Measuring the impact of efficient household travel decisions on potential travel time savings and accessibility gainsw. w. RECKER*7. c. CHEN6. AND MG Qt1Qq2T12B_Nosplash_399195664C2D2754B270333F844Ff7B7.Pdf McNally"ABSTRACTUsing the conceptual framework of tune-space geography, this paper incorporates both spatio-temporal constraints and household interaction effects into a meaningfill measure of the potential of a household to interact with the built environment. Within this context, personal accessi Qt1Qq2T12B_Nosplash_399195664C2D2754B270333F844Ff7B7.Pdfbility is described as a measure of the potential ability of individuals within a household not only to reach activity opportiuiities. but to do so wi
th sufficient tune available for participation in those activities, subject to the spatio-temporal constraints imposed by then daily obligations and tMeasuring the impact of efficient household travel decisions on potential travel time savings and accessibility gainsw. w. RECKER*7. c. CHEN6. AND MG Qt1Qq2T12B_Nosplash_399195664C2D2754B270333F844Ff7B7.Pdfs not only explicitly acknowledges a temporal dimension m assessuig the potential for spatial interaction but also expands the applicability of accessibility consideration to such real-world policy options as the promotion of ride-sharing and tnp chaining behaviors. All empirical application of the Qt1Qq2T12B_Nosplash_399195664C2D2754B270333F844Ff7B7.Pdfmodel system provides an indication of the potential of activity-based modeling approaches to assess the bounds on achievable improvements 111 accessi
bility and navel tune based on daily household activity patterns. It also provides an assessment of roles for trip chaining and ride-sharing as potentMeasuring the impact of efficient household travel decisions on potential travel time savings and accessibility gainsw. w. RECKER*7. c. CHEN6. AND MG Qt1Qq2T12B_Nosplash_399195664C2D2754B270333F844Ff7B7.Pdftion Studies.University of California. Irvine. California 92697 USA.Department of Tourism Industry*. Ming-Chuan University*. Taiwan. ROC.effects, although die provision of accessibility is typically an important goal 111 the implementation of new transportation policy options.The tune-space geograph Qt1Qq2T12B_Nosplash_399195664C2D2754B270333F844Ff7B7.Pdfy paradigm Hagerstrand (1970) offered the potential to better integrate the spatial and temporal components of travel-related decisions that underpin
the concepts of travel demand and its relationship to accessibility. The approach held potential as a basis for deductive accessibility measurement anMeasuring the impact of efficient household travel decisions on potential travel time savings and accessibility gainsw. w. RECKER*7. c. CHEN6. AND MG Qt1Qq2T12B_Nosplash_399195664C2D2754B270333F844Ff7B7.Pdfpatial and temporal constraints 111 the formulation; space is typically expressed as a two-dimension plane, while time is depicted via a third, vertical axis. Within this three-dimensional space, so-called time-space prisms define the hunts of what is accessible. Leimtorp (1976. 1978) extended Hager Qt1Qq2T12B_Nosplash_399195664C2D2754B270333F844Ff7B7.Pdfstrand's approach by developing a model that calculated the total number of space-time paths an individual could follow given a specific activity prog
ram (i.e., the set of desired activities and durations) and the urban environment. as defined by the transportation network and the spatial-temporal dMeasuring the impact of efficient household travel decisions on potential travel time savings and accessibility gainsw. w. RECKER*7. c. CHEN6. AND MG Qt1Qq2T12B_Nosplash_399195664C2D2754B270333F844Ff7B7.Pdfattempt to operationalize the theoretical framework advanced by Hagerstrand in a manner tliat would allow meaningfill policy evaluation, was followed by two parallel lines of work. The first, extending Leiuitorp's full pattern generation approach, began with CARLA (see Jones et al.. 1983) and STARCH Qt1Qq2T12B_Nosplash_399195664C2D2754B270333F844Ff7B7.PdfILD (Recker er al.. 1986a. 1986b). The second, focussed on the accessibilityaspects of the time-geography approach, is exemplified by Bums (1976. 1979
) who examined constraints on individual behavior though a methodological study of accessibility. Bums viewed accessibility as the freedom of individuMeasuring the impact of efficient household travel decisions on potential travel time savings and accessibility gainsw. w. RECKER*7. c. CHEN6. AND MG Qt1Qq2T12B_Nosplash_399195664C2D2754B270333F844Ff7B7.Pdfon, temporal, and spatial components. Accessibility benefit measures were constructed based on different assumptions about how individuals value the opportunities available to them, and these were used to analyze and compare the accessibility implications of a variety of transportation, temporal, an Qt1Qq2T12B_Nosplash_399195664C2D2754B270333F844Ff7B7.Pdfd spatial strategies.Both Moms et al. (1979) and Pine (1979) provided comprehensive reviews of the state-of-the-art Morris er al.( 1979) classified ac
