Yeah, that is something to avoid. Say things like:
"I fully realise that I was speeding, and I'm not contesting that, I'm pleading extenuating circumstances, in that...."
and if the road was bad as you said:
"Your worship (GET HIS TITLE RIGHT!!! Listed to what the lawyers/prosecutors before you address him/her as!!!!), I'm not sure if you are familiar with that road, but I am, having travelled along there everyday/regularly for the past x years. It isn't in good condition, and under NO OTHER circumstances would I EVER IMAGINE to exceed the speed limit there."
Anyway... You're probably asleep by now. Good luck.