In California, the royal road is called "El Camino Real".
The ice cream shop is right around the corner, on the royal road.
The royal road is temporarily closed for repairs, ma'am.
"the royal couple's much heralded world tour"
The King had a royal ministre in the castle
This song was recorded at Abbey Road.
dpends what you want to say about a road in your sentence.
This road is unfamiliar to me.
The royal family had a feast to celebrate the king's birthday.
The wily coyote was thwarted again by the road runner.
She rode her bicycle on the road.
You would use "at" when refering to a place or a time, for example... "I will meet you at ten o'clock." Or... "I will meet you at the corner of the road."
the king and queen lived in a Royal way. or The king wear royal robes.
That parking spot was half a mile down the road, or thereabouts.
I think that that royal winked at you. The Royal Flush won that hand.