Traffic on the M6 Toll has been dropping in the months leading up to its second anniversary of opening.
The toll motorway opened in 2003
The daily number of vehicles in November was 44,583, down 5% compared with 47,057 in 2004, a sixth monthly decrease on figures from last year.
Operators said in 2004 road works on the M6 saw more people use the toll and a drop in the months towards the end of the year was not unusual or unexpected.
A group against tolls said if it was removed traffic flow would increase.
The M6 Toll road opened in 2003 as the UK's first pay-as-you-go motorway.
'Less fuel and time'
Prices were raised in June to £3.50 for cars and £7 for HGVs. The government is looking at plans to extend it towards Manchester.
Midlands Expressway Ltd chief executive Tom Fanning said: "As anticipated, seasonal factors have had an impact, with weekend journeys most affected.
"But this is a reflection of traffic patterns generally at this late time in the year as drivers face deteriorating weather and shorter daylight hours.
"Whilst the use of the toll road still remains a personal choice for motorists, we've made it even easier for our customers to choose the M6 Toll and enjoy the benefits of the road by introducing a discount scheme."
A spokesman for the National Alliance Against Tolls said: "What is the point of building roads and then having them empty because of tolls?
"This is crazy, particularly when there has been an accident on the M6, or there are road works.
"If the tolls were removed from the M6 Toll, there would be a better overall flow of traffic and less fuel and time would be wasted."
The UK's only toll motorway links junction four of the M6 at Coleshill, Warwickshire, with junction 11 near Cannock, Staffordshire.