Speed limit dual carriageway question?

[mickm6cmg]

I could be well off the mark as its more years than I care to remember since i had to pick up the Highway Code.


But I always thought a dual carriageway was 70 so long as it had a Barrier central reservation.


If not its a 60.


Thoughts.. am I right or just senile or could be a little from each column I guess..... :rollin
It's NSL unless otherwise indicated by speed signs.