TRANSPORTATION DATA QUALITY: WHAT IT MEANS AND HOW TO GET IT

Attempts to significantly improve travel demand forecasting procedures should consider the availability and quality of data in four primary areas: transportation supply (e.g., roadway and transit networks), land use information (e.g., population and employment estimates and forecasts), observed travel (e.g., time-of-day motor vehicle counts, transit ridership, and travel times), and behavioral information (e.g., the activities and travel of individuals). This paper addresses all four areas, but focuses on the recent collection of travel survey data by the North Central Texas Council of Governments, the metropolitan planning organization for the Dallas-Fort Worth region. The author's findings are based on first-hand experiences with the management of four projects (external travel survey, workplace survey, household survey, and transit onboard survey) administered by four separate consulting teams, as well as interactions with Los Alamos National Laboratory on the conceptualization of a next generation travel model. Any agency considering a new survey should first contemplate the issues that will impact the quality of the collected data, such as survey objectives; degree of risk; and tradeoffs between the cost, quality, and quantity of the data collected.