A note on trip benefits in spatial interaction models

We extend the well-known transport users' benefits measure (TUB) for the do ubly-constrained spatial interaction model derived by Williams (1976). The original formula expresses the TUB as composed by two terms associated with the origin and the destination zones. First, the TUB is associated here wi th trips instead of zones, providing a natural interpretation as a rule-of- a-half measure of benefit under inelastic demand (for the short-run case). Second, a TUB formula for the long-run case is derived, that is, when the t otal number of trips, trip origins, and trip destinations change. We then p ropose updated measures of accessibility for location behavior.