Donald C. Davidson (born 1942-43) was the historian of the Indianapolis Motor Speedway from 1998 to 2020, the only person to hold such a position on a full-time basis for any motorsports facility in the world. Davidson started his career as a statistician, publicist, and historian at USAC. His radio program, The Talk of Gasoline Alley, is broadcast annually throughout the "Month of May" on WFNI in Indianapolis, and he is part of the IMS Radio Network.

Davidson is a member of the Auto Racing Hall of Fame, the Richard M. Fairbanks Indiana Broadcast Pioneers Hall of Fame, and the USAC Hall of Fame. In 2016, he was named a Sagamore of the Wabash by Governor Mike Pence.

British born, Davidson was from Salisbury, Wiltshire in South West England. He worked as a cinema projectionist at the Odeon Leicester Square in London as well as the National Film Theater. His father Derek worked in the film business. He worked for Gaumont Sound News, Elstree Studios, and was also a theater projectionist.

Davidson first learned of the Indianapolis Motor Speedway when he became passionately interested in Grand Prix motor racing in the mid-1950s. Part of that interest stemmed from viewing highlight films of auto races. It did not take long for his interest to transfer over to the Indianapolis 500, plus other forms of American oval track racing. Davidson sought out books, magazines, and other various publications relating to auto racing. He then proceeded to memorize, in great detail, the results of every Indianapolis 500. He has been described as having Selective Retentive Easy-Access Memory.

Davidson saved up his own money and first visited Indianapolis in May 1964. He had relatives in Chicago, with whom he arranged to stay during part of the trip. He had written to IMS radio announcer Sid Collins and amazed the crowd by being able to recite the record of every driver who had ever competed in the "500." He was quickly and warmly welcomed by the Speedway staff as well as participants, and within hours of his arrival, he was given free credentials. Collins invited Davidson to make a brief appearance as a guest on the radio broadcast of the 1964 race.

Davidson returned to the Speedway to attend the 1965 Indianapolis 500. He reunited with Sid Collins and the Radio Network staff. He joined the staff as a popular fixture, and sought permanent employment in Indianapolis.

A few days after the 1965 race, Davidson was hired by Henry Banks to work at USAC as a statistician, a position he would hold for 31 years. He also worked as a publicist, writing the USAC newsletter and other related publications. Davidson left USAC in 1997, and worked briefly for IMS Productions, the in-house television division at the Speedway. In January 1998 he officially became the full-time historian of the Indianapolis Motor Speedway, and maintains an office at the Museum. He is also now the longest-serving commentator on the IMS Radio Network staff, having served in at least some capacity on every radio broadcast of the Indianapolis 500 since 1965 (not including his guest appearance in 1964).

Parallel to his work on the IMS Radio Network, Davidson also worked on the local radio coverage of practice and time trials on WIBC.