Forum Topic

Diversion Route for South Parade Closure?

With no word from Ealing Council on this it looks like they are determined to proceed with the closure of South Parade despite the fact that the A4 westbound lane closures are extended through the half term.Do we know yet what the official diversion route will be - the choices seem to be left on TGT along CHR to rejoin Acton Lane or right up The Avenue, along Southfield Road and then left onto Acton Lane? Neither seem particularly palatable but the latter is probably the worst because it will inevitably result in people trying to bypass the queues by cutting through residential back streets in Acton Green and Bedford Park.Is there a protocol among councils in which it is seen as bad form to divert traffic to another borough, therefore Ealing will feel obliged to take the worst option for their residents?

Anita Blake ● 1433d47 Comments

One thing they made do is terminate the 94 earlier. I don't think The Avenue and Southfield Road could function with two double decker bus routes operating on them. Quite where they would put the terminus is another question.

Mark Evans ● 1433d

The only through traffic that would take the route you suggest would be heading between Bath Road and Bollo Lane; from Bath Road any traffic heading along the High Road would just cut down at TGT earlier while any heading northward would head up the Avenue. Similarly eastbound traffic from Bollo Lane will easily divert up Acton Lane or down to the High Road.There's very little traffic that heads between Bollo Lane and Bath Road. Only 10% of the westbound traffic on Acton Lane turns into Bollo Lane at the Chiswick Park Station roundabout, less than 500 cars a day, and some of that will becoming down Acton Lane rather than South Parade, and less than 400 a day turns from Bollo Lane to Acton Lane.  Hence very little through traffic will be affected by a closure of South Parade.That leaves just local traffic on the few streets that find themselves on the wrong side of the closure for their usual route along South Parade. Some of those streets will see a few more of their neighbours cars as they take an alternative route round, and some, like South Parade, will see rather less.

Tom Pike ● 1432d

Tom says:' from Bath Road any traffic heading along the High Road would just cut down at TGT earlier'That would be the TGT that at busy times has traffic queuing back from the CHR junction as as far as the tube station, an even more regular occurrence now with the A4 roadworks. The average green phase for TGT traffic is around 9 seconds.Traffic heading westbound on CHR is often static again due to the roadworks, making it even harder for TGT traffic to join.I often wonder if some people actually travel around W4 and see the reality on the ground. Or realise that far more traffic is currently using South Parade due to the A4 roadworks? Quite staggering.

Bill George ● 1432d

Bill totally agree the traffic on TGT and South Parade is staggering and yet Ealing Council seem immune to hearing and more importantly listening to residents who they take money from and are supposed to protect. The traffic management in the whole of chiswick in recent times is extremely poor, councils need to get together to find resolutions for chiswick residents. I took a taxi to hospital yesterday and even the taxi drivers are avoiding Chiswick wherever possible.

Jayne Thorburn ● 1432d

The need to open up Fishers Lane. Obviously.

Mark Edwards ● 1432d

Of course you just add to the queue down TGT to CHR rather than the one on Acton Lane. If either junction is the bottleneck, traffic can come down Goldhawk Road.Closing South Parade make no difference to the final destination of traffic diverted from the A4. The overall flow is not changed by allowing the same traffic to take more routes to end up in the same place - it's just distributed over different roads.

Tom Pike ● 1432d

Tom it is called congestion, TGT and South Parade are already badly congested during commuter times and sometimes there are other pinch points throughout the day your suggestion is unacceptable

Jayne Thorburn ● 1432d

South Parade won’t be congested if it’s closed! The queue instead will be on Bath Road. Is that swap unacceptable?

Tom Pike ● 1432d

Tom, my question was about which the official diversion route would be rather than which was the best for drivers to take. You also seem to be far too sanguine about the impact on local streets. I walk up by Acton Lane towards Chiswick Park station regularly and can see that a substantial proportion of traffic coming south turns into Sainsbury's. This makes sense because at least half of the parking for the centre of Chiswick must be there.When South Parade is closed some of this traffic may choose to turn down TGT and CHR but these are already congested but if the diversions is up The Avenue then that is the way many will go. These roads are not equipped to deal with a significant increase in traffic. Mark makes a good point that an early termination of the bus might help but the offset is that the lack of a local bus service might force more people into their cars.We'll see next week whether or not your rosy assessment of the situation is correct.

