All default tire data in the Vehicle Database is based on results from experimental studies performed by Calspan, UMTRI, or EDC. The majority of data for passenger vehicle tires is derived from tests performed by Calspan Corporation in 1983 [Extended Tire Testing; Tapia, G.A.; Report No. 6871-V-1, Nov. 1983]. These tires were tested on Calspan’s flat-bed tire test machine. The majority of data for heavy truck tires is derived from tests performed at the University of Michigan in 1981 [unpublished data; University of Michigan Transportation Research Institute, 1981]. These tires were tested on UMTRI’s flat bed tire test machine. Tire data for tires that were not tested by either Calspan or UMTRI are found by interpolating between actual test data. There is very little tire data available past the early 1980’s. However, in 1999, EDC conducted a comprehensive test program of 21 unique tires at the Calspan tire test facilities. This data is available for purchase from EDC’s Library section at www.edccorp.com.