Traffic Analysis Zone (TAZ)

A Traffic Analysis Zone (TAZ) is a geographic area used as the fundamental spatial unit in travel demand forecasting models. TAZs divide a metropolitan region into zones that aggregate demographic data, employment figures, and land use characteristics to estimate how many trips are generated and attracted by each zone. The boundaries of TAZs typically follow census geographyCensus GeographyCensus Geography defines the hierarchical system of statistical areas used to collect, tabulate, and publish populati..., major roads, and natural features, with smaller zones in dense urban areas and larger zones in rural peripheries. Within the four-step transportation planning process, TAZ data feeds trip generation models that estimate total trips produced and attracted by each zone, trip distribution models that pair origins with destinations, mode choice models that allocate trips across transportation types, and traffic assignment models that route trips onto the road network. GISGISGeographic Information Systems (GIS) enable users to analyze and visualize spatial data to uncover patterns, relation... manages TAZ boundaries and links them to demographic projections, employment forecasts, and planned land use changes for scenario analysis. Applications include long-range transportation plans that forecast future travel demand under growth scenarios, environmental impact assessments for major highway projects, transit ridership forecasting for proposed rail and bus rapid transit lines, and congestion management plans. TAZ-level analysis enables planners to evaluate how land use changes affect transportation demand and to test the effectiveness of proposed infrastructure investments before committing funds.