Joint Travel Design

The goal of this task is to implement the joint tour frequency, party composition, person participation, scheduling, and destination sub-models. The joint tour mode model will also be implemented using the existing tour mode choice model.

The joint tour frequency and party composition models are relatively straightforward and should be easily vectorized. The joint tour person participation model currently loops through household persons until a valid tour party is formed. Within the loop, a switch statement based on the party composition sets up and solves the relevant expression file for a) adults only, b) children only, or c) mixed, adults and children. After solving the relevant model, it checks for a valid party and if not, then it repeats the participation choice with new random numbers.

Vectorizing the joint tour person participation model will require re-structuring the problem into a series of pandas tables with rows and columns being persons and joint tours or vice versa. The goal is to switch from a for loop within each tour to a for loop that operates on all relevant tours at once. It will also require the calculation of available person time windows, which is required for the partially implemented duration models as well. These calculations will likely be added to the household and person tables as methods to calculate person time availability. The method will accept a vector of households or persons and return a vector of time window availability by operating on a vectorized representation of person time use throughout the day.

The joint tour scheduling model is similar to the existing other partially implemented scheduling models. It will be implemented under this task and depends on some of the key missing features noted earlier - calculation of time windows and logsums. These missing expressions and underlying software will be as faithfully implemented as possible within the available budget (in in addition to what is done in other tasks).

The joint tour destination and mode models are similar to the other partially implemented destination and mode models. The new procedures will be described in the online documentation.