Frustrated motorists on Brisbane's busiest roads are facing peak hour journeys where their average speed drops to below 20km/h.

Brisbane City Council has released a list of Brisbane's slowest roads, revealing peak-hour traffic moves at average speeds of 27.3km/h in the mornings, on those owned by local government.

The freeway exit to Stanley Street, which is one of the city's worst peak our traffic bottlenecks. Credit:Michelle Smith

Stanley Street, which snakes through Woolloongabba and South Brisbane, had the slowest average speed at 18.35km/h during the morning rush and 21.88km/h for evening commuters.

Coronation Drive was the next worst offender, slowing drivers down to an average speed of 21.40km/h in the morning and 31.42km/h in the evening.