Fun With Moderate & Controlled Variations In Vertical Carriageway Alignments (aka I've Got The Hump)

Speed humps, sleeping policemen, biscuits, cushions, tables, side entries, raised crossings, thumps: all names I have heard used to describe the humble road hump.

I have a bit of a love-hate relationship with Road Humps (to use the proper and legally defined term) because if used properly, they will get traffic speeds down. They can also be used to provide level pedestrian crossing routes and priority cycle tracks. The problem with them is that they can cause noise and vibration to those living near them, they are often uncomfortable to cycle over and they are another thing to maintain out on the street.

This dropped kerb is still on a hump, but a kerb upstand has been
left for blind and partially-sighted people to be able to find the edge
of the footway. If the whole footway is flush with a hump, then we
have the potential issue of trying to put tactile paving in everywhere
which can be a mess and doesn't work round corners unless we are
aiming to guide people into the middle of the road!

The Basics
Highway authorities are enabled to build road humps by virtue of Section 90A of the Highways Act 1980 (as amended). There are several other sections (down to 90F) which set out the particulars - have a read yourself as it is a bit too boring to explain here in full, but there are definitions, the requirements for consultation and special cases in London (where something not defined elsewhere is proposed). 

Humps are technically road obstructions and so have been specifically allowed within the law (so long as they are built within the parameters of the regulations).

Section 90D essentially gives the Secretary of State the power to make Regulations controlling the use of road humps and this has spawned the Highways (Road Humps) Regulations - we are currently on the 1999 version. These Regulations deal with a variety of matters;

• Consultation,
• Dimensions, nature of humps and location of humps,
• Lighting,
• Traffic signs,
• Relaxations within 20mph Zones (generally signage and lighting)

Consultation must include the police, an advert in the local press and site notices (S90C HA1980) and could include a local inquiry. In addition, the fire brigade, ambulance service and

"organisations appearing ... to represent persons who use the highway to which the proposal related, or to represent persons who are otherwise likely to be affected by the road hump". (S3 HRHR1999).

These other persons could include residents and businesses, cycling groups, local conservation groups and so on - although it is up to the highway authority who is consulted (it is usual to maintain a standard list which includes all of the groups required for various pieces of law to make life easier).

For dimensions/ nature, we have a lot of flexibility. They must be built at right angles to an imaginary centre line of the carriageway, be at least 900mm long (so no rubber retail park humps!), at least 25mm high, be no more than 100mm high and have no vertical face more than 6mm high. There is no actually regulation on the shape of humps or ramp gradients, but I will cover some of that later.  We are also allowed to put zebra and signalised pedestrian crossings on top of humps (subject to a little more regulation). Additionally, they should not be used close to (or in!) tunnels, bridges, level crossings and tram tracks. 

Your basic, bog standard round top road hump.

Types Of Hump

The regulations allow a great deal of variety, but there are three common types of hump in use; round top humps, flat-top humps (sometimes called speed tables) and cushions. Round top humps have a circular profile and are normally 3.7 metres long (in the direction of travel, not across the carriageway).

The 3.7m dimension is a remnant of the 1986 Regulations which prescribed the shape of the hump (which was based on prior research), but nothing stops us making them shorter (down to 900mm) or longer. A short hump for the same given height will be harder to pass over and will lead to more noise/ vibration and a longer one will be less effective. Subsequent regulations gradually relaxed what could be done.

A sinusoidal road hump lovingly crafted from 55/10 HRA which is by
far the best material to use in my opinion as it is pretty much
bullet proof!

A development of round top humps is the sinusoidal hump which has (you guessed it) a sinusoidal cross-section. It means that in the direction of travel, the hump starts quite flat and then gradually gets steep. It then curves over the top and then gradually gets less steep on the other side. 

There is more to read in Traffic Advisory Leaflets 9/98 and 10/00 (see below), but from the point of view of riding a bike, sinusoidal humps are so much more comfortable to traverse than round top and indeed flat top with steep ramps and have a similar effect on vehicle speed as round top.

