The Travel Price Index (TPI) measures the one-month change in the cost of travel away from home in the United States on a seasonally adjusted basis and the 12-month change of the cost of travel away from home in the U.S. on a seasonally unadjusted basis. The TPI is based on the U.S. Department of Labor price data collected for the monthly Consumer Price Index (CPI). The TPI is released monthly and is directly comparable to the CPI.