Sunday, 19 January 2020

Terrible Barrier

Yesterday, I combined an invitation to be a panelist at Camcycle's AGM with a bit of a mooch around Cambridge city centre and a mini infrastructure safari.

I'm hoping to be back for a proper infrastructure safari later this year and so this week, I'm going to concentrate on one thing and that's the new counter terrorism installation at Kings Parade in the historic heart of Cambridge.

It's a location which has been a concern from a counter terrorism point of view for some time. We've seen the incidents where vehicles have been driven into crowds of people and Kings Parade is a popular tourist spot for tourists taking photos of Kings College as well as enjoying the beauty of the street.

The problem is, Kings Parade is also one of the busiest streets in the city for cycle traffic and so one would have thought that this would be taken into account in designing the installation. Sadly, it seems that cycling and walking have been ignored.

The barrier has been installed here and is a familiar collection of oval (on plan) concrete-filled shell blocks (called "barges" by the manufacturer) combined with a central openable gate. The barges weight about 3 tonnes each. The installation is designed to stop someone driving a vehicle into a crowd - know as "hostile vehicle mitigation" (HVM). 

The system uses its mass and friction with the ground to prevent someone driving a vehicle through, although the units will be moved in the event of a high speed collision - the point is to dissipate energy and bring a vehicle to a halt, probably with extreme damage. The photo above shows a pair of barges either side of the gate (for occasional access I assume). The barges are connected and so there's a lot of mass there. There are two individually placed barges on each side of the gate assembly which are offset from each other but not connected. 

The street has a wide footway on the eastern side of the street and a narrower one on the west side; a fairly narrow carriageway and a loading bay (the cobbled are to the left of the carriageway in the photograph). The installation of the gate straddles the carriageway and the loading bay (which turns into a hard strip) with an area left for cycle traffic to the western side of the carriageway. The footway width on each side is maintained, albeit with two barges each.

The photograph above shows a closer view of the cycle side of the installation which has a pretty narrow gap between the barges - so narrow in fact that people have to cycle through in single file. That wouldn't be so bad, except it's a gap for two-way cycle traffic!

On close up, it's even worse. Almost half the space is a granite sett channel (with a slot drain in centre) and a kerb with a slight upstand. Granite can be very slippery to cycle over and the design means that every person who cycles through in damp or frosty conditions is at risk of falling off their cycle - right into the barges. While I was on site, I saw a few people cycling and one motorcyclist across the footway.

Two-way cycling is not possible and so people have to give way to each other. Although people cycling are very adept at adjusting their speed and direction, this pinch point slows progress and creates the potential for head on collisions - here's me cycling through;

I had a look at about 10.30 on a Saturday morning - imagine the chaos on a weekday peak - it really is so poorly thought out.

Just beyond the barrier to the south, there is a junction where Kings Parade turns into Trumpington Street with Bene't Street off to the east. Trumpington Street has motor traffic restrictions (signs) from the south from it's junction with Silver Street, but of course any would-be terrorist isn't bothered about traffic signs. In theory, therefore, someone could drive about 160m along Trumpington Street where there are plenty of people milling about.

The area to the north of the barrier is better protected. Kings Parade becomes Senate House Hill where there is a rising bollard which appears to be used to permit emergency access; there's probably more people milling around to the north of the barrier. 

The wider problem the city centre has from a counter terrorism point of view is that although there's a large pedestrian (and cycling) zone, there is an "except access" exemption and frankly anywhere could be a target. There will be analysis to demonstrate that Kings Parade is a site of concern, but it seems to me that a larger review is needed. As far as the current barriers go, they really need to be changed.

It's a wider issue for the UK. We keep rolling out this stuff in response to concerns about terrorism, but in the process we make day-to-day access for walking and cycling more awkward as well as helping to clutter our streets. In many ways, the terrorists have already won.

Saturday, 11 January 2020

So Near, So Far

I happened to be in Cambridge this week and I also happened to see some relatively new streets. You would think that in the UK city with the highest rate of cycling that I'd have seen some world class cycling infrastructure? Sadly not.

OK, what I did see in the Eddington development, in the northwest of the city was far better than literally most of the UK, there were some fundamental flaws with what had been built. I think most of the issues lie with the design rather than a lack of skills from the road workers who built it.