Sinusoidal humps are a little bit more difficult to construct than round top humps, but a decent asphalt gang will have no problem. As with round top humps, an area around the edge of the hump will be cut out and an asphalt "core" laid in the centre. The surfacing will then be laid over the top (allowing for compaction) and rolled to the correct levels - sinusoidal humps rely on the gang spending a little more time setting things up and a bit of skill with the roller. Really, if anyone is think if putting in humps, make them sinusoidal as it will be better for cyclists.

A set of three cushions on a wide road.

Next, we have cushions. These were developed to be able to traffic calm streets which are used by buses, ambulances and fire engines (or the odd lorry). 

The idea is that these larger vehicles can straddle the cushion so the impact is not as great for cars which have narrower wheel track. 

A lot of the skill in getting them right is their position in the running lanes and dimensions - the wider the cushion, the better the speed reduction. There is a Traffic Advisory Leaflet to assist (TAL1/98 - see link below).

A closer view of some cushions.

Cushions are not something to cycle over as the ramps are often steep. One can of course cycle between them, but they force you to either hug the channel on the left hand side (often getting close to the kerb) or play chicken in the middle of the road. Wider roads will have 3 cushions (I have seen 4!) which might be a little better for cycling. 

Unless there are parking restrictions through the set of cushions, drivers (and cyclists) are often forced into clattering over them. This often leads to complaints from those living near them.

They are sometimes used in close proximity to traffic islands and pedestrian refuges which can be very effective for reducing traffic speeds, but we have the issue of creating not only a pinch point for cyclists, but giving the choice of either passing on the left next to a kerb or on the right, next to the island. Cushions remain a compromise and I am not really a fan. Of course, there does remain the fundamental issue of needing to traffic-calm a through route in the first place which is not dealing with the issue of the appropriateness of the traffic using it.

The third type of road hump is the flat top hump (or speed table). These can be stand alone as round top humps, be used within junctions (providing a handy crossing point) or within zebra/ signal-controlled pedestrian crossings. 

Flat top humps are more forgiving than round top humps, but less than sinusoidal. Of course, a sinusoidal ramp could be used and some manufacturers make precast sinusoidal ramp segments (although they are only of use on flat carriageways rather than ones with a camber).

This flat top hump (speed table) covers an entire 4-arm junction and
provides flush dropped kerbs in all directions to help all pedestrians
cross on all arms of the junction. Quite an unusual layout as it is
normal for just the side roads to get the dropped kerbs.

Flat top humps are also useful at junctions for not only helping reduce speeds (although drivers turning in and out should be reasonably expected to slow down), but to provide a more level walking surface for pedestrians (and to reinforce pedestrians already crossing having priority).

It is also possible to give cyclists absolute priority over traffic using normal give way markings to drivers. It is not often used, but means that a cycle track crossing a road becomes the "main road" at a crossroads formed with another road. This allowance is buried within the Traffic Signs Regulations & General Directions 2002 under Regulation 25(6). The language in the regulation suggests that the hump cannot be right on a junction and so would need to be set back to provide space for a give way marking to drivers on both sides of the hump.

Cycle track with priority over traffic, near a junction.
Image from Google Streetview.

This arrangement does allow drivers to turn off a main road and then stop, but as these arrangements tend to be used in quieter places, cycle traffic probably dominates occasional access by vehicles. Compare this approach with the argument that cycle tracks can have priority anyway as they can be part of the main road. This is an area which really needs tidying up because designers tend to shy away anything which seems unusual (despite being allowed for years!)

Flat top humps are more suitable for bus routes and perhaps busier roads often used by emergency vehicles. In these locations, ramp gradients of 1 in 20 or 1 in 15 might be suitable rather than the steeper 1 in 12 (seen as the maximum in line with accessibility for people using wheelchairs). The emergency services do not automatically object to humps, but they need to be engaged from the start.

There are other permutations of humps course. One might built a hump kerb to kerb with localised drainage works (so the carriageway doesn't flood!) but this can add quite a bit of cost. the hump can be stopped short of the kerb (see the sinusoidal example above). A hump stopped short of the kerb can be a hazard for cyclists (getting trapped in the gap) or pedestrians (tripping) and so as usual, sites need to be dealt with on their merits. A longitudinal road marking picking out the "useable" edge of the carriageway is useful where the hump stops short of the kerb - compare the photos above (although the sinusoidal hump scheme was still waiting for this when I took the photo).

