Multiple choice general knowledge The national speed limit on dual-carriageways is:- 40 mph 50 mph 60 mph 70 mph Reveal answer Fill a bubble to check yourself D Correct answer Explanation The national speed limit for cars and motorcycles on dual carriageways in the UK is 70 mph. Single carriageways have a 60 mph limit, but dual carriageways with a central reservation allow the higher 70 mph speed limit unless otherwise signed.