Progress report

Indicative timings of the works

This is the longest smart motorway project in England to date (51km, 32 miles). We have carefully planned our work to minimise disruption to our drivers and communities.

We started main works between junction 8/9 and 10 in July 2018 and have since progressed our traffic management west towards junction 12, and east towards junction 7. In tandem we have started enabling work on several bridges between junction 8/9 and junction 7. The more complex section of the scheme, progressing east towards junction 3, is now getting underway. Work on the carriageway between junctions 3 and 4b started in September 2019.

Bridge works

Much of the M4 was originally built as a 2-lane dual carriageway and has been upgraded several times over the years. 11 bridges over the motorway need to be replaced to make room for a new lane where there is no existing hard shoulder.

To limit local disruption, most new bridges will be built next to the existing ones, before the old one is demolished or a temporary bridge will be installed. However, where there is not enough space for this, some bridges will be demolished first, then a new bridge built in the same place.

Where the motorway passes over, for example, the River Thames at Bray, we will need to widen structures to support the new smart motorway.

Considerate construction

Wherever possible, noisier works will be undertaken during daytime hours to reduce disturbance. There will be temporary closures of the carriageway and slip roads at night on some occasions.

In these instances, the closure will be advertised, and advance warning signs and clearly signed diversions will be put in place. You can use the Roadworks section below to find information about roadworks as the scheme progresses.

The construction of the scheme is governed by the Construction, Design and Management Regulations, and we are a member of the Considerate Constructors scheme which helps ensure that we are a good and responsible neighbour.

Why we need this scheme

The M4 is the main strategic route between London, the West of England and Wales. It connects people, communities and businesses, carrying on average 130,000 vehicles per day and is prone to congestion.

Highways England will be improving the M4 between junction 3 at Hayes and junction 12 at Theale by upgrading it to a smart motorway which will provide much needed capacity and support the economy and facilitate economic growth within the region. This means there will be:

• an additional lane for traffic increasing capacity to reduce congestion
• more technology on the road to smooth flows and manage incidents
• more reliable journeys

The scheme in detail

This scheme will use the latest technology to improve journeys by monitoring traffic flow and setting speed limits accordingly. This helps to keep traffic moving smoothly, instead of continually stopping and starting.

Information about road conditions and speed limits will be displayed to drivers on electronic road signs.

Key changes to the motorway

All Lane Running: between junctions 3 and 12 the hard shoulder will be converted to a traffic lane, so that there are four lanes available for use by road users. Between junctions 4 and 4b, there will be five lanes. There will also be five lanes on the eastbound approach to Junction 4b.

Where a hard shoulder does not currently exist, the motorway will be adapted to create a minimum of four lanes, including the replacement of bridges. The barrier in the central reservation will be replaced by a new concrete barrier.

Through junction running: This enables a consistent number of lanes to pass through the junction, reducing the need to change lane for vehicles staying on the motorway. Through-junction running will be in place at several junctions on the smart motorway where it is assessed to be appropriate.

Bridge works

To accommodate the new smart motorway 11 bridges carrying local traffic over the motorway will need demolition and replacement.

Where the motorway passes over, for example, the River Thames at Bray, we will need to widen bridges to support the new smart motorway.

Several subways, including at Sipson, and several culverts that run under the motorway will also need work in order to accommodate the upgrade.

Emergency areas (EAs): there will be new high visibility Emergency Areas between junctions 3 and 12. Places of relative safety will be every 1.12 miles on average and no more than 1.6 miles apart. If you are driving at 60mph you will pass one approximately once every 90 seconds.

Aims

• reduce congestion
• smooth the flow of traffic to improve journey times
• make journeys more reliable
• support the economy and facilitate economic growth within the region, by providing much needed capacity on the motorway
• continue to deliver a high level of safety performance on the network using smart motorway techniques and minimise environmental impacts of the scheme

Development Consent Order (DCO)

The DCO process was established by the Planning Act 2008 and is used for certain large and complex schemes (including highway improvements) that have been designated as a Nationally Significant Infrastructure Project (NSIP) by the Government.

The benefits of the DCO process include extensive pre-application consultation, detailed analysis, including a full Environmental Impact Assessment, and examination by an independent inspector before the final decision is made.

Development Consent Order – requirements register

We made a commitment to publish and update a register listing the requirements to be completed as part of the Development Consent Order (specified under the Register of Requirements in Schedule 2). This sets out:

• each requirement
• whether the requirement needs approval by the Secretary of State (or other duty holder)
• whether any approval has been applied for or given

All of the DCO requirements needed to start work were discharged in summer 2018.

Considerate construction

Wherever possible, noisier works will be undertaken during daytime hours to reduce disturbance.

There will be temporary closures of the carriageway and slip roads at night on some occasions. In these instances, the closure will be advertised, and advance warning signs and clearly signed diversions will be put in place. You can use the Roadworks section below to find information about roadworks as the scheme progresses.

The construction of the scheme is governed by the Construction, Design and Management Regulations, and we're a member of the Considerate Constructors scheme which will help ensure that we're a good and responsible neighbour.

Environmental impact

As part of the DCO planning process, a full Environmental Impact Assessment was carried out and has been used to inform the design of the project. This included assessments and design of mitigation where needed for:

• air quality
• cultural heritage
• landscape
• ecology and nature conservation
• geology and soils
• materials
• noise and vibration
• effects on all travellers
• community and private assets
• road drainage and the water environment

During the examination of the application, further environmental protections were requested and planning requirements attached to the consent.