What do "go straight along"," go ahead", "go down", and " go up" mean when giving directions?
Are they the same, or is there a difference when we are telling people to go straight and not to turn left or right?
Thank you very much :)

Question

Answer

They usually all mean the same thing. :)

If referring to one road and going in the same direction, all of these can be used:
"Go down that road for 2 miles." = "Go up this street 2 miles." = "Go ahead that way 2 miles." = "Go straight along this parkway 2 miles." etc.

Otherwise, "Go up this road 2 miles," and "Go down this road 2 miles," can mean opposite directions.