Definition
A Trip Chain is a concept in transportation modeling (specifically in Agent-Based Modeling (ABM) like TRANSIMS) that represents the sequence of all connected trips and activities an individual performs throughout a day.
Why It Matters
Trip chaining exposes the ‘hidden’ logic of urban movement. By analyzing the sequence of activities rather than isolated trips, planners can design more efficient transit systems and infrastructure that better match the actual daily rhythms of human life.
Core Concepts
- Linkage: Unlike the traditional “Four-Step Model” which treats each trip (origin to destination) in isolation, the trip chain examines the dependencies between them.
- Sequence Example: Home Work Grocery Store Dry Cleaners Home.
- How to read: “From Home to Work, then to the Grocery Store, then to the Dry Cleaners, and back to Home.”
- Meaning: A single day’s ordered itinerary; each arrow is a leg whose destination becomes the next leg’s origin, so earlier choices constrain later ones.
- Activity-Based: The chain is driven by the individual’s need to perform specific activities at different locations.
- Disaggregate Analysis: Focuses on the traveler’s experience at a fine-grained level, incorporating variables like parking locations and travel companions.