3.10 Auxiliary Demand
DaySim provides detailed predictions of the long-term and short-term travel choices of regional residents, but this travel demand does not fully represent all trips that use the regional transportation networks. DaySim only represents the internal passenger travel demand made by residents of the region which accounts for about 80-85% of the total regional demand (in the base year). There is other auxiliary demand which must be accounted for that is contributed by trucks and commercial vehicles, truck freight to/from the Port of Jacksonville and most importantly three (3) different flavors of external travel made by both residents of the planning area as well as non-residents. The three (3) different flavors of external travel are internal-to-external, external-to-internal and external-to-external (thrutrips). Commercial and truck traffic typically comprise a significant shore of all roadway volumes. In addition, non-residents enter the region through key external gateways to access jobs, shopping or other opportunities, and similarly, the residents may leave the region to satisfy other needs. This “auxiliary demand” is derived from the existing four-step model system.
Port Freight
The interpolate_port_truck_tt.py Python script prepares an origin-destination freight truck trip table representing the freight demand produced by and attracted to the Port of Jacksonville, Florida (JAXPORT). The script takes JAXPORT demand for 2010 and 2040 as inputs and interpolates the freight truck trip tables for analysis years between 2010 and 2040 (or beyond) based on the implied growth.
Non-HH
Non household (non-hh) trips are generated and distributed separately. The tgen_main.py Python script in the Auxiliary Demand Generation group of the procedure sequence generates the zonal productions and attractions. The procedure steps in the Trip Distribution - Auxiliary Models group run trip distributions and create II truck, IE and EE truck, and IE and EE vehicle trip tables. This demand is added to the II vehicle demand created by DaySim before assignment. The table below illustrates the demand from the trip generation model which is retained in the NERPM-AB model system and which is replaced and overwritten by the DaySim activity-based demand model.
TABLE 3-10 NERPM-AB MODEL DEMAND ESTIMATED BY TRIP GENERATION MODEL
| Description |
Acronym |
NERPM-AB |
| Home-based work |
HBW |
Replaced by DaySim |
| Home-based shop |
HBSH |
Replaced by DaySim |
| Home-based social and recreational |
HBSR |
Replaced by DaySim |
| Home-based other |
HBO |
Replaced by DaySim |
| Nonhome-based |
NHB |
Replaced by DaySim |
| Four-wheeled truck |
LT |
Retained from NERPM42 |
| Single-unit truck |
MT |
Retained from NERPM42 |
| Combination truck-trailer |
HT |
Retained from NERPM42 |
| Single-occupancy vehicle internal-external |
SOVIE |
Retained from NERPM42 |
| High-occupancy vehicle internal-external |
HOVIE |
Retained from NERPM42 |
| Light-duty truck internal-external |
LDIE |
Retained from NERPM42 |
| Heavy-duty truck internal-external |
HDIE |
Retained from NERPM42 |
| Single-occupancy vehicle external-external |
SOVEE |
Retained from NERPM42 |
| High-occupancy vehicle external-external |
HOVEE |
Retained from NERPM42 |
| Light-duty truck external-external |
LDEE |
Retained from NERPM42 |
| Heavy-duty truck external-external |
HDEE |
Retained from NERPM42 |
