The go-ahead has been given for an eastern bypass for Lincoln.
County councillors granted planning permission for the multi-million pound road scheme after discussions spanning more than 10 years.
The new road will connect the A158 Wragby roundabout with the A15 near Bracebridge Heath.
The council said the approval was the start of a long process. The government must agree funding, and objections to the route have to be dealt with first.
Lincolnshire County Council's Head of Planning Alan Freeman said the plans will be included in a transport study and the council will then apply for central government funding.
He added that compulsory purchase orders of land will then have to be issued and any major objections will have to be dealt with in a public inquiry.
Work is expected to start in 2008 at the earliest.