What effect could improved rail services have on M4 congestion?

[Rhydgaled]

So, it seems the Welsh Government (in their infinite wisdom:roll want to build a new motorway around Newport (there's currently a 'consultation' where all the options seem to be some form of major new road) between junctions 23a and 29. And the Welsh Government claim to be 'green'????

There seem to be two objectives, easing congestion on the M4 around Newport and providing a Brynglas tunnel diversionary route. The proposed new road options seem like complete overkill for the latter aim, given they recently built the 'Steelworks Access Road' dual carriageway which runs from M4 junction 23a to the A48. Therefore, I would suggest a Brynglas tunnel diversionary route could be created with improvements to the A48 (or a new dual-carriageway if necessary) from the point where the Steelworks Access Road joins the A48 to either junction 28 or 29 of the M4. I would imagine this would come at far lower cost than another new road which would unecessarily duplicate the 'Steelworks Access Road' for some distance.

That leaves the other aim of reducing congestion. Doing so by building more road capacity will just create more traffic and more climate change. So, can public transport in general and rail in particular generate enough modal shift to solve the problem? Where does the traffic come from and why doesn't it use rail? What rail improvements would capture enough of the traffic (I know one I'd suggest, but I don't know if it'd do any good)?

 

[RichmondCommu]

The car will always be more convenient than the train, nothing we can do about that. What we need to try and do is take more freight off the roads.

 

[Eagle]

Doing so by building more road capacity will just create more traffic and more climate change.

This is false and there is no evidence that shows it.

Lowering congestion will lower overall emissions as traffic will be moving faster. And you can't deny that Brynglas is a horrible bottleneck.

As an aside, this road has been proposed since about 1998 (in fact I have a road atlas from 2004 that actually shows it under construction). I don't know why it's taking so ridiculously long to decide whether or not to build it.

 

[The Ham]

This is false and there is no evidence that shows it.

Lowering congestion will lower overall emissions as traffic will be moving faster. And you can't deny that Brynglas is a horrible bottleneck.

As an aside, this road has been proposed since about 1998 (in fact I have a road atlas from 2004 that actually shows it under construction). I don't know why it's taking so ridiculously long to decide whether or not to build it.

OK, how about they've built the Hindhead Tunnel and now there is even more demand for Guildford to have impovements to it's section of the A3.

Or take Newbury it has now been by-passed twice because fo te amount of traffic.

If they are too subtle for you, how about the M25, it was built the local roads became freed up, untill the M25 was full, then they built a 4th lane and that and the local roads are still full.

Yes they are all examples in the SE, however over time it is the case with any major road building scheme that by building it the problem just moves along the road a bit and/or more traffic is created to fill the road space.

 

[gordonthemoron]

removing one bottleneck will result in a bottleneck elsewhere

 

[pablo]

The A48 is a local distributor. Doesn't tackle the problem.

What would you like to do? Run a Park and Ride from Jct 23 to Jct 29? :roll:

 

[DynamicSpirit]

This is false and there is no evidence that shows it.

Lowering congestion will lower overall emissions as traffic will be moving faster. And you can't deny that Brynglas is a horrible bottleneck.

As an aside, this road has been proposed since about 1998 (in fact I have a road atlas from 2004 that actually shows it under construction). I don't know why it's taking so ridiculously long to decide whether or not to build it.

It's possible that if congestion is reduced, that may mean that the emissions resulting from a single individual journey may go down (though if a new road is built at motorway speeds, that may be counterbalanced because most cars become less fuel efficient above - last time I checked - between 40 and 60mph depending on the car).

However simple economic theory of supply and demand (as well as just about all previous experience building new roads in the past) tells you that if you make it quicker or easier for people to drive, more journeys will very likely be made by car. I think you can be very certain that that will more than offset any reduction in greenhouse emissions from individual journeys being more efficient.

 

[tbtc]

Funny how we use the "if you build it, they will come" argument to justify railway investment, but the same argument becomes A Bad Thing when used on the roads - the same things apply - getting rid of a railway bottleneck will just create one further up the line, yet we still want to get rid of railway bottlenecks.

