Road humps

[AndyB]

And we wonder why residents think rat runs are being used as racetracks and why drivers aren’t trusted to drive according to the conditions...! More seriously, though, even the incompetent drivers will have been thus slowed down to an average speed of about 15mph because of the time wasted braking far harder than is necessary or desirable.

In all honesty, I would expect every rat run left to be equipped with humps in the next few years to discourage through traffic from going anywhere near it.

[Chris Bertram]

Which is all very well until a route that is a recognised through route - and not all such are classified roads - attracts, with very flimsy justification, the label "rat run" and the humps that go with that. My own road is one such, being part of the direct route from Edgbaston to Hall Green and Shirley. It links A435 with B4146 and then A4040, and traffic using it no longer contributes to the jams that often plague Kings Heath High Street, which would be the route if you stuck to numbered roads. We knew it was a through route when we moved here, it didn't put us off. But there are humps galore now, and not just near the primary school.

Has it deterred traffic? Not so as you'd notice. Has it slowed traffic down? Probably, but is that a benefit or a disadvantage? It wasn't clear that vehicle speeds were excessive before. What it definitely has done is increase noise as laden vehicles go over the humps, and increase building vibration when heavy vehicles traverse the s0dding things. And of course emergency vehicles are slowed down too. Finally, the humps - brick affairs set into the carriageway rather than lumps of tarmac - are poorly maintained, and the road surface around them tends to break up.

As you can tell, I'm not a fan. But you have to gather a lot of people together to form a campaign to oppose them, and generally people just don't care enough.

Incidentally, I discovered today that Birmingham City Council has a "Senior Transportation Officer – Transportation Behaviour Change". Frankly, transportation - in a very old sense - is the only thing appropriate for anyone occulying such a post.

[Truvelo]

I'm sure if the Kings Heath tunnel had been built it would have captured all north-south traffic using side roads to avoid the High street. And that is the crux of the problem. Installing humps is the cheap and nasty way of solving ratruns whereas removing bottlenecks from main roads is the ideal if costly solution.

My real hate is humps on A roads which can hardly be described as ratruns. The A713 at Dalmellington has them and to avoid them actually involves ratrunning along B roads and estate roads.

[Ruperts Trooper]

So why do so many speed humps cause damage if driven over at the speed limit - something isn't right somewhere!

Totally agree, how can it be correct that you take a perfectly flat piece of serviceable road and and deliberately place physical obstacles that prevent the road from being used at the posted speed limit. The particulate pollution caused by the accelerate and brake driving style that humps encourage is ignored by by those who put humps in place. And if you do adopt a steady safe speed to navigate humps you certainly suffer the wrath of impatient drivers... there are no winners with speed humps ...

Actually, the accelerate and brake style incurs my wrath because it is so significantly quicker to drive down such a road at a steady 20mph (allowing for easing off a little before humps) than to accelerate and brake, which inevitably sees me held up by people who think humps fit for 20mph running must be taken at 5mph.

The real answer is cost. Stick a few road humps down, you get a de facto speed limit of 20mph without the hassle of the legislation required for a 20 zone and without the lack of police enforcement.

I realise that this is not going to be a popular opinion, but the placement of road humps usually means there is a good reason (unrelated to engineering) not to be driving at 30mph, and if they were replaced by a 20mph speed limit with no traffic calming, the limit would simply be ignored due to lack of enforcement - and the point, which is usually to discourage rat running, is completely lost.

Most of the roads I use with humps are urban main roads, not rat-runs - even accepting the point of reducing the effective limit to 20 mph, many of these would cause severe discomfort and/or vehicle damage at that speed.

From my driver's seat, the problem is the ramp angle being too steep and applies to humps and tables - but cushions are largely ineffective with all but the narrowest of cars being un-troubled by them.

[avtur]

....More seriously, though, even the incompetent drivers will have been thus slowed down to an average speed of about 15mph because of the time wasted braking far harder than is necessary or desirable....