I don't know a lot about the development itself, but from what I have read, it aims to be a highly sustainable development and it certainly looks impressive, but as this is a highways and transport blog, it's the road details which interest me. 

The development sits between Madingley Road and Huntingdon Road with a new spine road connecting the two - Eddington Avenue. Towards the centre of the site, Eddington Avenue has a a bus gate which operates between 7am and 7pm. The bus gate is meant to be controlled by rising bollards, but it is currently staffed because of mechanical problems (the street network being currently under private developer control).

The bus gate is bypassed with Turing Way which immediately creates a potential issue of attracting through traffic. This may or may not prove to be an issue in the future as I don't know how attractive the route will be and in principle, a distributor road isn't necessarily an issue. In fact, the road layout largely provides protected and buffered space for walking and cycling.

As can be seen in the photograph above (at the north end of Eddington Avenue) there is a footway, a (one-way) cycle track and a verge buffer on each side of the street. Bus stops are floating and every so often there are communal underground refuse collection areas with laybys for refuse vehicles. Actually, it has a very Dutch feel to it. The cycle tracks are machine laid in red asphalt and the footways are finished in attract concrete block paving.

However, the disappointment for me is three-fold. First the central part of Eddington Avenue loses the cycle tracks and one is expected to mix with general traffic - the designers were trying to create a town square, but in transport terms it doesn't work for me. Despite the bus gate, there is quite a bit of on-street parking near a new primary school and some of the parking is echelon laid out to encourage drivers to reverse out which is a safety risk for cycling. 

There are connections through the The Ridge Way cycle route which are not defined through the town square which means people cycling have to pick their way through people walking and street furniture so it's less successful for walking too. I don't know who decided on the town square idea, but for it to have worked well, the connections to The Ridgeway should have been acknowledged, embraced and made legible for people walking and cycling. The area should have been car-free, and if not, the cycle tracks should have been carried through. Despite being an access to the primary school, parents really won't want to mix with traffic and buses.

Second, the provision for walking and cycling at each end of the development where it connects to the existing road network is poor. The signalised junction with Huntingdon Road doesn't even have a pedestrian crossing over Huntingdon Road and people cycling are mixing with traffic within the junction, although the paint gives way to protected cycle tracks along Eddington Avenue. There is a toucan crossing over the entrance to Eddington Avenue, but it is two-stage and staggered, the latter being less helpful to the users of non-standard and adapted cycles;

The photograph above shows how people cycling north towards Huntingdon Road are treated - they are essentially dropped into a central advisory cycle lane which ends at an advanced stop line. Also known as a "murderstrip" by the Belgians. It is not a layout which is safe for all and so people jump onto the footways and in fact, there are blue shared-use signs after one is dumped in the road, expect there's no way onto the footway from the road. At the Madingley Road end, it's a little better with toucans crossings all round, but again, we have two-stage staggered arrangements.

The layout of the two connections will have been heavily influenced by Cambridgeshire County Council which has prioritised motor traffic capacity over active travel. Huntingdon Road and Madingley Road are both A-roads providing connections into Cambridge City Centre. Despite the Madingley Road end of Eddington Avenue serving a large park which should take out traffic going into the city, the decision has been taken to maintain traffic capacity.

I can't lay this totally at the County, they are responding to how the UK transport planning is arranged. If a development creates traffic congestion, then there are grounds to refuse planning consent. Therefore, everyone involved works hard to ensure a scheme is (as far as possible) motor traffic neutral and walking and cycling usually suffers. This can be traced back through planning and transport legislation which makes it hard for a planning authority and its councillors form acting differently. 

What we should be doing is setting objectives which prioritise walking, cycling and public transport and giving what's left to the private car. In this location, this would have meant single-stage crossings with walking and cycling have their own separate and protected space.

My third disappointment is the detailing on Eddington Avenue and Turing Way. This is a new build and it should have been world class, but it doesn't even conform to designs which we managed to build several years ago.

The photograph above captures the issues. The footway and cycle track are at the same level and so the practice has been to provide tactile paving and a raised demarcation kerb between the two. On the walking side, the tactile paving has ridges running across the line of travel (known as ladder paving) and on the cycle side, the tactile paving has ridges running along the line of travel (tram paving). This arrangement is to help visually impaired people find the right side to walk.

