Belfast has 2 of the the top 3 congested roads outside London.
Belfast unfortunately holds the title of the most congested road outside London with the A1 Southbound between College Gardens Belfast to Wallace Park Lisburn via the Lisburn Road was busiest in the afternoon where drivers lost 49 hours in congested traffic in 2016 according to traffic analysts Inrix study. The A24 Northbound between Ormeau Road to Ann Street, Belfast was third on the list with drivers losing a total of 45 hours was busiest in the morning. Both these roads appeared in the Top 10 of most congested roads in the UK with them appearing 6th and 9th respectively.
Traffic analysts Inrix also reported on traffic jams within the UK in 2016 as detailed in the article.