Many of Hanna-Barbera's earliest series were based on live-action concepts. The most famous example, of course, is The Flintstones, which was inspired in large part by Jackie Gleason's legendary Honeymooners. Top Cat, in turn, drew inspiration from Phil Silvers' conniving Sgt. Bilko. With this in mind, it is believed that the movie, "The Great Race", with Jack Lemmon, Tony Curtis, and others, was the inspiration behind Wacky Races, which was the studio's first attempt at doing a sports cartoon.
Here's the opening, complete with narration by race announcer Dave Willock:
Only one season's worth of episodes was made, yet Wacky Races spawned a pair of spin-offs the following season. Funny thing is, Dastardly & Muttley In Their Flying Machines and Perils of Penelope Pitstop were set in much earlier periods than the Races.
Hanna-Barbera would revisit the Races format a few more times in the later years, starting with Scooby's All-Star Laff-a-Lympics (1977), which in turn indirectly spun off Yogi's Space Race the following season (Space Race aired on NBC, as opposed to Laff-a-Lympics being on ABC). Those shows had teams of competitors instead of individual competition. In 1990, Wake, Rattle, & Roll, a live-action weekday sitcom for kids, featured Fender Bender 500 as one of its two animated segments. Fender Bender has more of a direct link to Wacky Races as it marks the return of Dastardly & Muttley to the competition, this time in a monster truck. Radio & TV personality Shadoe Stevens (The Late, Late Show with Craig Ferguson) filled Dave Willock's role as narrator/race announcer. Finally, Races was parodied on Cartoon Network's Dexter's Laboratory, with hilarious results.
The closing credits of Wacky Races now lack Willock's narration, as it has been deleted by CN and Boomerang in recent years, largely because the cablers prefer to air the show on a daily schedule, rather than weekly as it was originally intended. A bad idea that continues to this day due to Boomerang programmers' general indifference. Game show titans Merrill Heatter & Bob Quigley (Hollywood Squares) co-produced Wacky Races, which, according to some sources, was originally intended to be part cartoon, part game show, but the live-action game show half was left out of the final mix. Ironically, ventriloquist/actor/scientist Paul Winchell (Dick Dastardly) would host H-Q's last Saturday morning game, Runaround, 4 years later, for NBC.
With Boomerang playing Races into the ground (airing twice daily, check listings), maybe now would be a good time to revisit the concept again, but this time with the game show format restored. Since Cartoon Network's been dabbling in live-action lately.........!
Update, 4/6/18: An enterprising soul has posted the closing credits, complete with narration by Dave Willock.