As for the OP, I really can't see the WG spending much money on proper railway improvements. The money that they have allocated to transport seems to be focussed on road (the "head of the valleys" route etc), air (Cardiff Airport, the Holyhead - Cardiff flights), buses (fast buses to Cardiff Airport for those arriving from Holyhead)...

...what railway investment there has been (from the WG) seems to be tinkering at the margins (Fishguard, a "premier class" train with a restaurant for the Holyhead route). I really don't see the WG as being "green" and therefore don't see why some people believe that giving them more powers will encourage more rail investment.

 

[tony_mac]

even if the traffic doesn't go up, building new roads can actually increase congestion (admittedly, a fairly rare thing in practice).

http://www.oasys-software.com/blog/2012/05/braess%E2%80%99-paradox-or-why-improving-something-can-make-it-worse/

 

[DynamicSpirit]

Funny how we use the "if you build it, they will come" argument to justify railway investment, but the same argument becomes A Bad Thing when used on the roads - the same things apply - getting rid of a railway bottleneck will just create one further up the line, yet we still want to get rid of railway bottlenecks.

That's very true. I think the difference though is that travelling by train is a relatively benign form of transport (not in absolute terms of course, but in the sense of being much less harmful than making the same journey by car - in many cases, the main competitor - would be.).

When you improve or build a road, you make it easier for people to travel by car. That has some beneficial impact in terms of increasing people's freedom. It also comes with all the usual adverse consequences - pollution, possibly increased congestion on all the roads that feed into the new road, etc. And - worse - it will generally encourage some people to switch from bus or train to the car, which not only exacerbates the environmental harm but can start a vicious circle where it becomes harder to provide adequate public transport for the remaining people who still wish to use it. It even may do things like reduce the viability of small local shops (because more people are using the road to travel to the superstore 5 miles away instead, resulting in local shops closing). In most cases that adds up to a lot more harm than good overall.

When you improve or build a railway, you make it easier for people to travel by train. Again there's some beneficial impact in terms of increasing people's freedom. And there are some adverse consequences - more pollution etc. (but crucially, not nearly as much as if those extra journeys were made by car). And now, the effect of encouraging people to switch modes of transport becomes a good thing: Some people will swap from car to train, which is an environmental benefit (some will swap from bus to train, which is probably more neutral). The greater use of public transport may make it more viable to provide yet more additional public transport services. It's much less likely to impact the viability of small local shops. So it's not hard to see that in most cases with the railway you're probably going to do more good than harm.

 

[soil]

OK, how about they've built the Hindhead Tunnel and now there is even more demand for Guildford to have impovements to it's section of the A3.

Journey times are now vastly improved on the A3 due to the tunnel, and traffic (e.g., me) that would otherwise go via the M3 is now taking the A3.

The traffic moves from other roads. It's good for emissions, since rather than taking a diversion, or sitting in traffic on the old tunnel, you can now take a more efficient route.

If they are too subtle for you, how about the M25, it was built the local roads became freed up, untill the M25 was full, then they built a 4th lane and that and the local roads are still full.

I'm not sure what your point is here.

There are places in the world where road-building has been less than around the M25, and the gridlock is much worse.

Correlation doesn't prove causation at all.

The London area is very densely populated and for that reason the roads are full.

 

[HSTEd]

Saying that people having more freedom to move about the country is bad is very dodgy in my opinion.

Sure, build the road, but also build a South Wales Shinkansen to try and capture a fraction of the passenger transport market in the corridor.

 

[impster]

Don't forget that motorway conjestion was created by the building of the motorways...

 

[andykn]

Funny how we use the "if you build it, they will come" argument to justify railway investment, but the same argument becomes A Bad Thing when used on the roads - the same things apply - getting rid of a railway bottleneck will just create one further up the line, yet we still want to get rid of railway bottlenecks.

That's because you're not trying to restrict people's travel but to get them to travel in the easiest way to accommodate. More people travelling by car often isn't viable because you don't have the physical space for the cars where they want to go, most often city centres. It's easier to build transit systems in cities to move people from the rail heads instead of demolishing the buildings they've come to visit so they can park their cars.

 

[The Planner]

Don't forget that motorway conjestion was created by the building of the motorways...