Anita Blake ● 1432d

The excess traffic on South Parade at the moment is through traffic diverted because of the A4 restrictions. It's not going to take a long local diversion, and indeed the diversion signs should be down TGT to the High Road, which is the best route in any case.Closing South Parade will reduce through traffic on Acton Lane to CHR - South Parade is the main feeder. Residents to the west of South Parade, as well as those on South Parade itself will benefit from lower traffic, at the cost of those on Bath Road. Overall traffic will fall as drivers seek better alternatives.

Tom Pike ● 1432d

Just got back having walked the CHR is heavily congested, the cycle lane is out even in sections where there is zero work does anyone have a brain cell…..clearly not. They can not close south parade in conjunction with the A4, people are already avoiding chiswick which suggests that the traffic is for essential journeys of some description. No local person would use their car to shop locally, traffic and parking a nightmare.

Jayne Thorburn ● 1432d

Tom, can I suggest you reread my original post because you seem to have missed all of the points I was trying to make.I entirely agree that directing traffic down TGT and the High Road would be best but was concerned that local government protocols might not allow Ealing to do that - they would be adding to the existing congestion in an neighbouring borough.I respectfully suggest that a significant proportion of drivers will follow the signed diversion even if it is not the best way for them to reach their destination.Once again your panglossian insistence that traffic will decline overall is quite astonishing but, as I said previously we won't have long to wait to see if your determined optimism is justified. The 'better alternatives' drivers seek may well be Abinger Road, Woodstock Road, Speldhurst Road, Somerset Road and Fletcher Road.

Anita Blake ● 1432d

I may be wrong but wasn't Tom one of those in favour of making Turnham Green  Terrace an LTN?

Bruce Hammal ● 1432d

On that point, while the roadworks are in Ealing, any meaningful diversion signs, at the approach to the Bath Road/TGT roundabout and at the CHR/Acton Lane junction, would be in Hounslow. I do agree, signage is important. Whatever might be the rational route, satnav led many drivers on a wild-goose chase down to Chiswick Mall before signage was put up.  "Once again your panglossian insistence that traffic will decline overall is quite astonishing."It's not my insistence, it's an observation. When Hammersmith Bridge was closed, traffic simply did not go up on any of the neighbouring bridges.  The High Road's traffic has fallen by over 50% over the last couple of decades, and that's including the 10% increase we've seen during the A4 restrictions. You will have to get used to being astonished!

Tom Pike ● 1432d

Tom your posts are becoming nonsensical and beyond parody.Leave your ivory tower and walk around W4 and see the queues, then stop making silly posts that traffic go down TGT, that is already solid with queueing traffic. Similarly the issue of traffic evaporation and bridges has been done to death. London has few bridges and most key approach roads were already at capacity. It was therefore pretty much impossible for traffic to go up on the neighbouring bridges, but we did see a lot more congestion on approach roads. People also adjust plans/ delivery routes/ shopping habits to avoid crossing bridges. THere was no actual fall in traffic around the bridge, neither Richmond nor hammersmith. WHich completely disputes the myth that traffic evaporated.Your traffic counts will show that traffic fell through W4 during the A4 roadworks and no doubt in future you will claim traffic evaporated. Conveniently for you there are no cameras to capture the gridlock and you dont/ cannot measure gridlock.

Bill George ● 1432d

Tom says:‘There's very little traffic that heads between Bollo Lane and Bath Road. Only 10% of the westbound traffic on Acton Lane turns into Bollo Lane at the Chiswick Park Station roundabout, less than 500 cars a day, and some of that will becoming down Acton Lane rather than South Parade, and less than 400 a day turns from Bollo Lane to Acton Lane.  Hence very little through traffic will be affected by a closure of South Parade.’Very precise numbers there, and suspiciously low. Is there a reliable source for these figures or are they mined from the Rachel Aldred big book of facts?

