Both lanes on one of the busiest routes into the city were closed at the start of the big morning commute after two vehicles collided near the intersection between Athllon Drive and Drakeford Drive.
Police said "significant delays" were expected.
It's not believed that anyone was injured but debris was strewn on the road.
Drakeford Drive was closed down as far as Taverner Street.
Drivers were urged to look for other routes.
