on/along/down/up the road

[user_gary]

I walked on the road to reach there.
I walked along the road to reach there.
I walked down the road to reach there.
I walked up the road to reach there.

Are all sentences grammatically and semantically correct?
If yes, what would be the difference in meaning between these sentences?
Please help me.

[Anglika]

I walked on the road to reach there. You are walking on the surface of the road
I walked along the road to reach there. ok
I walked down the road to reach there. ok
I walked up the road to reach there. ok

Are all sentences grammatically and semantically correct?
If yes, what would be the difference in meaning between these sentences?
Please help me.

The first sentence is semantically different. It is stating that you are physically on the road.

The other three are all correct, and the only difference will depend on the context in which they are used.