FAQs

Safety is our highest priority. Hogarth roundabout is in the top 10 per cent of junctions in London in terms of road safety risk. We are proposing changes that will make the junction safer for all road users, but especially motorbikes who are particularly at risk here.

Hogarth roundabout is a busy junction, carrying large amounts of traffic. It is also an important interchange and crossing point for pedestrians and cyclists travelling to and from Chiswick, Richmond, Hammersmith, and Gunnersbury.

We have developed a scheme to improve road safety, address the causes of collisions, and make the area more accessible for pedestrians.

In the afternoon peak, traffic westbound regularly blocks back as far as the M4 junction at Chiswick, through the roundabout and back towards Hammersmith. This leads to conflict at the roundabout, particularly for traffic wishing to use the A316 which is often less congested.

By maintaining access to the flyover, traffic approaching the roundabout from the A316 Burlington Lane (both from Barnes/Richmond and Chiswick) should not experience any change to their journey. Once the new layout has had a chance to bed in, we will review and optimise the signal timings to ensure the most efficient operation of the roundabout is maintained. As bus services use this route, we will do all we can to maintain existing capacity  through signal timing  where possible.

The scheme has been designed to improve the flow of traffic for motorists using the roundabout, by providing a dedicated left turn lane for the A316, so traffic can remain in lane. We estimate a one-minute increase of journey time from Church Lane to Chiswick High Street once the Church Street roundabout access is closed as vehicles will need to use the A316 and U-turn at the right turn box just after the flyover approach.

Large numbers of HGVs use the roundabout. They currently need to take up more than one lane which can increase the risk of collisions, by providing extra capacity on the roundabout we will widen it to reduce the need to take up two lanes.

• Burlington Lane

At this initial stage our plans, we have identified that the westernmost parking bay on Burlington Lane close to the George and Devonshire Pub, could cause vehicles difficulty turning in and out of the junction if it there is a vehicle parking in it.

We are assessing this in more detail and if its removal is recommended we will refer to Hounslow Council, who manage this parking to consider its removal as part of the works.

• Mawson’s Lane

We want to create a road network that is safe for everyone. We are aware that informal parking takes place in Mawson’s Lane which can lead to unsafe manoeuvres such as vehicles mounting the pavement near to the roundabout. This is why we are proposing to remove the informal parking in Mawson’s Lane and replace it with a widened pavement and an additional lane for traffic going onto the A316.

In the morning peaks traffic regularly queues outside the brewery and concerns have been raised locally about this congestion and the effects on air pollution. By providing additional capacity here, traffic should flow better and is less likely to be stationary on the approach to the roundabout.

As well as providing an additional traffic lane, we will also provide rain gardens and planting to improve the area, turning what is currently an uninviting grey concrete environment into a more inviting, greener and more climate resilient one.

We recognise that subways, particularly if not very well maintained, can deter users, and also, feel unpleasant to those who do. This can be for a variety of reasons, but antisocial behaviour and fear of crime is often mentioned.

The subway already has CCTV coverage, we are discussing these cameras with Hounslow Council to make sure they continue to operate as intended. We will also take the opportunity to replace any older lighting units with LED fittings and undertake a deep clean of the subway to make it more inviting.

In the central courtyard area, where there is natural light, we will provide Legible London signage to improve wayfinding.

Collision data from around the world is very clear. It shows the faster a vehicle is travelling the more likely a collision will occur because the driver has less time to react, stop or avoid the collision and the more severe an injury resulting from the collision will be.

The Department for Transport suggests that streets that are self-enforcing are the most successful way to achieve compliance with lower speed limits. The look and feel of roads that are designed to be self-enforcing often mean they’re more welcoming places for people to walk and cycle too.

However, the roads we manage are London's most strategic routes, carrying 30 per cent of all London’s traffic and providing important links for freight and servicing vehicles, as well as buses. They’re also often relied upon by emergency services as the most direct roads to use when responding to an emergency. For these reasons, we’re taking a phased approach to delivering self-enforcing reduced speed limits, stepping down the limit from 40mph to 30mph so we can evaluate the effectiveness of the measures first and understand whether additional changes are needed to achieve lower speeds.

Whilst the road condition is generally good, because of the risk of collision for Powered 2 Wheeled vehicles, we will resurface the carriageway with a higher friction surface to provide additional skid resistance for these vulnerable users.

The slip road outside the brewery, after the entrance gate by Mawsons’ Lane, is a large hard surface that gives water nowhere to flow except down the drain. In heavy rain this leads to flooding on the road and overwhelms the local drainage system as water flows into and fills the drainage system closer to the river. This leads to increased water on roads close to the river as the drainage system is already full.

We are proposing building a rain garden in this space. A rain garden is a specially designed garden that collects and manages rainwater runoff from adjacent surfaces.  It would help to prevent flooding and filter pollutants before the water reaches the drainage systems.  

Rain gardens benefit the local area because:

• More green area 
• Softens the urban environment, making the street look better
• Makes the street cooler 
• Enhances wildlife habitat for bio-diversity 
• Reduces the risk of too much water resulting in floods
• Improves air quality
• Filters pollution and improves water quality

The existing roundabout environment has some green spaces but is mostly limited to grass and some smaller shrubs. Wherever possible, during detailed design and site assessment we will aim to increase the ecological diversity of the existing green spaces and break up some of the concrete paving areas with additional tree planting. We must take care however not to disturb the subway or flyover structure and trial holes will be needed to check for the presence of utility services.

If we go ahead with proposals, we will carefully consider feedback from this consultation and use it to help with the detailed design proposals. This process can take some time, to ensure we get it right. We would look to start construction from late summer 2025.

• TfL would plan construction carefully to minimise disruption to those who live, work and travel through the areas.
• We will carry out extensive communications and engagement with local residents, cyclist groups, businesses and other stakeholders to ensure they have the information they need to plan ahead and adapt their travel arrangements where necessary, reducing any impact on their journeys and operations during the construction period.
• We also routinely provide road traffic information to help people better plan their journeys and make informed choices about how, where and when they travel.

The flyover will remain open for use, as it does currently, the structure will continue to be inspected regularly. A decision will be taken on its future in due course.