A car overturned near a traffic calming measure in Drayton Park on Monday afternoon.
The emergency services were called to the scene just before 4pm to find a white Toyota iQ turned on its side after attempting to pass through the restriction.
According to witnesses, the driver and passenger escaped the car unharmed and the road was reopened at around 5pm.
This is the second car to turn over at the traffic restrictions since they were put in place in July 2012.
The £80,000 traffic island has been criticised by local residents and businesses and last September Islington Council was forced to spend a further £30,000 to modify the restrictions in response to complaints.
Chair of community group Islington Living Streets, Caroline Russell, said: “If cars are turning themselves over at this point it suggests that it’s not designed in a way that drivers understand how to use it.
“They’ve put in something which encourages people to drive as if it’s a main road. It’s not a main road, it’s increasingly residential.”
An Islington Council spokesman said: “This lorry ban width restriction was put in at local residents’ request for safer streets. We are continuing to monitor the restriction, and also planning further measures to stop traffic speeding in this 20mph road.”