Simon Hayes ● 1432d

You are simply making a series of conjectures to try to retrieve your position when it is a fact that traffic has not increased on the other bridges after Hammersmith closed. And the traffic on the other bridges in 2019, after Hammersmith closed, was down 13% on 2015, so your assertion that those bridges couldn't cope with any increase doesn't bear much scrutiny.All the local trips that used that Bridge have effectively found other ways to travel, to the benefit of those living on Barnes and in Hammersmith south of the A4: most of the trips across Hammersmith Bridge were not by car in the first place. However, half of the car traffic that wasn't local is now keeping to the A4/M4 and M25, as it should, rather than driving through residential streets to the A3. As far as Chiswick is concerned, again your conjectures are off. Given the A4 takes 35,000 each way compared to the High Road's 6,000, even if a good fraction of the A4 were to evaporate, it should not have been surprising that the High Road has seen a step up in traffic. In fact traffic counts on the High Road saw a 40% increase westbound at peak times just when the restrictions on the A4 were introduced. But that's only around 1000 additional vehicles, concentrated in just four hours, so the increase in traffic on the High Road could well be associated with an overall fall in A4 traffic. Given the evidence from elsewhere, it is highly likely that a proportion of those using the A4 are not making those trips any more.

Tom Pike ● 1432d

Have a look at the data Ealing supplied to support making the restriction on Fishers Lane permanent: 13. Chiswick Pk Stn only JTC 01 May 2021That gives 344 vehicles from South Parade/Acton Lane heading to Bollo Lane compared to 5496 to the High Road, or 6%. In the reverse direction it's 504 vehicles or 10%.The vast majority of traffic to or from the west end of South Parade is heading to the High Road.

Tom Pike ● 1432d

Tom, even you have to recognise that simply counting the number of vehicles crossing bridges before and after the Hammersmith Bridge closure can not be used as a proof of traffic evaporation.

Jeremy Parkinson ● 1432d

Road bridges clearly define routes for certain trips that have end points on different sides of the river. If those trips are no longer driven using any bridge, the road traffic associated with those trips has evaporated.Maybe you could explain how those trips continue to be made by car without crossing any bridge.

Tom Pike ● 1432d

Isn't there a conundrum with traffic measuring that a grid-locked road would show the same number of cars passing a point as a deserted one? So could Tom's measurements suggesting 'less traffic' in fact be the slow moving queues that many local residents observe?

Peter Evans ● 1432d

You are of course correct that zero flow could be down to an empty or gridlocked road. But gridlock is an overused term that should only really describe a specific state of traffic where obstruction of junctions prevents any flow.  What we almost always see is the more prosaic congestion, where traffic still flows but at lower than its maximum value. That still means people can complete their trips and the traffic counts will not be impacted, just spread over a longer period.

Tom Pike ● 1432d

"Road bridges clearly define routes for certain trips that have end points on different sides of the river. If those trips are no longer driven using any bridge, the road traffic associated with those trips has evaporated."Maybe you could explain how those trips continue to be made by car without crossing any bridge."Just off the top of my head - all takeaway orders will be now delivered from the same side of the bridge, north and south- other kinds of deliveries will now be staged from depots at the right side of the bridge- shopping and leisure excursions will now be rerouted to avoid crossing the river- journeys from outside London will enter the capital at a different point. For instance someone heading to Hammersmith from the South West who may have come via the A316 will now go round the M25 to the M4/A4.There are scores of other ways in which travel patterns will change making the simplistic counting of vehicle movements on bridges valueless as a measure.You will always be able to 'prove' evaporation by taking a limited snapshot of data but the reality is that it is a very complex matter and it is all but impossible to say definitively that fewer journeys have resulted from a change. My fear would be that even if there has been a slight fall the extended journey times for the vehicles that remain will result in more congestion and pollution in a wider area.As far as I am aware Ealing Council have not relented on their insistence that Fishers Lane remains closed even when South Parade is shut. They may have bought into your theories but I think it is more likely the revenue that will result from frustrated or confused drivers using the underpass is too great to pass up. They believe a few days of chaos in Bedford Park and South Parade will be worth it for the extra cash.

Jeremy Parkinson ● 1432d

Before you correct me on a point of detail - obviously South Parade is less likely to see traffic chaos during this period. I meant to say Bedford Park and Acton Green.

