The cost of using the M6 Toll road is to rise next month.
From 0600 BST on 14 June, motorbikes and cars will pay an extra 50p and vans and heavy good vehicles (HGVs) will pay an extra £1.
Existing electronic tag customers - for pre-paid journeys - will continue to get a discount, say operators Midland Expressway Ltd (MEL).
But the Freight Transport Association said some firms may be forced to discontinue using the 27-mile route.
More vehicles
The rise means HGVs will now pay £7 to use the privately-funded road and cars and small vans must pay £3.50.
MEL said it was the first real increase in prices and still gave good value for money.
In August last year, the price rose by £1 after the 10 millionth customer used the road, something which its operators said would happen when it was first opened in December 2003.
A spokesperson for the National Alliance Against Tolls said: "The government wants more tolls, but roads users do not want any.
"We urge roads users to send a message to the government by avoiding tolled roads as far as possible."
The UK's only toll motorway links junction four of the M6 at Coleshill, Warwickshire, with junction 11 near Cannock, Staffordshire.
Figures showed that the number of vehicles using the route in January this year rose by 25% on the same month in 2004, taking the average daily traffic to 43,344, compared to 32,763.