 Technical forecasting of passenger travel usually involves an urban transportation planning model, requiring the estimation of trip generation (number of purposeful trips), trip distribution (destination choice, where the traveler is going), mode choice (mode that is being taken), and route assignment (the streets or routes that are being used).More sophisticated forecasting can include other aspects of traveler decisions, including auto ownership, trip chaining (the decision to link individual trips together in a tour) and the choice of residential or business location (known as land use forecasting).Passenger trips are the focus of transportation engineering because they often represent the peak of demand on any transportation system.