And congestion on the railways is created by wanting to run more trains....

 

[Bald Rick]

What improvements to the rail service in the Newport, Cardiff, SE Wales area would have the effect of reducing congestion on that section of the M4?
(Genuine question, I really don't know!)

 

[HowardGWR]

The car will always be more convenient than the train, nothing we can do about that. What we need to try and do is take more freight off the roads.

It isn't if you are stuck in a queue or have to pay a large amount to use the road. The only reason that most commuters into London (? I just wonder about that actually) do not use the car, is because it is physically and financially impossible.
--- old post above --- --- new post below ---

This is false and there is no evidence that shows it.

Lowering congestion will lower overall emissions as traffic will be moving faster. And you can't deny that Brynglas is a horrible bottleneck.

As an aside, this road has been proposed since about 1998 (in fact I have a road atlas from 2004 that actually shows it under construction). I don't know why it's taking so ridiculously long to decide whether or not to build it.

It isn't false until you produce your detailed fact-supported analysis.
--- old post above --- --- new post below ---
@Rydgaled
Your options were not sufficiently comprehensive, none of them could I vote for, sorry .

I have also just realised you have put this in the wrong section, it should be in Infrastructure.

 

[RichmondCommu]

When you improve or build a road, you make it easier for people to travel by car. That has some beneficial impact in terms of increasing people's freedom. It also comes with all the usual adverse consequences - pollution, possibly increased congestion on all the roads that feed into the new road, etc. And - worse - it will generally encourage some people to switch from bus or train to the car, which not only exacerbates the environmental harm but can start a vicious circle where it becomes harder to provide adequate public transport for the remaining people who still wish to use it. It even may do things like reduce the viability of small local shops (because more people are using the road to travel to the superstore 5 miles away instead, resulting in local shops closing). In most cases that adds up to a lot more harm than good overall.

Why do you think people choose (where they can) to travel to out of town superstores? The simple reason is price and availability and in particular price. When times are hard the physical cost of something is more important to the individual than anything else. There are many journeys made all over the UK where it is not feasible to use public transport let alone the train. We should not be making it harder for people to use their cars in order to force them to use the train. Individuals should have a choice as to which mode of transport they choose to use.
--- old post above --- --- new post below ---

It isn't if you are stuck in a queue or have to pay a large amount to use the road. The only reason that most commuters into London (? I just wonder about that actually) do not use the car, is because it is physically and financially impossible.

In terms of commuting into London then yes I agree with you. However South Wales is very different to London.
--- old post above --- --- new post below ---

I have also just realised you have put this in the wrong section, it should be in Infrastructure.

Give it six months and you'll be running the forum.

 

[Gareth Marston]

The basic issue is the mega congestion whenever there's an accident on the Brynglas tunnels section ( 2 lanes) no hard shoulder. Essentially a duplicate motorway is deemed neccesary in case of accidents. The same thinking is being used by "business leaders" about the A55 expressway along the north Wales coast we need a duplicate so traffic keeps flowing. The logical conclusion is that the wanted solution of duplicate main roads everywhere is totally unaffordable and will never be built

 

[DynamicSpirit]

Saying that people having more freedom to move about the country is bad is very dodgy in my opinion.

I agree with you. However as far as I can tell no one on this thread has said anything like that (or have I missed something)? So I'm somewhat puzzled as to why you posted that comment. What was it in reply to?
--- old post above --- --- new post below ---

removing one bottleneck will result in a bottleneck elsewhere

In this context, the specific proposal being discussed - as far as I understand it - is a new road to relieve congestion on a motorway bottleneck.

Strangely, not too long ago, a new road to relieve capacity along that same motorway *was* provided a little bit to the East - the 2nd Severn Crossing. So this does look superficially like a classic case of what you are describing: Providing capacity to remove one bottleneck did in fact cause (or maybe in this case: exacerbate) a bottleneck further along the road.

