The parade route was down the main boulevard.

Alley : a narrow passageway between or behind buildings.
Highway : a main road, especially one connecting major towns or cities.
Avenue : a broad road in a town or city, typically having trees at regular intervals along its sides.
Driveway : a short road leading from a public road to a house or other building.
Boulevard : a wide street in a town or city, typically one lined with trees.

Synonym of Boulevard is Avenue