Gabalfa Interchange is a major three level junction located in the northern suburbs of Cardiff. It appears that the name of the junction comes from the area it is situated within, which originally comes from Gabalva House that was situated on the site of the present day estate (source: A Vision of Britain through Time)
Original plan for the junction along with an improved A470
Bigger things were planned for the junction when originally designed. In 1966 Buchanan published a transportation report into future road proposals for the city. This would see two important roads cross at Gabalfa, an improved A470
and a new inner bypass which was opened as Eastern Avenue. A three level interchange was planned to connect these roads. The original plan was to grade separate the A470 north of Gabalfa which would have meant the loss of houses on the eastern side of the road. South of Gabalfa the flyover was to curve eastwards onto a new dual carriageway to the city centre.
In 1968 the A470 plans were shelved, possibly due to the heavy loss of property, and a slight alteration was made to the planned junction. The flyover was retained but would now tie into the existing road network. At its northern end a one way system was created and the southern end was built straighter which descends onto North Road. The roundabout was now to have an extra arm serving the A469 which originally was to be replaced by the link to the city centre. Eastern Avenue was built as planned and this took the A48 number.
Another element of the junction was the Llantrisant Radial
. This would have joined the A48 to the west. The close proximity of the junctions meant C/D lanes
were planned to reduce weaving. Gabalfa Interchange was built before the Llantrisant Radial and to help reduce later costs the west facing slips were built on a splay. This is so the retaining walls would not have to be replaced at great cost when the Llantrisant Radial was built. The Llantrisant Radial was later scrapped so the splay was not needed but the extra long slip roads can still be seen as a legacy of greater plans the never saw the light of day.