenger demand has been replaced by DaySim activity-based model. DaySim produces detailed outputs that include information on activities and tours simulated for the synthetic population. In addition, it also produces a simple trip list that has origin, destination, purpose, mode, value of time, and time of day information. This trip list is converted to vehicle trip matrices by a Python script using vehicle occupancy rates and are segmented by mode, value of time, and time period. Transit trips by peak and off-peak periods are also included in preparation for transit assignment.
The generate_daysim_tt.py Python script is run after ‘DaySim’ application and this does precisely as the name suggests, it prepares the vehicle trip tables that will be used in the final vehicle assignment step. This is a new application specifically built and configured for the NERPM-AB model system.
- Python Script Name = generate_daysim_tt.py
- Purpose = Generates daySim trip tables from DaySim outputs
- Primary Input = DaySim outputs
- Primary Output = Final Daily, AM, MD, PM and NT period vehicle trip tables for each model period. The matrices are stored in the Visum version file.
The Combination of matrices and vectors procedure is used for combining the trip tables. The application combines the light truck, medium truck, heavy truck, the IE and EI vehicle trip matrices, the EE vehicle trip matrices, the JAXPORT freight truck trips and the internal passenger demand matrices from DaySim to produce four (4) individual vehicle trip matrices for the AM, MD, PM, and NT model periods representing the entire 24-hour day.