I've never witnessed that, the incompetent drivers in my book are those who don't make any attempt to slow down and simply continue whatever the consequences. You would no doubt blow a fuse if you followed me over humps, my only concern is damage to my car and I'll slow down as much as I deem necessary to ensure my car is not damaged. On all other roads my thoughts about speed are somewhat different.

[darkcape]

The road I live on is a rat-run, acting as a left-turn bypass of a signalised roundabout. It had some work done some ten years ago where speed tables were installed at the entrance and exit to the main roads, and made part of it one-way - but in the direction of the rat-run.

My old house was in a council estate where all the roads had humps. I find drivers seem to respond to a few humps at key locations, whereas the estate had a lot of accelerating and braking between humps as there were so many.

[Benny]

Speed humps (IMO) have had their day and do you know why?

SUVs.

The crims nick an X5/Range Rover/ Land Cruiser etc and they are unstoppable, they can bounce over most of them without even noticing. The yummy mummy brigade are at it too with their PCP'd Evoques generally bought by the baby daddys....

Chris Bertram-I know the area you refer to, from when my sister lived in Moseley and I was actually road raged by a man in a dirty old Transit van on a part of that road because I was forced to take the bumps very slowly as my car at the time was a very low slung Fiat Coupe. He gave me a very hard time and then performed an outrageous overtake. WMP did not wanna know.

[FosseWay]

The real answer is cost. Stick a few road humps down, you get a de facto speed limit of 20mph without the hassle of the legislation required for a 20 zone and without the lack of police enforcement.

You get a de facto *average* speed of 20, yes, but that can hide large variations between, say, 40 and 10. All of the safety concerns that lead to roads having speed limits of less than 40 in the first place are still very much an issue between the humps, to which can be added the possibility of drivers being more attentive to the coming hump than to an errant child or other potential victim.

Also - I keep banging on about this, I know - car drivers are not the only users on the road. There are two buses from me to town; one goes along the "happy car" road at 90 km/h and the other winds up through the coastal villages. The latter takes longer, naturally, but it is also extremely uncomfortable because of all the humps. The nature of the road (many right-angled bends, give ways etc.) and the fact the bus has to stop at bus stops means that with or without the humps it is unlikely to exceed the posted limit and is usually going slowly enough to keep up with on a bike. And yet luggage goes flying and people bounce in their seats on every hump. This effect could of course be reduced by getting the bus drivers to drive more slowly. How slow is "appropriate"? Is it really tenable to get all motor traffic on through routes to drive at an average of under 20 mph? How slow do we have to get before society decides that increased travel time and discomfort is out of all proportion to any safety benefits?

I'd also like to see some definitive evidence that installing humps reduces casualties. Most of the time when there's any follow-up coverage in the press after installation, the council spokespeople trumpet that it's been a great success because average speeds have dropped from x to y. That is not "success"; that is failure, pure and simple, without any evidence of improved accident statistics, and it tends to reveal a frequently encountered attitude that speed in itself is bad. No, it isn't. If people can get to work faster, if goods can be delivered faster, we all benefit from the economic improvements of that. We control speed on the roads not because we want people to go more slowly as an end in itself, but because higher speeds are generally associated with more and worse collisions. But if any given reduction in average speed doesn't actually lead to an improvement in casualty rates, then it is worse than worthless. But we never know one way or the other.

[Chris Bertram]

Chris Bertram-I know the area you refer to, from when my sister lived in Moseley and I was actually road raged by a man in a dirty old Transit van on a part of that road because I was forced to take the bumps very slowly as my car at the time was a very low slung Fiat Coupe. He gave me a very hard time and then performed an outrageous overtake. WMP did not wanna know.

White van man behaving like white van man. Move along, nothing to see here.