The paving is present, but it is inconsistently applied and the central demarcation block is missing - a basic edging kerb has been used. The lack of raised demarcation makes it harder for visually impaired people to know where the edge of the footway is. Had it been provided, it would have looked like this;

Had the cycle tracks been stepped (i.e. at a lower level than the footway) then we could have dispensed with pretty much all of the tram and ladder paving and given better information to visually impaired people such as this example which shows a higher kerb where people might walk towards the cycle track perpendicularly and a lower (and forgiving kerb) along the line of travel. Given the scale of the site, the developer could have had 30° splay kerbs developed!

The other problem comes at junctions and accesses. The modern principle is to make footways and cycle tracks continuous over low traffic junctions and accesses to prioritise walking and cycling. The photograph below is a service access to the primary school which I am assuming is very seldom used.

We have tram and ladder paving to ensure visually impaired people are on the correct side and the footway ends with blister paving to show a crossing point. Kerbs from the edge of the carriageway continue into the access along with double yellow lines - cues to the driver that they have priority. The immediate junction with the main road also looks like, well a junction. People walking and cycling see "their" paving carried through the access which gives an impression that they might have priority. The problem here is, that in the event that everyone thinks they have priority, then it's those walking and cycling who come off worse.

At a seldom used access, this is probably not a significant safety risk, but at the junction of Eddington Avenue and Turing Way is most definitely is;

The paving colour is taken through the junction again, although now we have blister paving on the footway and cycle track. For cycling, the movement is one-way into the distance and so there is a risk of being hit from a driver turning left. The cycle track is not set very far into the side road (Eddington Avenue) and so someone cycling would have to check over their right shoulder that it's safe to cross. The dropped kerbs are not flush either (although that is a construction issue). 

There are a number of crossing points over the spine road (which is a good thing). The photograph above is typical with a tactile deluge. The correct detail here would be to keep the cycle track and the footway running through with a localised crossing of the cycle track to the "floating" waiting area to cross the main road. 

The other frustration is for people wanting to cross the road by cycle. The photograph above has a side road coming from the right. If one was cycling and wanted to turn right, one would expect access to the cycle track on the left hand side of the photograph. But one cannot because there is no gap in the verge. Conversely one cannot turn right from the cycle track into the side street opposite.

There are some great details. The verges are actually part of the surface water management system, give space for trees and create a safety buffer. There are on-street parking bays which have a buffer from the cycle track to stop dooring incidents. Where space is a little more constrained, the cycle tracks are next to the carriageway, but a wide kerb has been used to help provide a buffer and a visual break. The town square looks rather Scandinavian (if you ignore the parking and lack of clear cycling space).

It's now probably too late to go back and retrofit the site to my exacting idea of utopia. Demarcation blocks are 200mm wide and the work to remove the edging kerbs and their foundations to put in demarcation blocks would be substantial. Reworking the quiet junctions and access should be easier (but still costly), but now we have entrance kerbs in the UK, we could do something like this;

Where the side streets meet the main road, we could add cycling access to the cycle track opposite and tidy up the pedestrian crossing points like this;

The greatest challenge will be to sort out the junction of Eddington Avenue and Turing Way (remembering there are two junctions). I would like to see the crossing points set back into Eddington Avenue at least 5 or 6 metres and a design taken on priority. Because buses are turning into the side street, the entrance kerb treatment would work because bus traffic will damage the kerbs and paving.

I would like to set the crossings point back into the side street about 5 or 6 metres. Then a decision is needed in terms of priority. The layout should either make it clear that traffic has priority like this;

Or we can continue the walking and cycling priority with a parallel zebra crossing like this;

If the crossing point cannot be set back, it is harder to decide, but given it's Cambridge where cycling is being gradually improved I would look at the parallel crossing option and seeing if the junction could be made any tighter for turning traffic. Luckily, it's not my decision and I'm not advising!

So there we have it, a good try to be sure. But, the scheme is let down by the lack of attention to detail which is a shame because as is often the case, doing things correctly doesn't cost any more than doing them badly.