Jeremy Parkinson ● 1432d

Gridlock may be overused but severe congestion is common and gridlock in fact over last couple of years has been the reality on many, many occasions in W4.Tom you also choose to ignore is that many key junctions and routes are in normal times at or close to capacity. This is true of key roundabouts like Hogarth and Chiswick, as well as several other junctions across W4. Once one of these key junctions seizes up then the congestion rapidly spreads across a wider area. If you actually walked and/ or cycled around W4, which you never seem to do, you could observe the current gridlock on certain routes and then understand how pointless your suggestion that traffic divert down TGT when SOuth Parade is closed. Traffic counts are indeed impacted by such traffic conditions.Let me pose you a simple question, what would a traffic counter on the A4 westbound through W4 currently show vs one pre the roadworks. More or less traffic. Please do answer... As for how people adjust to a closed bridge, it is staggeringly obvious and has been explained to you multiple times. The fact is that neither the boroughs of Richmond or H&F showed any reduction in traffic volumes when the bridge was closed so it was clear that most of the traffic rerouted rather than tried to cross another bridge. It would be quite staggeringly illogical to assume anythign different.

Bill George ● 1432d

Hammersmith Bridge.When/if it is repaired we need to think 20 to 100 years into the future. It would be a mistake not to bring it to a standard where it could take motor vehicles as we can't know how important this will be to future generations.Temporary fixes or ones designed to take only people is  short sighted so people advocating this need to rethink.The costs of repairing to  full functionality compared to a half baked job may be more in the short term but long to medium term it will doubtless be money well spent.

Adrian Irving ● 1432d

Tom says:‘Have a look at the data Ealing supplied to support making the restriction on Fishers Lane permanent: 13. Chiswick Pk Stn only JTC 01 May 2021That gives 344 vehicles from South Parade/Acton Lane heading to Bollo Lane compared to 5496 to the High Road, or 6%. In the reverse direction it's 504 vehicles or 10%.The vast majority of traffic to or from the west end of South Parade is heading to the High Road.’So traffic counts taken on a Saturday. A bank holiday weekend. And on behalf of a council proven to manipulate figures to try to ‘prove’ something that doesn’t exist. And you think stats can’t lie? The people who used certainly can.

Simon Hayes ● 1432d

Undoubtedly some of the trips across the bridge, where a viable option exists on the same side of the river, will be substituted, and not all driven. The Richmond survey of residents showed a transfer to rail and other bus routes. It’s also notable that businesses in Barnes have seen increased takings after the closure. These are both commendable outcomes as a direct result of the closure. There will also have been some substitution of trips on the neighbouring bridges, with the highest value trips that used Hammersmith displacing the most marginal trips on that bridge. That means not all local trips across Hammersmith bridge evaporated, but others did.  Again, this leads to a more efficient use of resources, with a reduction in marginal travel be car.It’s certainly true that local traffic that has been most affected by the closure, and half of the bridge traffic has indeed used the A4/M4/M25 - you can see an uptick in the traffic counts.  But that’s also a good outcome: it is far better for traffic to use the trunk network for longer trips than residential streets.Overall, it is difficult to see many willing to pay at least £4 each way to regain car access to Hammersmith Bridge. The  mood in Barnes has definitely shifted as the benefits in terms of reduced traffic have become apparent without the dire economic consequences to local businesses that some predicted.

Tom Pike ● 1432d

I'm beginning to doubt myself, but I thought that roads that have traffic jams have MORE cars than the same road without a traffic jam.The flow of cars is roughly the same, but because there are too many cars, it causes tailbacks and it takes longer for everyone to get past the point measured by a camera.So a road that is at full capacity - say 2000 cars per lane per hour - will still allow 2000 cars per lane per hour even if there are 4000 cars, it will just take twice as long.I think Bill is suggesting the exact opposite.  That once you reach full capacity on a road, the flow of cars falls.  From the perception of the driver that might feel like that is the case - how can there be the same number of cars flowing per hour when it feels like the traffic is stationary.  In complete gridlock, hardly any cars can be moving.  I would have thought that the traffic cam could count the number of cars though to fairly easily prove this one way of the other.But the second principle I've seen Bill and others state is that traffic cams cannot count cars in gridlock - I assume because if the cars are moving slowly, it cannot distinguish between moving and parked cars? 