[Chris Bertram]

I'd also like to see some definitive evidence that installing humps reduces casualties. Most of the time when there's any follow-up coverage in the press after installation, the council spokespeople trumpet that it's been a great success because average speeds have dropped from x to y. That is not "success"; that is failure, pure and simple, without any evidence of improved accident statistics, and it tends to reveal a frequently encountered attitude that speed in itself is bad. No, it isn't. If people can get to work faster, if goods can be delivered faster, we all benefit from the economic improvements of that. We control speed on the roads not because we want people to go more slowly as an end in itself, but because higher speeds are generally associated with more and worse collisions. But if any given reduction in average speed doesn't actually lead to an improvement in casualty rates, then it is worse than worthless. But we never know one way or the other.

When Portsmouth became the first large UK city to impose blanket 20mph limits on all roads bar a few through routes, I think it turned out that accident and casualty rates went *up*. But that was all right, because people were crashing more slowly, and average speeds had indeed come down by about 2mph.

[Chris Bertram]

Speed humps (IMO) have had their day and do you know why?

SUVs.

The crims nick an X5/Range Rover/ Land Cruiser etc and they are unstoppable, they can bounce over most of them without even noticing. The yummy mummy brigade are at it too with their PCP'd Evoques generally bought by the baby daddys....

I've said this before - school run mummies and their SUVs are unaffected by humps. If councils insist on replicating the off-road experience on city streets, then drivers will react accordingly and buy off-road suitable vehicles.

[FosseWay]

I'd also like to see some definitive evidence that installing humps reduces casualties. Most of the time when there's any follow-up coverage in the press after installation, the council spokespeople trumpet that it's been a great success because average speeds have dropped from x to y. That is not "success"; that is failure, pure and simple, without any evidence of improved accident statistics, and it tends to reveal a frequently encountered attitude that speed in itself is bad. No, it isn't. If people can get to work faster, if goods can be delivered faster, we all benefit from the economic improvements of that. We control speed on the roads not because we want people to go more slowly as an end in itself, but because higher speeds are generally associated with more and worse collisions. But if any given reduction in average speed doesn't actually lead to an improvement in casualty rates, then it is worse than worthless. But we never know one way or the other.

When Portsmouth became the first large UK city to impose blanket 20mph limits on all roads bar a few through routes, I think it turned out that accident and casualty rates went *up*. But that was all right, because people were crashing more slowly, and average speeds had indeed come down by about 2mph.

Again, I'm wary of blanket statistics like that. Much as I'm generally negative towards blanket 20 mph zones, it *may* be acceptable for there to be more but less serious accidents than fewer, more serious ones. It depends on how many more and how much more serious. Equally, the reduction in speed limit and the increase in accidents may not be cause and effect, or if they are, there may be other factors involved as well that do not necessarily mean that the speed limit reduction was a bad idea. It may be, for example, that people unused to the new humps were unobservant and had a period of greater than usual tendency to rear-end the person in front at a hump. That kind of problem may well wear off as people get used to the humps.

But this kind of level of questioning of traffic calming schemes never seems to reach the public. I don't know whether that's because the schemes aren't questioned in this detail, with LAs preferring simply to follow the "slower is better" mantra, or whether the results of the questioning come too long after the introduction of the scheme for journalists to be interested in following them up, so they never get any publicity. But if the latter were the case, you'd expect at least for the council to use the successful figures from earlier implementations to be used in justifying proposed ones, and in the cases I've followed in detail that doesn't seem to have happened. (Health warning on that: the sample size is small and all cases are from before I left the UK in 2011.)

[Chris Bertram]

Actually, the Portsmouth "experiment" was for 20 limits largely without humps. It was never likely to be declared a failure, despite its aim on announcement being better road safety. More accidents, at any speed, does not, IMHO, constitute an improvement in road safety. But the criteria for success of these schemes are notoriously loosely defined. It seems that it is only necessary for road speeds to drop by a couple of mph for "success" to be trumpeted, the actual casualty figures being pretty much immaterial.

