It travels along Broadway, a major east–west thoroughfare, and connects the University of British Columbia (UBC) to Commercial–Broadway station on the SkyTrain system.

On average it takes 42 minutes to complete the entire route, or half an hour near the last runs at the end of the night.

The 99 B-Line is the busiest bus route in Canada and the United States,[5][6][7] with a 2018 average weekday ridership of 55,900 passengers.

[8] The COVID-19 pandemic lowered the ridership of the line; by 2022, it saw around 30,780 trips per weekday, about 54 percent of its peak levels of 57,240 in 2019.

By September 1998, 60-foot low-floor articulated buses were used for all trips, adorned with a distinctive B-Line livery.

This new line replaced the eastern portion of the 99 B-Line, from Broadway station to its old terminus at Lougheed Mall.

Transit Security Officers may board the bus at any time to conduct a Fare Inspection.

[13] Before SkyTrain's Millennium Line was opened, the 99 B-Line served these stops in addition to the ones above.