 Car drivers must pay �2 to use the new road |
The M6 Toll motorway is fully connected to the rest of the motorway network.
The road partly opened on Tuesday and the process to open it to northbound traffic from the M42 and M6 started on Friday night.
The southbound access opened fully on Saturday evening.
The road's operator, Midland Expressway Limited, says motorists will now have a chance to avoid congestion and save time on their journeys.
Managing director, Tom Fanning, said: "We've been really encouraged by the tens of thousands of motorists who have tried out the road over the past few days.
"We're sure many more people will choose to avoid the notorious congestion black spots around Birmingham."
Motorists pay will have to pay �2 to drive along the 27-mile route, formerly known as the Birmingham Northern Relief Road.
This will rise to �3 after 10 million vehicles have used the road.