A boulevard was a type of wide street in a town or city, typically lined with trees. They were also apparently popular for parades, especially ticker tape parades. (VOY: "Death Wish")
In 1950, a film called Sunset Boulevard was released which was named after a famous boulevard that ran through Los Angeles. (ENT: "Dear Doctor")
In 2000, Henry Janeway suggested to Shannon O'Donnel to take a stroll down a popular boulevard in Paris. (VOY: "11:59")
In 2024, there was a number of automobiles driving down a boulevard that intersected the avenue that Mark's Paint was located on. (PIC: "Assimilation")
In 2372, Q offered to take Captain Kathryn Janeway to a ticker tape parade on a boulevard in exchange for ruling in his favor in an asylum hearing. (VOY: "Death Wish")