My examples have so far been all constructed from asphalt, so here is a flat top hump constructed from block paving. 80mm thick paviours should be used to take traffic loading and a good foundation is essential. The other important point is that all edges of block paved area need good lateral restraint or they will spread under wheel load and ruts will form.

This hump has granite setts for ramps and because it was built in a 20mph Zone, the triangular hump road markings were not needed as the hump is very conspicuous. Again, care is needed when using non-asphalt materials for ramps as they take the brunt of wheel loadings and unless well-detailed, they will fail.

Current Guidance

OK, I have said before that we should be wary of "old" guidance as it might not be current. Where humps are concerned, guidance is showing its age, but much is relevant. The Traffic Advisory leaflets are a good starting place as follows;

• TAL7/96 - Highways (Road Humps) Regulations 1996 - yes out of date, but not much changed from 1996 to 1999 other than lighting requirements (because of a standards change) and a relaxation on signing and lighting in a 20mph Zone (more on that later),

• TAL1/98 - Speed Cushion Schemes - essentially the outcome of research into their use and suggested optimum dimensions for different situations,

• TAL9/98 - Sinusoidal, S & H Road Humps - a guide to some strangely shaped humps designed to slow down cars, but not affect other users (emergency services and cyclists for example). I have only ever use sinusoidal from this list and to be honest, the H and S humps seem to be a colossal pain in the backside to build and maintain

• TAL10/00 - Road Humps: Discomfort, Noise & Ground-borne Vibration - again, this document gives some research into the subject and is actually quite interesting. In terms of user discomfort, it shows that sinusoidal humps are more forgiving to cyclists. For buses and other vehicles, suspension technology has moved a lot in 14 years and so the results will be less relevant. The vibration part is interesting and shows how the soils underlying a road can have a big impact

Final Thoughts

Like any design element, road humps have their place and will no doubt still be used. They have limitations and as usual, should be used in the right place. I can think of lots of locations where humps have been used to slow traffic, where the real issue is that the traffic shouldn't be there in the first place. 

Humps can therefore be symptom of the problem and not a cure for the problem, especially if high levels of rat-running traffic still remain with the added issue of noise and vibration from the humps and the impact on pedestrians and cyclists.

*thanks to @nuttyxander for the inspiration for the title of this post ;-)

Cycling Spring

My posts over the last few weeks have been very bike-based and this week is no exception. I will remember to be a highway engineer and post something technical next week (maybe).

Today is the local and European elections. For the Euros, my decision was simple (no, I won't say here - ask me in the pub). Locally, it was a little more difficult (not a huge choice), but in the end, I went for a party who fielded 3 candidates who all signed up to the #Space4Cycling campaign at an early stage. Only time will tell if they get elected and if they carry through on their pledge.

By carry through, I mean actually challenge the current thinking locally and actually demand some decent funding and design approaches where we can do some good. My next highways committee will be interesting to say the least (and that is as much as you get about the day job here - the line is too fine!).

In casting my vote, I cycled round the corner to the polling station to stick my crosses down in person which is something I have always done - for a few seconds, I had the full power of democracy behind me. This was a contrast to last night where the power of the people was also being demonstrated.

After being a bit on the fence about attending, I rode across East London (and headed south) to the Elephant & Castle to participate in the #StopKillingCyclists "die-in" following the death of Abdelkhalak Lahyani at the junction.

I was sitting on the fence partly because of time (getting to the protest on time by bike was a challenge, but my new daily bike performed brilliantly) and partly because I am part of the industry and bureaucracy which leads to stuff being built (and I mean things which affect pedestrians too). But, I am just one engineer who is learning as he goes and as I often tell colleagues at work, you need to live the designs you work on and that must include coming to terms with how those designs turn out and who they affect.

