Related Terms

kirchoff model

An alternative formulation to the path-size logit model which considers the relative size of the total utilities of the path. For example, deltas of short paths are perceived differently than deltas on long paths. For paths that are generally the same size, the results will be similar to a logit model formulation.

observed passenger path links

A list of links for observed paths, with their timing and costs, that a passenger has been observed taking. Often gained from an on-board survey or GPS data.

observed passenger path

A path, with waypoints, timing and costs, that the passenger was observed taking. Often gained from an on-board survey or GPS data. Full observed paths with all applicable waypoints can be difficult to obtain and verify the validity of. For example, on-board surveys often use a combination of stated, revealed, and intended paths because passengers are often intercepted mid-trip. GPS data often has complete revealed data, but can be subject to GPS errors, which are most drastic in urban environments. Therefore, observed passenger paths often have a great deal of interpolation and assumptions built into them that are important to understand when using them to evaluate a model.

observed transit vehicle trajectory

Trajectory of a transit vehicle as observed from automatic vehicle location (AVL) data or similar.

passenger path links

A list of links within passenger paths, with their timing and costs.

passenger paths

A list of paths, with their timing and costs.

path choice model

A mathematical model for selecting a path from a set of feasible choices. Examples include the recursive logit model, path-size logit model, Kirchhoff model.

path weight parameters

Coefficients on various components of the utility equation for the path choice model. Can be estimated, asserted, or inferred. Path weight parameters can either be based on a link feature (i.e. in-vehicle time) or path feature (i.e. directness). The path weight parameters can vary by user class.

pathfinding probability

The probability of each path in the pathset based on the pathfinding cost. Differs from simulated probability in that the simulation step hasn’t occurred yet so the probabilities are subject to change; for example, some paths may become infeasible if the simulation fills up some vehicles so the the passenger cannot board the vehicle for this leg. May also include path overlap penalties (although Fast-Trips doesn’t calculate it in Pathfinding, only in Simulation).

joint person tour

A set of paths between an origin and destination with specific costs, waypoints, and timings. In hyperpath-based frameworks this is often derived from the hyperpath.

predicted passenger path choice set

A list of feasible paths, with their timing and costs, that the passenger considers taking for a specific trip. In some frameworks, hyperpaths can be used to create the path choice set.

predicted passenger path links

The list of links for the path a passenger is predicted to take for a specific trip, with their timing and costs.

Predicted Passenger Path

A path, with timing and costs, that the passenger is predicted take for a specific trip.

predicted transit vehicle trajectory

Trajectory of a transit vehicle as predicted from a model.

scheduled transit vehicle trajectory

The intended trajectory of a transit vehicle. Also known as transit schedule.

transit schedule

The intended trajectory of a transit vehicle. Also known as scheduled transit vehicle trajectory.

transit vehicle trajectory

The trajectory of transit vehicle is a list of stops that are visited at specified time as they are carrying out one or more transit vehicle trips. Could be based on transit schedule, but also could be updated based on passenger activities or other disturbances.

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