London

Construction of a new twin-bore tunnel to carry a dual two-lane road under the Thames between North Greenwich and Silvertown. The tunnel will relieve the nearby Blackwall Tunnels which run significantly above their capacity for much of the day and are prone to severe congestion and disruption. The scheme is being funded by borrowing against the receipts of a new toll which will apply to both the new Silvertown Tunnel and the existing Blackwall Tunnel, the cost of which will be matched with the tolls on the crossing at Dartford.

Upgrade work at M25 junction 10, where the motorway crosses the A3. The scheme is intended to relieve the chronic congestion suffered at this busy junction. At present all turning traffic passes through one large signalised roundabout which is operating beyond the limits of its capacity for significant parts of the day.

A large number of options were considered for the work, including radical plans to replace the junction entirely with a new free-flowing four-way interchange of one type or another. However, there are now two options remaining which have gone out to consultation.

Upgrade of several sections of the M25 to Smart Motorway between junctions 10 (the A3 at Wisley) and 16 (the M40 at Denham).

The M25 already has some Smart Motorway technology along this full length, and was in fact the first motorway in the UK to have Variable Speed Limits, which have been operational here for at least 20 years. This scheme is therefore not a standard Smart Motorway project, and instead it will introduce All Lane Running at four specific locations:

Improvements to M25 junction 28, the interchange with the A12 and A1023 west of Brentwood, to alleviate congestion that is currently a frequent problem. The existing junction is a Three Level Stacked Roundabout but extremely high volumes of turning traffic make the signalised roundabout a serious problem.

The preferred route, announced in summer 2017, is option 5F which will provide a very large looped sliproad from the anticlockwise M25 to the eastbound A12. New bridges will allow it to cross the existing sliproads to and from the roundabout.

Upgrade of an existing single-carriageway stretch of A406 North Circular Road to a dual carriageway standard. This Transport for London project is a watered down version of the improvements planned but never implemented by the Highways Agency. It involves less property demolition and is a fraction of the cost, but is unlikely to be grade-separated. Even so, any extra capacity here is welcome - it is currently a single-carriageway section of an otherwise dualled and grade-separated road in a busy urban area.