Bus stops and bus lanes

[Mation]

I've noticed since I started cycling that loads of bus stops have two, long, rounded ridges that run parallel to the curb, about a metre apart from each other.

Why?

It's not the whole bus lane, just at the stops. This is around London, but perhaps also the case elsewhere?

Meant to take a picture earlier, but forgot. It's sort of like this, but more raised.

 

[BristolEcho]

I've noticed since I started cycling that loads of bus stops have two, long, rounded ridges that run parallel to the curb, about a metre apart from each other.

Why?

It's not the whole bus lane, just at the stops. This is around London, but perhaps also the case elsewhere?

Meant to take a picture earlier, but forgot. It's sort of like this, but more raised.

It's wear and tear from the buses coming in at that angle I think. Mainly I see it on really busy stops and particularly when they might idle there. Nightmare when you end up in it without meaning too. A lot of the roads near to the bus stop I normally see it on are fucked too and have to be relaid quite often, but not much can be done imagine.

 

[Saul Goodman]

That looks like the road is fucked. Probably from buses braking and pushing the tarmac under their wheels.

 

[Mation]

It's wear and tear from the buses coming in at that angle I think. Mainly I see it on really busy stops and particularly when they might idle there. Nightmare when you end up in it without meaning too. A lot of the roads near to the bus stop I normally see it on are fucked too and have to be relaid quite often, but not much can be done imagine.

In the above picture it looks like wear and tear, for sure. But that pic was more to illustrate the position of the ridges, rather than the state of the surface, which can be largely intact or newish-looking.

 

[Spymaster]

Can't say I've noticed them but I don't think they're supposed to be there.

 

[Puddy_Tat]

Yes - probably wear and tear

Buses have gradually got larger and heavier over recent decades (a 'boris bus' is 12 and a bit tons without passengers, the 72 seat version of the 'proper' routemaster was 7 and a bit tons), road maintenance has got progressively worse with funding cuts.

I'm not sure, but wonder if the effect of buses braking / accelerating / steering in and out of stops will cause more wear on the road surface than just moving along at a steady speed in a straightish line.

In some places, busier bus stops kept stone setts after tarmac surfaces became common, to be more hard wearing, although i guess this wouldn't be great for cyclists

 

[Mation]

In lieu of a photo (yet), here is a highly-accomplished diagram of what I mean, were you to be lying flat in the road at a bus stop, looking up a little bit, along the road ahead.



It probably needs no explanation, but that is the kerb, on the left.

 

[teuchter]

Tarmac is somewhat malleable especially in warm weather. When a lot of heavy vehicles with the same distance between wheels do the same thing at the same place, over and over, it deforms the tarmac.

You see this especially at bus stops on hills where the wheels exert a lot force on the road surface when they start or stop.

 

[Mation]

Can't say I've noticed them but I don't think they're supposed to be there.

I'd never noticed them at all before, either. I guess because I don't cross the road at bus stops, or the bus is at the stop and hiding them.

Tarmac is somewhat malleable especially in warm weather. When a lot of heavy vehicles with the same distance between wheels do the same thing at the same place, over and over, it deforms the tarmac.

You see this especially at bus stops on hills where the wheels exert a lot force on the road surface when they start or stop.

Wouldn't that cause dips, rather than raised bits, with the surface in between and either side being flat?

 

[teuchter]

I'd never noticed them at all before, either. I guess because I don't cross the road at bus stops, or the bus is at the stop and hiding them.

Wouldn't that cause dips, rather than raised bits, with the surface in between and either side being flat?

I'd guess in your diagram wheels are constantly moving sideways towards the kerb, pushing the ridges like that because at a certain point they stop moving any further to the left. So the wheels run just to the right of the ridges when the bus comes to a stop.

 

[teuchter]

You sometimes see it at traffic lights on heavily trafficked roads with a lot of HGVs too. Then there are more likely waves perpendicular to the roadway.

 

[Mation]

I'd guess in your diagram wheels are constantly moving sideways towards the kerb, pushing the ridges like that because at a certain point they stop moving any further to the left. So the wheels run just to the right of the ridges when the bus comes to a stop.