Birmingham is now rolling out extended 20 limits, with roads being covered that are instinctively *not* suitable for these limits. This is the council, of course, that conducted a survey that came out against these limits. OK, it was a council website survey, so the respondents may have been self-selecting. But if you are going to ignore the results of the survey, why conduct it in the first place? I see little chance of these new 20 limits having any effect at all. If you follow a police car through them, they will not slow to 20 or anything like in the absence of a good reason (and the speed limit itself is clearly not such a reason). They are not quite on the record as saying that they're basically uninterested in enforcing them as such - this will be concentrated on known accident hotspots, whatever the speed limit, and "voluntary compliance" will be hoped for elsewhere (code for "we're not doing anything about it"). I don't think they were seriously consulted about the limits, or if they were, they were ignored. So, a lot of money spent on 20 signs and some paint on the road for nothing. And a lot of drivers will become accustomed to exceeding the speed limit and "getting away with it", an attitude that may unfortunately inform their attitude to speed limits where they *are* appropriate. Bullet, meet foot.

[AndyB]

The other problem which comes up again and again is that long before road humps and other traffic calming became popular, drivers had lost the ability to choose a speed suitable for the conditions.

If drivers could choose a suitable speed, we would be in Martin Cassini’s fantasy land of abolishing most speed limits, traffic lights and priority junctions - but we are where we are, and that is suffering because drivers have been either too thick or selfish (or both) to choose appropriate speeds without, essentially, being told what one might be - and this has been true for decades.

[Chris Bertram]

The other problem which comes up again and again is that long before road humps and other traffic calming became popular, drivers had lost the ability to choose a speed suitable for the conditions.

According to whom? RoadPeace? Brake? SSI? This is purely a statement of opinion, and if there is statistical backing for it I'd be interested to see it. Accident and casualty rates had been falling for quite a long time before humps began their relentless march across the country.

[FosseWay]

The other problem which comes up again and again is that long before road humps and other traffic calming became popular, drivers had lost the ability to choose a speed suitable for the conditions.

I don't dispute that there exists a subset of drivers who are incapable of choosing a suitable speed for the conditions. But:

1. When speed limits are reduced, we never get a clear indication of whether the (perceived) problem before was due to people grossly exceeding the existing speed limit, or whether it was due to people going irresponsibly fast for the conditions but within the posted limit. If the latter happens a lot, that is pretty good evidence that the limit is too high. If the former is the problem, target the offending drivers, not everyone else.

2. Choosing a speed suitable for the conditions depends on dynamic conditions (weather, daylight, amount of other traffic including NMUs) as well as the physical characteristics of the road that are broadly unchanging. Setting limits and/or installing traffic calming that physically imposes a practical maximum speed can address any mismatch between drivers' perception and the latter kind of conditions (bends, hidden entrances, other fixed hazards) but it does nothing to help drivers learn to cope with the dynamic kind.

3. Micromanagement of speed tends to lead to people seeing the limit as a "this is the safe speed come what may" speed - i.e. a target, and physical impediments like humps will tend to make people think that whatever speed they feel physically comfortable driving over them at is by definition reasonable (which may as I said before involve sharp acceleration to well above anyone's reasonable idea of a limit between the humps). You mention people's inability to judge - I would argue that many of the speed reductions we see today exacerbate that problem.

Perhaps more controversially, I see a tendency to allow the balance between responsibilities of different kinds of road user becoming skewed. This is very noticeable in Sweden, where the roads authority has had a bee in its bonnet about speeding for years (while enacting legislation outlawing texting and using handheld mobiles at the wheel only last year). I regularly see a complete absence of responsible behaviour on the part of pedestrians; they will often randomly walk out into the road (and even more into the cycle path) without looking and presume that drivers are going slowly enough to stop and are being observant. This is the result of generations of road users of all kinds being told that responsibility for road safety lies solely with the drivers of motorised vehicles.

Providing a driver is driving sufficiently slowly to be able to keep his vehicle in his lane and to stop in the distance he can see to be clear, it should not in theory matter to a pedestrian what speed the driver is doing, because the pedestrian should be on the pavement except at designated crossing points. Obviously this is a gross simplification, because we all know that pedestrians don't always behave predictably and that class of road user in particular includes e.g. children, disabled people, dogs and so on. Drivers and cyclists clearly have a responsibility to take account of the different kinds of pedestrian and that not all of them will behave predictably or according to the Highway Code. But the current tendency goes too far the other way: it absolves pedestrians, and to some extent cyclists, of any responsibility to behave sensibly on the roads at all, with the result that more and more of them behave unpredictably leading to a consequent "need" to reduce road speeds the whole time.

