Cardiff Traffic Delays Grow Amid Castle Street and Callaghan Square 2026

Key Points

• Cardiff city center is witnessing heavy traffic congestion due to ongoing roadworks in Castle Street and various other main roads.
• Roadwork at Castle Street started on 23 February 2026 and it was expected to be completed in around 52 weeks’ time.
• Temporary traffic lights will be in place at the junction of Castle Street and Westgate Street between Monday, 21 September and Friday, 25 September.
• Cardiff Bus has warned of delay on all its routes because most of them go through this junction.
• One commuter says that it takes around 25 minutes to travel from bottom of Cathedral Road to Westgate Street during peak morning hours.
• Traffic congestion is also being caused in Duke Street and North Road owing to traffic back up from Castle Street.
• Traffic congestion is also being caused by separate work taking place in Callaghan Square as part of the Cardiff Crossrail program. This work has also brought temporary traffic arrangements in Bute Street starting from 20 September.
• According to Cardiff City Council, the work at Castle Street involves upgraded pedestrian crossings, removal of a traffic island and resurfacing of the carriageway.

Cardiff (Wales Times) September 25, 2026 – uk/local/cardiff/">Cardiff city centre has been hit by heavy congestion as major roadworks continue across Castle Street, Duke Street, North Road and Callaghan Square, causing disruption for motorists and bus passengers.

As reported by Herald Wales, Cardiff city centre has “descended into traffic chaos as works are carried out on a number of key roads”. The report describes queues building along Castle Street and extending through Duke Street and onto North Road, with temporary traffic lights adding to delays at the Castle Street and Westgate Street junction.

The Castle Street scheme began in February, when work started to make a temporary road layout and cycleway permanent. According to WalesOnline, the road remains open to traffic, but congestion has regularly built up along its length, particularly during peak periods.

Cardiff Council said in a public update that the works include upgraded pedestrian crossings, the removal of a traffic island and carriageway resurfacing. The council advised road users to use alternative routes where possible and allow extra time for journeys.

How long will the Castle Street roadworks last?

Work began on site on 23 February and was expected to take approximately 52 weeks to complete, according to WalesOnline. That timetable indicates the works are expected to continue into early 2027.

The council’s update did not provide a revised completion date. However, it confirmed that work was continuing on Castle Street, including at the Westgate Street junction.

Nation.Cymru reported that three-way traffic lights would operate around the clock at the Castle Street and Westgate Street junction from Monday, 21 September until Friday, 25 September as part of the ongoing works.

What have bus passengers been told?

Cardiff Bus warned passengers to expect significant delays while the temporary signals were in operation. As reported by WalesOnline, the transport company said it would “do everything” to keep services running and minimise disruption.

The company said most Cardiff Bus routes pass through the Castle Street and Westgate Street junction, meaning substantial delays were anticipated. It also warned that disruption could spread across the wider bus network.

Nation.Cymru similarly reported that bus passengers were being warned to expect significant delays during the week, with the three-way signals operating continuously at the key junction.

What have commuters experienced?

One commuter described the impact of the congestion on their morning journey. As quoted by WalesOnline, the commuter said: “I got the first bus of the day from north Cardiff and usually make it to the city centre by 7.45am but we hit the traffic at the bottom of Cathedral Road and it took about 25 minutes to get from there to Westgate Street. It was chaos.”

The account reflects the scale of delays reported around the western approaches to the city centre, where traffic from Cathedral Road feeds towards Castle Street and Westgate Street.

Which other Cardiff roads are affected?

Congestion has not been limited to Castle Street. WalesOnline reported that traffic has been backing up through Duke Street and onto North Road, while work to redevelop Kingsway is also causing disruption in the city centre.

Separate works at Callaghan Square, which form part of plans to develop the Cardiff Crossrail network, have added to pressure on routes near the city centre and Cardiff Bay. WalesOnline reported that congestion has been heavy in other parts of Cardiff during peak times as those works continue.

What traffic changes apply at Callaghan Square?

WalesOnline reported that temporary traffic arrangements were introduced on Bute Street from 20 September. Under the arrangements, Bute Street from Butetown at its junction with Callaghan Square is open for northbound traffic.

Traffic travelling north towards Herbert Street or Tyndall Street is required to turn left. This allows vehicles to travel westbound or use Callaghan Square to travel northbound or eastbound via the roundabout.

There is no southbound access onto Bute Street from the Callaghan Square junction. WalesOnline reported that streets located south of Callaghan Square off Bute Street are only accessible from the south, with diversion routes via Lloyd George Avenue and Dumballs Road.

What other roadworks are affecting Cardiff?

Further afield, WalesOnline reported that significant flood-prevention works began on Lamby Way in Rumney on 20 September. Temporary traffic signals were placed between the Southern Way and Lamby Way roundabouts, with both directions of traffic expected to remain open.

According to the report, the temporary signals are expected to remain in place until late February next year. A lane closure at Lamby Way roundabout was installed on 20 September, followed by major piling works towards Lamby Way bridge between 5 October and 11 December.

The works schedule also includes night closures from 14 to 23 December to remove piling equipment and install pile caps, a reduced-traffic Christmas shutdown from Christmas Eve to 3 January, and handrail installation and equipment removal between 8 and 26 February.

Background of the development

The Castle Street project is part of a longer-term effort to make a temporary road layout and cycleway permanent. Work began on 23 February 2026, with an initial expected duration of approximately 52 weeks.

Cardiff Council has said the works involve upgraded pedestrian crossings, removal of a traffic island and carriageway resurfacing. The council has urged drivers to plan ahead, use alternative routes where possible and allow additional time for travel through the city centre.

The congestion comes as Cardiff also manages separate infrastructure schemes at Callaghan Square, Kingsway and Lamby Way. The Callaghan Square works are connected to plans for the Cardiff Crossrail network, while the Lamby Way scheme forms part of flood-prevention measures.

Prediction: How will this affect commuters and businesses?

For commuters, the immediate effect is likely to be longer and less predictable journeys through the city centre, particularly during morning and evening peaks. Bus passengers may face the greatest disruption because most Cardiff Bus routes pass through the Castle Street and Westgate Street junction.

Drivers travelling from western Cardiff, including areas served by Cathedral Road, may continue to experience delays as traffic queues towards Westgate Street. Those using routes around Callaghan Square, Bute Street, Lloyd George Avenue and Dumballs Road should check diversion arrangements before travelling.

For city-centre businesses, continued congestion could affect staff arrival times, deliveries and customer visits. However, the impact will depend on how effectively travellers adapt by allowing extra time, changing departure times or using alternative routes while the works continue.