Two of the offences took place within four hours, Mold magistrates’ court heard today.
Those 10 speeding infractions were detected by a fixed camera on a straight stretch of the A5104 at the village of Pontybodkin, while the 11th was in nearby Mynydd Isa.
Magistrates gave Williams 37 points on his licence, banned him from driving for six months and handed him a £600 ($1377) fine.
Williams – who is from Dyserth, North Wales, and previously had a clean driving record – apologised to the court.
He said: “I was a courier driver in a new area for me. I mistook it for a 30m/h zone.”
The change in the default speed limit in 2023 cost £34 million and affected 35% of the country’s roads.
The policy added an average of two minutes to journey times of differing lengths, according to a recent study by GoSafe, which monitors road cameras.
The decision resulted in fierce backlash towards the Welsh Labour Government, with the ruling party accused of waging a war on motorists.
Nearly 470,000 signed a petition against the law – the largest in Welsh history.
The limit has been highly controversial, with a leading Welsh businessman recently accusing the Government of making the country less attractive to tourists.
Stephen Davies, the chief executive of Welsh whisky brand Penderyn, said the restrictions made the country less appealing to visit.
He said: “The Welsh Government is not doing a very good job for tourism or for companies like ours.
“It may not be said explicitly, but we’ve got 20m/h speed limits and we’ve got tourism taxes [coming] which will apply to adults and children – I feel that a lot of that messaging basically says we don’t want you here now as a nation.”
Welsh Government figures say the move reduced collisions on affected roads by 19%, and about 100 fewer people per year are killed or badly injured in road accidents.
North Wales Police recorded a total of 97,088 speeding offences in 2024, with the 20m/h policy responsible for the majority of breaches.