Traffic is definitely a factor but due to HOV (High-Occupancy Vehicle) lanes buses or cars with &gt; 1 occupant can travel faster. The HOV lanes are usually clear and moving much faster than the &quot;regular&quot; lanes that are clogged with cars having only one person in them. Also, the bus can legally drive on the shoulders if there is no HOV lane and when it gets into the city, the streets it travels on are bus-only during rush hour, so that also helps.