The decision on what gets built on the highway network is largely a political one, but it is the job of those designing the schemes and advising the politicians to explain what the consequences are (good and bad) of something being put forward. However, we could and should do more as a profession in explaining how we can improve the transport in our towns and cities and increasingly how important walking and cycling will be. I for one am looking forward to voting in the General Election next year and the London Mayoral and GLA elections in 2016!

#Space4Cycling #BigRide London

bonus post this week about today's space for cycling big ride in london. 

Actually, I will let the photos do the talking this time!

The Big Ride 2014

There is just one thing to think about this week and that is the #space4cycling big ride which is taking place on saturday with several events across the country.

Rides are planned in London, Newcastle, Leeds, Manchester, Sheffield and Sollihull (sorry if there are more and I have missed them!)

The rides aim to send a loud, unified and clear message to those standing for election next week that we want #Space4Cycling and indeed the Country needs #Space4Cycling.

The London Cycling Campaign has produced resources which can be downloaded here and there is still time to contact your council candidates to demand #Space4Cycling here.

This ride and the messages behind it is not just important to me as a bike riding resident of London, it is important as those who are elected will be running the place where I work for the next 5 years and their attitudes will directly affect the work I do. 

We can either carry on as usual, failing to change our streets for people and dealing with the congestion and pollution, or we can do something new that cities all over the world have proved to work - providing #Space4Cycling.

Ranty Junior and I will be going to the London ride, probably via CS3 with a food stop at Borough Market (as usual!). Like many, we will be wearing red, the colour of the LCC and we will be ready to make some noise!

I hope to see thousands of you on Saturday!

Vote 2014: Vote #Space4Cycling

It's election time again on 22nd May with local and European votes taking place.

The local elections will give people the opportunity to vote for those candidates they feel best represent their interests and not surprisingly, I am going to vote for cycling (although the candidates in my area don't seem to be taking much interest sadly).

For those of us in London, all council seats in the 32 boroughs are up for grabs. Elsewhere there are various elections in the metropolitan boroughs, unitary authorities, district councils and others.

In London, the London Cycling Campaign (LCC) has been running its #Space4Cycling campaign for a while now with a website designed to help you contact candidates in your area to tell them what is being asked for at ward level following a huge amount of work by local LCC groups. The campaign has also gone countrywide with help from CTC.

So, what does the campaign call for? Well, here are the headlines;

Protected space on main roads

This means fully protected space on those busy and fast main roads. LCC's policy is that any street with more than 2000 Passenger Car Units per day is the cut off point.

We are not talking about painting a white line down the middle of an already cluttered footway, we don't want to make conditions worse for pedestrians. Protected space means a proper job that everyone can use. It means proper investment in serious civil engineering to deal with pinch points at bridges and big junctions.

Removing through motor traffic in residential areas

Our residential streets are all to often the bypasses to the busy main roads which makes them horrible to cycle on and very intimidating for pedestrians too.

Through fairly simple pieces of highway engineering, we can rework these streets to prevent rat running by people with no real need to be there. Children no longer play in the streets, neighbours don't spend time talking to each other - changing these streets is not just about cycling.

There are challenges for sure. Parking and servicing will be problems in some places, but my view is most of these problems can be overcome. We are able to use experimental Traffic Regulation Orders to cheaply try layouts. If there are problems, we can change things. With rat-running, comes speed.

Lower speed limits

20mph should be the default speed limit where people live and indeed work, walk, cycle and play. On those streets where through traffic has been removed, 20mph can help drivers realise that they are the visitors. Many other European countries have a lower speeds which work, why can't we do the same? If we need to go back up to a higher speed limit, then it should be with protected space.

Cycle-friendly town centres

People on bikes spend money. Pedestrians spend money. Retailers don't always see this. Indeed, studies are showing that people walking and cycling spend more in town centres than those arriving by car do.

We are not talking about the out-of-town or edge-of-town retail centres, we are talking about our town centres. These are the town centres which politicians always go on about and where many think cheap parking is the answer. This is yesterday's news. Town centres need to adapt and cycling is helping many to do just that.