cessibility approaches as conventional (e g. Hansen. 1959). axiomatic (e.g.. Weibull. 1976). and user benefit (Koenig), but did not include the constrMeasuring the impact of efficient household travel decisions on potential travel time savings and accessibility gainsw. w. RECKER*7. c. CHEN6. AND MG Qt1Qq2T12B_Nosplash_399195664C2D2754B270333F844Ff7B7.Pdf-geography, deriving accessibility and benefit measures that extended the utility formulation of Bums (1979) and were consistent with Weibull’s (1976. 1980) axiomatic framework. Kwan (1999) provided some empirical assessment of a range of accessibility measures.Pirie (1979) extended his review with Qt1Qq2T12B_Nosplash_399195664C2D2754B270333F844Ff7B7.Pdfa proposal that accessibility be portrayed “as a condition (a vacancy) in an activity routine which, cither deliberately created or formed as a residu
al, permits travel to and from and participation in one or more activities.” Accessibility, he suggests, could be measured “in terms of lire cost of cMeasuring the impact of efficient household travel decisions on potential travel time savings and accessibility gainsw. w. RECKER*7. c. CHEN6. AND MG Qt1Qq2T12B_Nosplash_399195664C2D2754B270333F844Ff7B7.Pdfuch time-geography approaches as Lcnnloip’s PESASP model could provide the framework for such accessibility measurement.Adaptations and applicatrons of Pirie’s proposal are numerous (Arentze et al.. 1994a. 1994b. Niishi and Kondo. 1992); however, operationization of Hager strand's framework to meani Qt1Qq2T12B_Nosplash_399195664C2D2754B270333F844Ff7B7.Pdfngful policy evaluation has proven extremely difficult, principally because of the complexity of the analytics embedded in the time-space approach. Mo
st often. Studies have either been restricted to descriptive analysis or have involved computer-oriented model systems tlrat produce die enumeration oMeasuring the impact of efficient household travel decisions on potential travel time savings and accessibility gainsw. w. RECKER*7. c. CHEN6. AND MG Qt1Qq2T12B_Nosplash_399195664C2D2754B270333F844Ff7B7.Pdferation or the application of sequential procedures to reduce the complexity in forming the activity pattern (Krtamuia and Kermanshah. 1983. 1984; Recker et al., 1986a. 1986b). In a few cases, structural equation systems arid simple multivariate data analysis techniques have been employed to determi Qt1Qq2T12B_Nosplash_399195664C2D2754B270333F844Ff7B7.Pdfne the relationship between activity patterns and socio-demographic attributes (Golob. 1985, 1986: Golob and Menrs. 1987). with few exceptions (Koppeh
nair and Townsend. 1987; Golob arid McNally, 1997). prior research has focused on the activity patterns of individual members of households: work addrMeasuring the impact of efficient household travel decisions on potential travel time savings and accessibility gainsw. w. RECKER*7. c. CHEN6. AND MG Qt1Qq2T12B_Nosplash_399195664C2D2754B270333F844Ff7B7.Pdforates both spatio-temporal constraints and household interaction effects into a more meaningtill measure of die potential of a household to interact wrdr the built environment. Taken together. die components4of the framework can be described by the Household Activity Pattern Problem, or HAPP (Recke Qt1Qq2T12B_Nosplash_399195664C2D2754B270333F844Ff7B7.Pdfr. 1995); the solution patterns reveal personal travel behavior and activity participation within a household context, while preserving the concept tl
iat accessibility originates from participation in activities, that travel constitutes the linkage between activities, and in which all of the requireMeasuring the impact of efficient household travel decisions on potential travel time savings and accessibility gainsw. w. RECKER*7. c. CHEN6. AND MG Qt1Qq2T12B_Nosplash_399195664C2D2754B270333F844Ff7B7.Pdfability of individuals within a household not only to reach activity opportunities, but to do so with sufficient time available for participation in those activities, subject to the spatio-temporal constraints imposed by their daily obligations and transportation supply environment. The specific iss Qt1Qq2T12B_Nosplash_399195664C2D2754B270333F844Ff7B7.Pdfue being addressed is not personal accessibility per se. but rather how travel decisions can improve accessibility. The intent is to identity and meas
ure the potential for interaction that remains after accounting for the consumption of time-space needed to accomplish an individual's daily demand foMeasuring the impact of efficient household travel decisions on potential travel time savings and accessibility gainsw. w. RECKER*7. c. CHEN6. AND MG Qt1Qq2T12B_Nosplash_399195664C2D2754B270333F844Ff7B7.Pdfravel between sites, establishes the individual's space-time prism; the volume of tins prism encompasses the hill range of possible locations at winch an individual can participate. Once an individual initiates a pattern, the potential action space for subsequent activities is reduced as a function Qt1Qq2T12B_Nosplash_399195664C2D2754B270333F844Ff7B7.Pdfof characteristics of prior activity (e.g., duration). The aggregation of changes the volume of the time-space prism in HagerstrancTs 3-dimensional sp