 

[tbtc]

The basic issue is the mega congestion whenever there's an accident on the Brynglas tunnels section ( 2 lanes) no hard shoulder. Essentially a duplicate motorway is deemed neccesary in case of accidents. The same thinking is being used by "business leaders" about the A55 expressway along the north Wales coast we need a duplicate so traffic keeps flowing. The logical conclusion is that the wanted solution of duplicate main roads everywhere is totally unaffordable and will never be built

I've seen a lot of people justify electrification of railway lines for diversionary purposes (including lines that see basically no passenger service), for similar "duplicate" reasons.

 

[pablo]

......In this context, the specific proposal being discussed - as far as I understand it - is a new road to relieve congestion on a motorway bottleneck.

Strangely, not too long ago, a new road to relieve capacity along that same motorway *was* provided a little bit to the East - the 2nd Severn Crossing. So this does look superficially like a classic case of what you are describing: Providing capacity to remove one bottleneck did in fact cause (or maybe in this case: exacerbate) a bottleneck further along the road.

and that's the trouble with superficiality. Is there any demonstrable correlation between the two?

 

[GearJammer]

The car will always be more convenient than the train, nothing we can do about that. What we need to try and do is take more freight off the roads.

Change the record..... its nearly christmas, ask santa for a new one!

If you think removing freight off the road will cure the problem then your clearly just not thinking and passing the blame (of congestion) onto someone else because you don't want to admit YOU are adding to the problem sitting in your car, if you don't like seeing freight on the road then use the train.... oh no sorry, won't do that will you because you much prefer somebody else to change the way they do things so you don't have to.

 

[Llanigraham]

Strangely, not too long ago, a new road to relieve capacity along that same motorway *was* provided a little bit to the East - the 2nd Severn Crossing. So this does look superficially like a classic case of what you are describing: Providing capacity to remove one bottleneck did in fact cause (or maybe in this case: exacerbate) a bottleneck further along the road.

No, because the Brynglas Tunnels have been a bottleneck ever since they opened 30+ years ago. The 2nd Severn Crossing has made no difference.

 

[doubletrackemble]

I don't think there's any serious alternative to a new M4 to the south of Newport. Tinkering with upgrades to the A48/Steelworks Access Road is not going to solve matters, and no feasible rail improvement options could deal with the diverse origins/destinations of M4 users. Hopefully this time the project will be followed through, and not dropped again.

 

[Llanigraham]

Quite!!

 

[aleph_0]

Why do you think people choose (where they can) to travel to out of town superstores? The simple reason is price and availability and in particular price. When times are hard the physical cost of something is more important to the individual than anything else. There are many journeys made all over the UK where it is not feasible to use public transport let alone the train. We should not be making it harder for people to use their cars in order to force them to use the train. Individuals should have a choice as to which mode of transport they choose to use.

But the original topic wasn't about an intervention to make it harder for people to use their cars. It was about whether instead of one intervention (bypass brynglas tunnels to improve motorway capacity), one might be better off investing in other interventions (rail capacity).

In general, one needs to remember that the designing of infrastructure influences how convenient each mode of transport is. Money spent on M4 Newport Relief is money not spent elsewhere. A pedestrian crossing makes walking safer, but adds time to a motorist's journey. A staggered pedestrian crossing synchronised with a junction minimizes impact on the motorist, but delays a pedestrian.

It's reasonable, then, to ask the question of whether it would be better to instead to implement other improvements to reduce traffic. In this case, rail. Previously the A4042 was improved partly motivated by the idea of removing valleys-bound traffic from the tunnels.

As tbtc hinted, it would be doublethink to not acknowledge that rail has similar issues. I agree, one should look at rail improvements with a similarly open mind. There's nothing wrong with increasing capacity and removing bottlenecks, as long as one realise that it's not as obvious as "have bottleneck, must remove", as one will always hit a capacity constraint.

 

[Gareth Marston]

Given thecurrent M4 relief road is estimated at £100 million a mile to construct a few miles of wired diversionary route at a couple of million £ a mile is very favourable.

There's roughly 85 mile of M4 in Wales and nearly 100 of A55 expressway at these costs the duplicate roads are prohibitive to build.

 

[Deerfold]

Any particular reason the options don't include any that don't involve building more road?

 

[Rhydgaled]

The car will always be more convenient than the train, nothing we can do about that. What we need to try and do is take more freight off the roads.

