As of the start of this week, 33,000 people had so far been issued permits.
These allow motorists to go through a congestion charging point without paying when the scheme begins next week.
Councillor Andrew Gant, the council’s transport chief, said: “As a soft launch, the council has decided to operate a ‘grace period’ whereby a letter will be sent to remind car drivers that, on their first time driving through a temporary congestion charge point without paying or using a permit, the charge is now in operation and they can apply for permits.”
Earlier on Tuesday, it was revealed that the authority had spent £73,000 on the online permit system that is being used for the charge.
Conservative councillor Liam Walker, leader of the Oxfordshire Alliance opposition group, said the cost was “staggering”.
He said so many residents found the system “confusing and unreliable”.
