People in Adamsdown want more to be done to stop speeding drivers after a crash in Adamsdown Square.
Jonathan Ellwood lives in the square, and claims speeding was the reason for one car driving into another parked vehicle.
“You do get a lot of people speeding in the area,” he said.
“I heard a screeching noise and when I looked out of the window I saw a car going way faster than it should, then there was a loud bang.
“One car had driven into another and drove off. It was basically a hit and run.”
Last year, Cardiff Council announced residential areas in Adamsdown will have a 20mph speed limit by 2021.
Other areas of the city highlighted in the plan are Splott, Gabalfa, Riverside, Canton, Grangetown, Plasnewydd, Penylan, and Butetown.
But people in Adamsdown want action now, claiming lives are being put at risk.
Gwenda Owen, who chairs Cardiff Cycling Campaign said: “We have young children, we have older adults who may be slower crossing roads, and the difference of a few miles per hour when someone is speeding could mean the difference between life and death.”
In a statement, Cardiff Council said: “This scheme is being implemented to make the roads safer and encourage more people to leave their cars at home so they consider using public transport, walking or cycling.”
Main roads in the areas highlighted for reduced speeds will remain at 30mph, with only the residential areas reduced to 20mph zones.