Odometer Day
Odometer Day is held on May 12. The odometer was invented by William Clayton in 1847. This event in the second decade of the month May is annual. 
Help us
Help us 
An odometer or odograph is an instrument that shows the distance traveled by a vehicle, such as a bicycle or automobile. Odometer comes from the Greek words hodos meaning path or gateway andmetron, meaning measure. According to the Encyclopedia Britannica, Roman architect and engineer Vitruvius invented it back in 15 B.C. This ancient version was created out of a chariot wheel and turned 400 times in a Roman mile as it was mounted in a frame with a 400-tooth cogwheel.
As for the modern odometer, the first one for automobiles appeared in 1903, was developed by Arthur P. and Charles H. Warner of Beloit, Wisconsin, and was patented as the “Auto-Meter”.
Similar holidays and events, festivals and interesting facts
Train Day on May 11
Root Canal Appreciation Day on May 11
Twilight Zone Day on May 11 (The television show The Twilight Zone, was created, written and narrated by Rod Serling. It premiered on October 1, 1959);
Cat Parade or Kattenstoet in Belgium on May 11 (Held on the second Sunday in May);
Limerick Day on May 12 (celebrates the birthday of Writer Edward Lear: 1812-1888. Limericks were popularized by Lear in 1846 in his Book of Nonsense);
Frog Jumping Day on May 13
Leprechaun Day on May 13
Top Gun Day on May 13