When speed reduction schemes are mooted, I would therefore like to see statistics covering the following:

- How many vehicles exceed the existing limit.
- How many accidents occur where speed over the existing limit is a principal factor.
- How many accidents occur where inappropriate speed within the limit is a principal factor.
- How many accidents occur because a road user is in the wrong place (car on pavement or wrong side of road, pedestrian in road where there is no crossing etc.).

I then expect to see follow-up statistics after the introduction of the measure, and a direct duty on the authority to revert the changes if there is no statistical improvement.

As to the improvement in road safety statistics - again, because of the apparent lack of information of the type listed above, it is rather difficult to say what the cause of this improvement is. Off the top of my head I can come up with several probable major contributing factors that have little to do with speed:

- Better vehicle design.
- Better road design.
- Introduction and enforcement of drink-driving legislation.
- Ditto seat belts.
- Replacement of high-volume S2/S3 routes by DCs.
- Building of bypasses to take traffic that is just passing through away from residential/commercial areas.
- Reduction in journeys made on foot or bicycle (not that that is a good thing, only that it is probably a contributing factor).

[AndyB]

According to the complaints on this site about Numpties and personal experience.

Yes, it’s opinion. But when you look at it objectively, what is the most common cause of accidents? Inattention to what is going on around them, and failure to drive at a speed appropriate to the conditions - where an appropriate speed (sometimes nil in the case of those emerging from junctions dangerously, sometimes the posted limit rather than 10mph slower) would have avoided the collision altogether.

Speed limits and traffic calming do mitigate against these. I don’t mean the pointless 50s, I mean the real 50s where a minor slowing down helps traffic at junctions.

Throw in the reality that changes to vehicle design - not just ABS - have mitigated the likelihood of collision as well as the impact of collision, and a large part of the fall in collisions being related to more micromanaged road engineering.

Micromanagement shouldn’t be necessary, but with current driving standards, despite years of making driving tests more difficult and actually a test of the ability to drive, good drivers suffer.

The other problem which comes up again and again is that long before road humps and other traffic calming became popular, drivers had lost the ability to choose a speed suitable for the conditions.

According to whom? RoadPeace? Brake? SSI? This is purely a statement of opinion, and if there is statistical backing for it I'd be interested to see it. Accident and casualty rates had been falling for quite a long time before humps began their relentless march across the country.

[Bryn666]

Standalone speed humps are an awful tool really, and a symptom of the worst excesses of 90s traffic calming ideas that have mostly now been abandoned.

* They are terrible for cyclists; so fail to discourage motor traffic. My stepson ended up in hospital with internal injuries after hitting one on his bike and being thrown from it.
* Bus routes divert away from them, unless they're cushions. Which don't actually slow anyone down in my experience.
* They are maintenance liabilities, potholes form on them and in turn they collect surface water which is dangerous in winter.
* They cause vibrations and potential structural damage to adjacent properties if constructed badly.

I much prefer filtered permeability and guest streets as concepts to prevent 'rat-running'.

[Chris Bertram]

Standalone speed humps are an awful tool really, and a symptom of the worst excesses of 90s traffic calming ideas that have mostly now been abandoned.

In that case it's a shame that they're not being removed with any great haste.

[Bryn666]

Standalone speed humps are an awful tool really, and a symptom of the worst excesses of 90s traffic calming ideas that have mostly now been abandoned.

In that case it's a shame that they're not being removed with any great haste.

Abandoned as in "not doing more of it" rather than actively removing.

That said I have successfully removed speed humps from a road where they were unpopular and caused bus users to be very uncomfortable. See here: https://goo.gl/maps/6zWCpRvhjvy (2009) and https://goo.gl/maps/i4FnMazARR92 (2017).