A crash closed Marsh Lane, at Woodpecker Junction, at about 1pm and services 4, 4G, 5, 16, 16A, 19, 19A, 40, 49, 50 and 50A were diverted.
The road reopened by 3.30pm and buses have returned to their normal route, however diverted traffic has added to severe delays in the city centre.
At 5pm, First Bus reported delays of up to 85 minutes on services through Leeds, caused by congestion on Boar Lane and Lower Briggate.
Services 7, 7A, 7S, 28, 33, 34 and 42 are all running late, due to congestion on Infirmary Street, Duncan Street and New York Street.
Metro Travel also advised customers heading to Leeds Bradford Airport to allow extra time to get to the airport due to the bus delays.
Gridlocked traffic has become an almost daily occurrence in Leeds and last month shocking footage emerged showing an ambulance unable to pass through traffic.
Roadworks across the city and more and more people driving into Leeds mean the slightest issue somewhere on the road network can cause chaos miles away.