Years ago when I did mine we were told that something like 97% of road fatalities occur in 20/30 zones. For the most part dual carriageways are perfectly safe to do 80+ because they're pretty straight with great visibility and little in the way of hazards.I know I called myself captain slow Afew posts back but on my commute to Padstow I'm doing maybe 45 to 50 on the 50, 60 on the duel carriageway, had a speed awareness course years back and it sunk in
What I walked away with was, "Stick to the 20/30 limits and don't sweat the others.
![Stick Out Tongue :p :p](/styles/default/xenforo/vbSmilies/Normal/tongue.gif)
And people who drive 40mph everywhere just wind up all the other road users, which in itself is unsafe.