Council bosses also propose a Cardiff Circle Line that links large residential areas using an orbital light rail or tram.

The two measures form part of a £1Bn transport plan from Cardiff Council, outlined at a conference on Thursday by leader Huw Thomas to cut congestion and improve air quality in the capital.

“Cardiff's transport network needs to change,” he said. “It was originally designed for a city with a population of 200,000, but today our population is closer to 400,000 and there are another 80,000 commuters travelling into the city by car every day.”

He added that the transport vision is for a “greener, more sustainable city” that could “transform the way people move around by 2030”.

He said the council will work alongside partners including the Welsh Government and have “a serious public conversation about how this vision can be funded”.

Further transport measures announced include plans for a new bus rapid transit network, a park and ride site at junction 32 of the M4 to connect to the Circle Line, new cycleways and walking routes, integrated ticketing and making Cardiff a 20mph city.

Cardiff Council cabinet member for strategic planning and transport Caro Wild added: “This vision represents some early ideas which have followed on from last year's Transport & Clean Air Green Paper. It sets out our direction of travel. We will be bringing forward a White Paper in the autumn with more plans for the city, but we were keen for the conversation to begin now.”

(Image: Cardiff Council)