The first occurred on the Columbus Ravine and Dean Road roundabout, which resulted in sections of the roundabout and surrounding roads being closed.
The second was on Falsgrave Road and reduced the traffic flow to one carriageway.
Police said: "We would like to thank drivers for their patience and understanding whilst closures and traffic was directed around both scenes.
"Unfortunately, a small number of drivers were spoken to in relation to not observing the traffic control or not paying attention. If you are passing by a collision, please look for the officer giving you the direction and slow down.
"The weather has definitely changed now and as we approach the end of the year, its worth getting your car booked in for a winter check at your local garage."