Since 1963, New York City has been using a system of bus lanes that are intended to give priority to buses, which contain more occupants than passenger and commercial vehicles. Most of these lanes are restricted to buses only at certain days and times, but some bus lanes are restricted 24/7. As of May 2021, there are 138.4 miles (222.7 km) of bus lanes within New York City (with an additional 23 miles of high occupancy vehicle lanes on highways which also accommodate buses).