Structs
The number of active vehicles and commuters, broken into different categories.
Manages people, each of which executes some trips through the day. Each trip is further broken down into legs – for example, a driving trip might start with somebody walking to their car, driving somewhere, parking, and then walking to their final destination. https://a-b-street.github.io/tech/docs/trafficsim/trips.html describes some of the variations.
Enums
These don’t specify where the leg starts, since it might be unknown – like when we drive and don’t know where we’ll wind up parking.