The chosen route for the Lower Thames Crossing will link the A2 and M25 and generate more than £8bn for the economy, according to transport secretary Chris Grayling.
The new road, which will cost an estimated £4.4bn, will run from the M25 near North Ockendon, cross under the Thames east of Tilbury, and link to the A2 near Shorne.
Grayling said the route chosen for the river crossing was voted for by the majority of 47,000 participants in a public consultation.
The crossing is expected to carry 4.5 million HGVs in it first year, reducing the burden on the congestion-plagued Dartford Crossing.
A further £10m will be spent on improving traffic flow at the Dartford bridge and tunnel.
A DfT spokesman said while the department hopes the road will be open by 2025, it was too soon to say when building work would begin.
He told Freight in the City: “We’re not putting a timescale on it at present because it’s still too early. We’re announcing the location, but the crossing needs more design work and thought on how it will deal with traffic and physically link to the A2.
“Once more of that’s decided and DfT is ready to make its plans public, there will be another public consultation.”
The transport secretary has also earmarked £66m to widen the A13 Stanford-le-Hope bypass from two to three lanes.
This, he said, would create 4,000 new jobs in the area and improve access to the Tilbury and London Gateway ports.
The RHA welcomed the announcement about the new route, but voiced concerns that with rapidly increasing traffic levels, it could be obsolete before it is completed.
Chief executive Richard Burnett said: “The new crossing will have a tremendously positive economic benefit.
“The project will provide thousands of jobs and will give a boost to business across the South East.
“Our main concern is that the anticipated completion date will be 10 years from now. If traffic levels continue to increase at their current levels, the new crossing may be obsolete before it even opens.”