Road closures and engineering work created severe congestion in Faringdon by restricting access to the A420.
The simultaneous closure of the A420/Coxwell Road entrance and continuing work at the Park Road entrance left London Street as the town’s only unrestricted route onto the A420.
Access along London Street was also restricted to allow Thames Water to provide emergency access.
The resulting congestion obstructed journeys for residents travelling to workplaces, schools, medical appointments and other destinations.
A Freedom of Information request submitted to Oxfordshire County Council by Faringdon Town Councillor Richard Johnson established that no combined assessment had considered the traffic effects of closing the A420/Coxwell Road entrance while Park Road works were under way.
The council said it had found no separate, recorded assessment covering all the schemes and closures included in the request.
The council’s response also showed that the effects of the closure on passengers using buses along Coxwell Road had not been assessed.
A replacement bus service ran on a reduced timetable, with its final journey finishing at 6.30pm.
Passengers relying on the S6 to reach venues including pubs and restaurants consequently had no service to return home.
Councillor Johnson said women, older residents and people with disabilities had reported difficulties travelling out in the evening because of safety concerns or physical limitations.
Concerns about the overlapping works had been raised by town councillors several weeks before the closures began.
Oxfordshire County Council explained that the Coxwell Road scheme had already experienced one delay and could not be postponed again.