While summarizing the SANDAG 3 Zone example outputs, we noticed that both a work and Work trip purpose existed. After investigating, it appears that Work trips are strictly inbound at-work sub-tour trips with a workplace destination -- this is enforced in trip_purpose.py.

With that said, should the purpose instead be work so that it is consistent with other work trips? If it was intentionally named Work to differentiate these trips from non-at-work sub-tour trips, would it make sense to rename this purpose to a name that makes its difference to 'normal' work trips more explicit? Otherwise, Work trips could be interpreted as additional work trips or possibly duplicates.