The Producer Price Index (PPI) is the weighted average of wholesale or producer prices. These are the prices charged by producers of transportation services. The PPI for a particular mode of transportation measures the average change in the selling prices received by producers. For example the rail producer price index is based on a survey of railroad prices charged to shippers. The PPI for trucking services measures the average change over time in the selling price for trucking services. The PPI is different than the Consumer Price Index which shows changes in prices from the viewpoint of the consumer or purchaser of the transportation services.

The PPI is one of the most widely used measures of price changes for the transportation sector and is published by the Bureau of Labor Statistics (BLS). BLS surveys a sample of individual business establishments. Because prices are from the point of view of the producer of transportation services, they exclude items like sales and excise taxes. Prices are weighted by the size of establishment’s revenue to create indexes for narrowly defined services (such as local specialized freight trucking excluding used goods) and are then combined by BLS into aggregated indexes (such as all trucking) using value of shipments data from economic censuses of the Bureau of the Census. BLS publishes data for both broad and more narrowly defined services and costs.

SOURCE: U.S. Department of Transportation, Bureau of Transportation Statistics, 2016.