Ed Saper ● 1432d

Tom, can you clarify why you say Hammersmith Bridge is a residential street? Castlenau is the A306 and a wide road with a bus lane. Some residents may be delighted its now traffic free but then others on roads such as Lower Richmond Road & Mortlake High St now suffer more queues and pollution. Some days the queue stretch almost back to Barnes bridge.So from an emissions/ climate perspective is it better for traffic to be taking a long diversion via M25/ M4 than by far the most direct route?YOu say that businesses in Barnes seeing more taking is commendable, but what about the other business that now dont have that custom? Or are you saying that if we close all roads the economy and consumer spending magically gets bigger? Of course its quite hard to take COVID and other factors out of the equation.We have very few bridges in London, they are a critical part of the transport infrastructure. They were not built as nice places for middle class professionals to go for a stroll. In fact they can perfrom both functions perfectly well. Your post is full of the most astonishing generalisations.

Bill George ● 1432d

Ed, yes the flow of vehicles falls. We see a perfect example with the A4 now. Its not the number of vehicles but the capacity of the road. So we see ver clearly that you close 2 out of 3 lanes on the A4 and the capacity of that road falls dramatically. So the number of cars able to pass every hour is down, in fact by more than two thirds due to traffic slowly filtering into a single lane. It is a physical impossiblility for the same number of vehicles to use the A4 as before, outside of the limited off peak period or throgh the night.A traffic counter merely counts the number of vehicles passing a set point. If for whatever reason fewer vehicles cross that point ina  given time period, then the counter merely records fewer vehicles.Without being too simplistic traffic is often a misleading term. Does it mean the amount of congestion or the number of vehicles using a road. They are two very different things,This then has knock on effects as other junctions become gridlocked. Think of SCR southbound, even without the reduced green phase. This can then block back to Heathfield Terrace, delaying both west and eastbound traffic on this road. Or CHR westbound down towards Chsiwick rounabout which also is solid for many hours of the day.

Bill George ● 1432d

People who use stats to further their argument know all about these little tricks and use them whenever they can.  Who does that help?

Maggie Dodge ● 1432d

It’s called fake news 😂😂😂

Jayne Thorburn ● 1432d

"Ed, yes the flow of vehicles falls."If the A4 can carry e.g. max 6,000 cars per hour past a camera over 3 lanes, then reducing to 1 lane should reduce max capacity to 2,000 cars per hour.If pre-lane closure, the A4 carried only 2,000 cars per hour, then it shouldn't make much difference going down to one lane.  If the A4 carried 4,000 cars per hour over 3 lanes, then it would take roughly twice as long for a car to travel down a one lane stretch.Correct me if I'm wrong, but I thought you were suggesting that reducing the lanes from 3 to 1 also reduces the capacity of the lane as well?  e.g. instead of being able to carry a max of 2,000 cars per hour, it can only carry, say, half that amount."It is a physical impossiblility for the same number of vehicles to use the A4 as before"I don't see how that can be the case.  The same number of vehicles can use the A4, but it will take longer for them to get through if the road was already at capacity during peak times.  The peak time would last longer.People might choose not to travel down the A4 during that time because of the length of time it takes - either displacing to other roads or choosing not to make the journey by car, going to a different destination or cancelling the trip. 

Ed Saper ● 1432d

Tom, ambulances, fire engines, police, buses, vets deliveries, etc  do they also evaporate?Remind me, how many individuals constituted your contention that the majority of people wanted the bridge closed to vehicles? This being extrapolated from a survey of how many people?

Adrian Irving ● 1431d

So with a constricted road, while the measured traffic flow at a point might appear to be reduced, the same volume of traffic might still exist but take longer to pass that point. So the graph will be flatter but wider. Another factor is that slower moving vehicles can travel closer together and thus increase the capacity of the road, hence adjustable speed limits on motorways, which also reduce bunching. The reduction ad absurdem of this is that the greatest road 'capacity' is achieved when the traffic is stationary!

Peter Evans ● 1431d

Ed, I fear we are heading down a black hole here. yes the capacity of the one remaining lane falls sharply as traffic filters into it, so the average speed in the one remaining lane falls hugely. So the new capacity is well below the 2000 you state. I am sure fluid flow model can give more exact numbers, but its well more than half less. You also assume lots of space capacity on the A4, at peak times this was evidently not the case, and is not for much of our trunk network.The reality is that people dont just sit for 3 hours to make a journey that they expect to take 30 minutes. And the broader spread of congestion means that even more traffic cannot reach the A4 nor complete journeys on routes well away from the A4.Let me pose the question a different way. If closing two lanes makes no difference why is much of W4 and CHR eastbound near gridlock for long periods of the day?

