The 23km of roadbuilding work will be let in separate two-stage design and build contracts to connect to what will be the longest road tunnel in the UK.
The £1.3bn Roads North of the Thames contract will run from Junction 29 of the M25 to 1km before the northern tunnel entrance.
While the £600m Kent Roads contract will run from the A2 to 1km out from the southern portal.
The whole scheme including the £2bn tunnel and approaches contract, which is being let separately, ranks as the largest single road investment project since the M25 was completed more than 30 years ago.
Matt Palmer, Lower Thames Crossing Executive Director, said: “These contracts show our commitment to this project, which will support 22,000 jobs during its construction.”
“Our challenge is to build the new crossing in a way that not only supports the next generation of low carbon vehicles, but minimises our footprint, and allows us to enhance the natural environment and leave a positive legacy for our neighbours and users.”
The successful bidders and their supply chain will be expected to help Highways England achieve its ambition of making the Lower Thames Crossing the most environmentally sustainable road project ever delivered in the UK.
This will include planting over 260 hectares of new woodland, converting 400 hectares of arable land into semi-natural habitats, and creating new ponds, waterways, ditches and hedgerows.
Seven new green bridges will be built to connect habits and species either side of the new road.
Kent Roads contract
- 6km of new road, including a multi-level junction to connect the A2 to the Lower Thames Crossing
- Environmental mitigation is a the heart of our scheme, most visibly with two “Green Bridges” at Thong Lane & Brewers Road, these bridges are combine green spaces with walking, cycling and vehicle access and provide better connectivity for the landscape, ecology and habitats. Brewers Road will also cater for horse riders.
- The road has been design to minimise impact, and has extensive landscaping new and upgraded structures, embankments, cuttings and retaining walls.
- The diversion of utilities including strategic gas mains, electricity cables, water, and telecoms
- Ecological works for species protection and habitat enhancement along the route
Roads North of the Thames contract
- 16km of new road with over 30 proposed new and/or upgraded structures, embankments, cuttings and retaining walls, under bridges to take the route through the A13 and to join the M25 at Junction 29
- Environmental mitigation is at the heart of the scheme, the roads north of the Thames contract is extensively screened by bunding and landscaped along its length, with 5 “green bridges” these bridges are combine green spaces with walking, cycling and vehicle access and provide better connectivity for the landscape, ecology and habitats.
- Two viaducts at Tilbury over Tilbury Loop Railway and at across Orsett Fenn over the Mardyke flood plain. Both have been design to enhance connectivity under the crossing, supporting local community access.
- The diversion of utilities including gas mains and electric cables and towers.
- Ecological works for species protection and habitat enhancement along the route.