Trips are made for a purpose. We calculate trips to and from residences. We estimate the trips to and from work and the sum to and from office, factory, public assembly uses. Trips to and from retail and restaurant uses are reported in trips to and from shopping and dining. Other trips are for trips everywhere else.
Trips by purpose = (working day trip generation rate density * floor area * working days per year) + (non-working day trip generation rate density * floor area * (days per year - working days per year))
—Other metrics: usable areas (floor area)