The car will always be more convenient than the train, yes. But there other aspects to consider, where the train can beat the car, which in my opinion should, must even, be provided and promoted to reduce car use.

This is false and there is no evidence that shows it.

Lowering congestion will lower overall emissions as traffic will be moving faster.

Traffic will be moving faster, yes. And yesm if you just split the current traffic between the two roads it would lower the emissions a little. However, the fact the traffic will be flowing easier and faster will encourage more traffic, which will increase emmissions.

I don't know why it's taking so ridiculously long to decide whether or not to build it.

At least two of the new road options are listed as having severe biodiversity impacts. That and cost are probably two reasons not to do it.

As for the OP, I really can't see the WG spending much money on proper railway improvements. The money that they have allocated to transport seems to be focussed on road (the "head of the valleys" route etc), air (Cardiff Airport, the Holyhead - Cardiff flights), buses (fast buses to Cardiff Airport for those arriving from Holyhead)...

...what railway investment there has been (from the WG) seems to be tinkering at the margins (Fishguard, a "premier class" train with a restaurant for the Holyhead route). I really don't see the WG as being "green"

I agree, they aren't acting 'green' with regard to transport spending, it's nearly all car/lorry and air (I count the Cardiff Airport bus as more spending on air, not on buses, as it is reportedly only for travel to/from the airport).

When you improve or build a road, you make it easier for people to travel by car. That has some beneficial impact in terms of increasing people's freedom. It also comes with all the usual adverse consequences - pollution, possibly increased congestion on all the roads that feed into the new road, etc. And - worse - it will generally encourage some people to switch from bus or train to the car, which not only exacerbates the environmental harm but can start a vicious circle where it becomes harder to provide adequate public transport for the remaining people who still wish to use it. It even may do things like reduce the viability of small local shops (because more people are using the road to travel to the superstore 5 miles away instead, resulting in local shops closing). In most cases that adds up to a lot more harm than good overall. When you improve or build a railway, you make it easier for people to travel by train. Again there's some beneficial impact in terms of increasing people's freedom. And there are some adverse consequences - more pollution etc. (but crucially, not nearly as much as if those extra journeys were made by car). And now, the effect of encouraging people to switch modes of transport becomes a good thing: Some people will swap from car to train, which is an environmental benefit (some will swap from bus to train, which is probably more neutral). The greater use of public transport may make it more viable to provide yet more additional public transport services. It's much less likely to impact the viability of small local shops. So it's not hard to see that in most cases with the railway you're probably going to do more good than harm.

I agree, well said.

What improvements to the rail service in the Newport, Cardiff, SE Wales area would have the effect of reducing congestion on that section of the M4?
(Genuine question, I really don't know!)

I don't know either. Might help to have an answer to one of the questions in the OP:

Where does the traffic come from and why doesn't it use rail?

Your options were not sufficiently comprehensive, none of them could I vote for, sorry .

Sorry, what would you have said if the option was there?

I have also just realised you have put this in the wrong section, it should be in Infrastructure.

My thinking behind the topic was more what sort of rail service improvements could help, and how much they would help. Those service improvments may or may not require infrustructure enhancments, but this thread's more about the level of service needed, and perhaps the road infrustructure needed.

The basic issue is the mega congestion whenever there's an accident on the Brynglas tunnels section ( 2 lanes) no hard shoulder. Essentially a duplicate motorway is deemed neccesary in case of accidents.

Yes, to answer somebody else as well, I can't deny that Brynglas is a horrible bottleneck when something goes wrong. In my opinion though, that's not enough to warrant a duplicate motorway. If you shut one tunnel due to an accident, surely a dual-carriageway diversionary route is sufficient (as you'd still have 6 lanes, two (out of the four when all is well) at Brynglas and four on the diversionary route).

We already have a partial dual-carriageway diversionary route in the form of the steelworks access road, you just need to build the other half (either as a new road or by upgrading the A48).

no feasible rail improvement options could deal with the diverse origins/destinations of M4 users.

Diverse maybe, but are there any major entry/exit points? For example, is a large portion of the traffic using the M4 for a long distance, having joined west of Port Talbot and staying on the M4 until England? Or is there a large flow to Swansea from England?