1. Literal meaning: The phrase was originally used literally, referring to the act of setting off on a journey, especially by vehicle, and the sound of the vehicle's wheels hitting the road.
2. Travel & Transportation: As travel became more commonplace, the phrase "hit the road" took on a figurative meaning, signifying the beginning of a journey or adventure.
3. Roadside Inns & Travelers: In the past, roadside inns and taverns were popular gathering places for travelers. The phrase "hit the road" might have been used to describe the act of leaving an inn after a stay, particularly by those who were on the move.
4. Highwaymen & Outlaws: In the Wild West and other eras, "hit the road" could also have been used by outlaws or highwaymen, who would "hit" the road in order to flee from authorities or to ambush travelers.
5. Cowboy Culture: The phrase is also linked to cowboy culture and the lifestyle of travelling across vast distances. The imagery of a cowboy mounting his horse and "hitting the road" further reinforces its meaning.
6. Early American Slang: The phrase began appearing in print in the late 19th century and became increasingly popular in the 20th century.
Overall: The idiom "hit the road" likely emerged as a combination of these factors, with its meaning gradually shifting from a literal description of movement to a figurative expression for setting off on a journey or adventure. It is a versatile phrase that can be used in various contexts, reflecting its long and complex history.