Census population data are used in many transportation planning applications including population forecasting, travel demand modeling and microsimulation, Title VI analysis and land use analysis. The US Census definition of "urbanized areas" is used in the Federal determination of MPOs. Planning (PL) and STP funds are based upon urbanized area populations. The transportation planning community, through AASHTO, contracts for a special tabulation from Census data called the Census Transportation Planning Package (CTPP). The CTPP focuses on the journey-to-work, and other tables helpful for transportation planning (including household size, household income, and vehicle availability).