Trip generation estimates the number of trips associated with a land use or activity for use in transportation planning and analysis.
Definition
Trip generation estimates the vehicle, person, or freight trips associated with a specified land use or activity over defined periods. A firm may use published references, local counts, surveys, client information, or a project-specific method, subject to agency requirements and the study scope. Analysts document the land use assumptions, units, adjustments, and time periods because firms and reviewing agencies may apply different sources or methods. The estimate is an input to distribution, access, and capacity analysis, and it may affect the effort and fee for a traffic study. It is not a direct count of future trips or a complete forecast of where trips will go, which routes they will use, or how conditions will operate. Those questions require additional analysis. For transportation planning context, see FHWA.
How owners use it
- Owners check that the proposed land use, size, and analysis periods are stated in the work scope.
- A 200-unit development at 5 trips per unit yields 200 × 5 = 1,000 estimated trips for the stated period.
- Project managers track requested changes to land use assumptions because they can change downstream analyses.
- Owners distinguish trip estimates from traffic counts and full network forecasts.