Safe routes to school

School Travel Plans, training and encouragement will only get you so far, but if your route to school is on a busy or fast road; if your route is full of parents parking everywhere (like in the photo); if your route crosses big roads; you are not going to be allowed to cycle to school. Travel habits stay with people through their lives. Kids want to ride their bikes. Adults with their cars stop them riding their bikes, whether driving them to school or making the roads feel to unsafe to cycle on.

Routes through green spaces

No traffic, no pollution, no noise. Cycling through parks, open spaces and greenways is wonderful and feels safe.

But, routes need to be direct, open 24 hours a day (many parks close at night) and lit so they can still be used in the evenings, especially in winter.

These open spaces can often create very short direct links, but other users need to be won over as again, pedestrians, dog walkers and people with young children may not want to mix with those on the head-down commute. As usual, it is all about designing for the context and not settling for a second-rate scheme.

I have used the LCC's tool to contact the candidates in my ward to ask if they will support #Space4Cycling, I hope you can too - it only takes a couple of minutes.

There are also loads of resources to help with local campaigns - it might even be a personal campaign where you put a poster in your window to remind door-stepping candidates what matters to you.

For those of you in London or who can get to London, keep Saturday 17th May free as the LCC has organised its #Space4Cycling Big Ride. 

The ride will be on marshaled, traffic-free streets and as well as being a fun event for the family, it will be sending a message to the politicians that people want to cycle in safety.

Your vote is important to those wishing to get elected and so if you get a chance, let them know that there are an awful lot of voters out there who either ride bikes or would like to ride and we demand #Space4Cycling! See you in the saddle!

Filling The Vacuum

The uk government has consistently failed to keep up with thinking in designing for walking and cycling, and people are rightly frustrated.

Most of the problem is down to the lack of political interest and enthusiasm for any solution beyond the end of a car bonnet. For years, the only "official" road design manual was the "Design Manual for Roads & Bridges" which was and still is only relevant for trunk roads and motorways; essentially the roads operated by the Highways Agency for England and similar roads under the control of the Scottish, Welsh and Northern Ireland administrations (who are increasingly going it alone anyway).

Walking and cycling are marginalised. Although there is some advice in the DMRB when it comes to non-car modes, it is rarely followed even on Highways Agency roads. Other than the technical structural guidance on bridge works, it has no application to local streets.

In 2007, "Manual for Streets" was published which raised the game for the design of residential streets. It was a government document, but it was put together by the industry with representation from local authorities, consultants, developers and others. On the whole I like it and the section on walking is quite detailed. The section on providing for cycling is short and pretty poor; things have moved on and this "official" guidance hasn't.

7 years after MfS, those campaigning for walking and cycling or for just better streets haven't got anything "official" to refer to. For those of use on the design side and in local authorities, our life is not helped by the lack of guidance. If there was up to date guidance on developing walking and cycling networks, things can be measured against it and facilities can be made consistent. I have covered some if this before.

What has happened is people have gone at it themselves and with varying results. In 2010, the Chartered Institution of Highways & Transportation released Manual for Streets 2. Although it was "sort of" endorsed by government, it remains an industry document and it comes at streets more from a policy and planning point of view than the detail needed to actually design and build stuff.

This week, two more "unofficial" design guides came out. First, we have Sustrans with its "Handbook for Cycle-Friendly Design" was has had a savaging on Twitter and in the blogosphere. To be fair to Sustrans, they do suggest that it is the start of a process and in my opinion, there is some good stuff in there. The early parts of the document is about user needs and on the whole, it is pretty sound, but it falls down massively with a couple of statements;

Target user: design should be attractive and comfortable for the less confident cyclist – a sensible 12 year old or novice adult who is trained to National Standards / Bikeability Level 2 – but should aim to provide for the more confident cyclist as well. Where more confident cyclists choose not to use any facilities provided their needs should also be addressed with separate provision where appropriate; they should not be compromised by the design;

Design in line with cycle training: on-highway design should reinforce how people are taught to cycle in National Standards / Bikeability Level 2, in particular primary and secondary road positioning;

My personal message to Sustrans is that I am a confident cyclist, in the saddle most days and mixing with traffic much of the time. I have never been "trained", but I have ridden "primary" in a lot of places, including the old bit of Cycle Superhighway 2 in London. Do you know what? I prefer the protected bit of the Stratford extension!