Aha! That could be it.

I'll try to remember to take a pic tomorrow. Walworth Road is particularly bad, which would make sense given how many buses run along it.

 

[BristolEcho]

I also suspect that bus drivers naturally drive into those slots continually once the general line is formed?

 

[StoneRoad]

Wear and tear on tarmac that isn't up to the job, escpecilly worse in areas that get overheated by sunlight.

The buses all take about the same line so once the dips start, they are a point of weakness and the situation just gets worse.

One partial solution is to plant a line or three of wood blocks between the curbstones and the tarmac. The wood gets compressed by the weight but expands again when the load is removed. It lasts quite well, but fitting the wood is harder than laying new tarmac.

A similar thing happens in lane one on urban motorways, due to the weight / number of HGVs. That is only cured by relaying the road surface from the top down to the main weight bearing layer.

 

[RubyToogood]

The sudden sinking feeling is disconcerting when you go over one on two wheels.

 

[WouldBe]

I'd guess in your diagram wheels are constantly moving sideways towards the kerb, pushing the ridges like that because at a certain point they stop moving any further to the left. So the wheels run just to the right of the ridges when the bus comes to a stop.

If it was down to the weight of the bus wouldn't it create a double hump for each wheel as the tarmac would be pushed out to both sides of each wheel?

 

[Orang Utan]

I’ve always wanted to know why so many bus shelters in South London have VHS copies of Hellraiser on their roofs.

 

[teuchter]

If it was down to the weight of the bus wouldn't it create a double hump for each wheel as the tarmac would be pushed out to both sides of each wheel?

I am thinking that the bus wheels are exerting a sideways force on the surface of the tarmac, either because of the turning motion they are making as they approach the bus stop or maybe even because of a slope to the roadway. I believe the layers that make up the road surface can slip over each other and it's this which can cause the distortions rather than purely the weight pressing downwards depressions into it. But I'm not an expert on any of this.

 

[Mation]

I am thinking that the bus wheels are exerting a sideways force on the surface of the tarmac, either because of the turning motion they are making as they approach the bus stop or maybe even because of a slope to the roadway. I believe the layers that make up the road surface can slip over each other and it's this which can cause the distortions rather than purely the weight pressing downwards depressions into it. But I'm not an expert on any of this.

So it might be worse on wider roads?

 

[Bahnhof Strasse]

Can't say I've noticed them

You will now though, you won't be able to pass a bus stop without looking and seeing from now on. And it will bug the fuck out of you. All Mation's fault.

 

[Spymaster]

You will now though, you won't be able to pass a bus stop without looking and seeing from now on. And it will bug the fuck out of you. All Mation's fault.

Already done. I went for a run this morning and checked out every bus stop I passed. It's not a phenomenon that we seem to suffer in Camden, Chalk Farm/Primrose, Swiss Cottage, Kilburn, or St Johns Wood.

I'm therefore of the opinion that it's a South London thing. Perhaps bus passengers are heavier that side of the river?

 

[StoneRoad]

I've seen these "tramlines" at a number of bus stops in Tyne & Wear, especially at the stops in Newcastle where buses "wait time" (these days, that usually for a crew change or a fitter / inspector visit rather than timetables per se).
Several have been where the bus has to pull away up a slope.

 

[pseudonarcissus]

There’s a whole field of academic study. Apparently the correct term is “rutting”.

“Permanent deformation in asphalt pavement structures is one of the main pavement distress problems. The common asphalt pavement surface deformations are shoving and rutting at intersections, bus stops and line, in heavy vehicle loaded urban streets, where it is acceleration, deceleration, slow moving or static loading. Considering the occurred asphalt pavement layer rutting can be described as wear, structural and flow rutting. Recently, was observed the increase in severity and extent of rutting (the depth is 40 mm and more) in asphalt pavement structures in Vilnius city high-streets, bus lines and stops. The purpose of this research was to establish probabilistic (rutted) pavement structures in Vilnius city and to suggest the best treatment solutions. It was found that in many cases the failure was caused by asphalt layers fatigue and low resistance to flow rutting.”