Bill George ● 1431d

Thanks Bill. So your position is that once a lane reaches normal capacity, that capacity is then more than halved. So at 2k cars per hour capacity, if there were 4K of cars trying to get through, a lot fewer than 1k could do so. I’ll have a look later to see if there are any studies that confirm this. Feel free to post what you have.

Ed Saper ● 1431d

In theory, because of the halved stopping distance between each vehicle, two lanes of traffic doing 60mph can fit into one lane doing 40mph, and so on.

Peter Evans ● 1431d

Ed, afraid I have reached a limit on the topic, I am sure I am not explaining very well but its not that hard a concept, I think you are overanalysing. I would again pose a very simple question to you, why has much of W4 faced gridlock over last month, especially heading westbound? Also go and stand by the roadworks and watch how the traffic slowly filters into one lane from three. Consider how the congestion spreads out from the A4 to all surrounding routes. If every single person who normally uses A4 and surrounding routes is willign to sit in a jam for 2-3 hours for a journey that might normally take a fraction of that time, then sure over a 24 hour perioud you might just about get the same traffic flow. But then the congestion would simply last longer, expand over a wider period, and the quiet periods shorter, so in practice that wont happen.If your simple position is true then why would any traffic need to divert from the A4? Why would the A4 at times queue back to the Hammersmith flyover?

Bill George ● 1431d

You are misapplying the reduction in capacity of closing lanes on the A4 (which will certainly reduce the maximum hourly flow) as an explanation for the lack of an increase on the neighbouring bridges. But the neighbouring bridges did not have lanes closed, so it doesn't provide the explanation you are hoping for. You are not going to see a reduction at the DfT estimates at the Borough Level for the removal of traffic from Hammersmith Bridge - the change is much smaller than the uncertainties in the estimates, which are dominated by inferred minor-road traffic. However, it is possible to test your hypothesis that the bridge traffic simply rerouted along local roads as then we would expect to see a significant climb in their traffic, as measured by the actual DfT road counts. That is a much more sensitive test.We have three nearby locations with actual counts before and after the closure, on Upper Richmond Road, east and west of Barnes, and on Station Road in Barnes. Station Road links Barnes High Street with Lower Richmond Road. It shows no significant increase after the closure - in fact the traffic counts are lower than the average of the previous five years, so your hypothesised traffic seems to have bypassed that street for some reason. Similarly, if you look at automatic counts to the west on Upper Richmond Road, which you claim has been badly affected as a result of the closure, there was only a small  increase with the closure of 1600 vehicles in North Sheen, less than 10% of the 22,000 that was using Hammersmith Bridge. Similarly if you look to the east, on Upper Richmond Road in Putney, traffic counts increased by only 600 with the closure. Both changes are comparable to the annual variation at those two locations.Therefore you hypothesis that most of the local traffic has diverted to other roads is not supported by the traffic measurements on all three of the nearest count points.

Tom Pike ● 1431d

You are omitting that vehicles have a finite length! In fact road capacity, in terms of vehicles an hour, is in practice more or less independent of speed above 20 mph, and falls rapidly below that speed.

Tom Pike ● 1431d

Again, your hypotheses are not supported by data. The latest High Road traffic counts show that since August westbound traffic levels are indeed rising earlier in the day, peaking later and staying higher longer into the evening. Any consistent observer of the traffic in W4 would confirm this.

Tom Pike ● 1431d

Capacity of a road is usually defined in terms of vehicles per hour so the number of vehicles passing a given point during the time period.  If the vehicles are stationary during this period then the capacity in terms of vehicles per hour will be zero, so the least capacity, not the greatest!Capacity in terms of the number of vehicles that can be accommodated when they are stationary usually applies to car parks rather than roads.

Michael Robinson ● 1431d

I've posted about this separately but there is no listing of the planned closure on the roadworks.org site which could mean that it has been cancelled due to the A4 project overrun. If this is the case Ealing Council appear to believe it is a state secret.

Mark Evans ● 1429d

I found this. Hard to believe it refers to the same thing; "delays unlikely" though there's a caveat about Ealing Council's use of the actualité.

Bruce Hammal ● 1429d

I’m pretty sure the cycle lobby will be informed and will share with us eventually. They always seem to be one step ahead. Possibly they are part of the decision making, who knows

Maggie Dodge ● 1429d