I thought we were now moving towards designing for most people rather than the two-tier approach which does rather come through elsewhere in the document and sadly the good is soon forgotten and people remember the bad. Sustrans does intend to revisit this and it is a starting point, but they should (in my opinion) have come out in unqualified support to provide proper space where required (and that goes for pedestrians). Had they done so, the "target user" and "design in line with cycle training" would have merely been statements of the current position which we need to move on from.

The other release was "Making Space for Cycling" which has been put together by the Cambridge Cycling Campaign (CCC) and published by Cyclenation. The web-based format is excellent and means it can be easily updated (also available as a pdf). I think the guide is pretty damn awesome and it shows more of what we should be aspiring to. 

It seems to be aimed more a new build and the non-techn, but much of it can be retrofitted to existing streets. My one criticism is that it is extremely light on practical design layouts which at least Sustrans has tried to deal with (not always well). Perhaps it is more of a marketing document aimed at those who don't know what people want and that is no bad thing.

It is very easy to sit back in one's chair and criticise and many people do. It is a lot harder to be constructive and offer help and advice. We should remember that both Sustrans and CCC are trying to move things on (in their own ways) and this is a symptom of a continued lack of leadership from the Government. Sustrans, CCC and indeed all of us commenting on design would be making much better use of our time responding to proposed National design standards which everyone can sign up to.

National standards (and please don't forget pedestrians here) would ensure that things are done consistently (and I mean that from an assessment as well as a design point of view). It would be a huge help to local authorities as many of their highways people don't cycle and so don't understand the user experience. We are not going to be in a position any time soon where all highway engineers cycle and until then, they need to be able to understand how it all hangs together.

Of course, the larger authorities are going it along. In London, we were promised the radically overhauled London Cycling Design Standards back in December. Then March. It is now May. The previous LCDS were published in 2005 and are of course massively out of date. I think I know why the new edition is being delayed which I will come back to in a bit. Wales has passed its "Active Travel Act" which will undoubtedly lead to design guidance.

This might be the way forward where the devolved and regional governments produce their own guidance and the National Government simply puts the legislation in place to facilitate. I do worry that we will end up with area-specific layouts which lack consistency, but only time will tell.

Back to the reason for the LCDS being delayed. This week the Government published a consultation on a huge rewrite of the Traffic Signs Regulations and General Directions (TSRGD). Pencilled in as TSRGD2015, this will be the background legal framework to what gets installed on the streets in the next few years. I think TfL has waited for several reasons (which I might be wrong with of course!);

• There is a lot of new cycling-specific stuff in there which TfL has been trialling and lobbying for, such as low level cycle signals and cycle zebra crossings. Publication of the draft TSRGD2015 will give TfL confidence that the new LCDS will have layouts which can be lawfully used. (perhaps a liability and reputational concern about an authority going it alone!)

• Politically, had TfL gone for it before the TSRGD was updated, it would essentially have been Boris getting one over the Government which may not have gone down well.

• They raised expections to such a high level, there has been the need for a lot of rewriting (possibly by Andrew Gilligan!) to get the guidance to the standard everyone is now rightly demanding in London.

These regulations matter because they link back to road traffic law and this is important in how things work for safety, how things get enforced and of course makes sure that things are consistently laid out UK-wide. Believe me that I have only been through the draft a couple of times so far, but TSRGD15 will finally unshackle design creativity and set us well on the way to getting things right for walking and cycling.

The Coalition has made big noises about localism and perhaps leaving authorities to come up with local guidance is par for the course with them. TSRGD15 will give the enabling framework on what can be done, it is up to local authorities to use it. Only time will tell if this approach will work and if the vacuum will be properly filled.

My final point is that I urge anyone with a passing interest to read the TSRGD15 consultation and respond, even it is just to say you think it is all great as it will show the government that people are watching. I know that many organisations will be responding and I will probably do as well as a practitioner - I might even post my more detailed views in due course.