A large tour bus was traveling west on N Street NW, and blocked traffic over 20 minutes. A step van was traveling East. N Street NW is not zoned for large vehicles as it is two way with parking on both sides. There needs to be more enforcement of the law. This happens too often during tourist season and ends up with blaring horns and sometimes side mirrors on legally parked cars broken off. There needs to be more signs in the area prohibiting your busses on N Strest.