Saturday, 4 January 2020

Out Of Alignment

I think I have got a pretty good handle on the rules, regulations, guidance and practices of how street elements fit together, so even if I don't realise it at first, things gnaw away at the back of my mind.

Zebra crossings are one such element which I notice things wrong with all too often, but how about this example I found near Kings Cross Station in Central London;

It's actually part of a set of three zebra crossings which all land on a triangular pedestrian refuge island within a wider gyratory - here's a better view from Google with the crossing in the photograph above being the one on the left hand side of the view below;

There's quite a lot "wrong" with the layout such as grey tactile paving being used when red is the standard colour for "controlled" crossings (signals and zebras), the tactile paving not properly lining up across the crossings and poor lighting of the crossing points as well as poor local drainage and maintenance issues.

The use of zebras within a layout such as this does at least accommodate pedestrian desire lines and so I've no in principle objection, although being a gyratory there is certainly a high risk of drivers speeding off peak.

However, the thing which gnawed at me was the layout of the stripes. It was only when I used to crossing for the third time in a few weeks that I noticed it. In the UK, zebra crossing stripes are rectangular in shape and are arranged in the direction of travel. The regulations governing the layout require the stripes closest to the kerb to be black (or the carriageway colour if there's enough contrast with the white stripes).

The figure below shows what has been installed (left) and what should have been installed (right);

The rules are quite flexible in terms of the layout because every situation might need particular layout requirements, but having the stripes rectangular is a fixed required. Section 16 of Chapter 6 of the Traffic Signs Manual gives full details.

But does this mistake matter in reality? From a legislative point of view, one can argue that the crossing is not lawful and the implication is that the rule of carriageway users having to stop for a pedestrian on the crossing won't apply but how many drivers approaching this installation would think that - judging by the behaviour of some people, the requirement to stop is routinely ignored.

As ever, this kind of thing would need testing in court either as the result of a collision or through a claim or other civil procedure. On balance, I would say that if it looks like a zebra crossing then it is and a court would probably consider a bit of variation on stripe arrangement as de minimis in the same way as a failed Belisha beacon would be. However, rules are put into place for consistency and so this stuff should be right and I would extend that to zebra crossings used on private land and car parks on which there is case law.

Other countries don't necessarily worry about having the stripes aligned in this way, preferring to mark in the way my non-conforming example has been marked. Here's an example from Maastricht in the Netherlands, although stripes are used at signalised crossings too;

Or how about this Swedish version from Malmö where the stripes are rectangular, but offset as they go across the road!

Saturday, 28 December 2019

The Predictable & Lazy End Of Year Roundup: 2019

It's that time of year between Christmas and New Year where I'm having a rest from life and reflecting on the year just gone.

Actually, it has been a tough year for me personally. At the end of June, I said goodbye to working in a authority highways department; I job that I had loved for most of the proceeding 15 years with a step into the unknown world of being a consultant. I do very much miss the people I worked with and I really miss my cycle commute which put me in touch with my local area as well as the changing seasons - although I still have a daily cycle to my local station and back.

The change came as a result of the London council elections in May 2018 where the administration took a distinct shift away from any interest in walking, cycling and safety. Formal decisions started to take months to get made by the political side and staff were often under pressure to change their advice with little apparent support from management.

Towards the end of 2018 I was introduced to my now employer and after a bit of toing and froing it led to me handing in my notice at the start of April this year. My immediate (temporary) boss completely understood my decision, but they also quit and left before my notice ran out! I was left drifting without any real support for those weeks and senior people didn't even make a half-hearted attempt to try to convince me to stay.

Six-months into my new role, I'm no longer stressed and I'm immersed in engineering again which is an absolute joy. I've also got managers who are genuinely interested in my welfare and I'm working with a bunch of people who have made me feel welcome. I realise that all of this stuff is relative and there are many, many people in this country who are far worse off than me. I am thankful for how 2019 turned out, although goodness knows where 2020 will take the UK.

Enough self-pity, on to the roundup.

My 2019 started with a statement: cycle tracks should be laid in red asphalt. Some have disagreed, but they know deep down that I am right.

Red asphalt in Utrecht. Correct colour and material!

I then took a look at crash-friendly infrastructure on the high speed road network. Next up, a look at some of the costs associated with building cycling schemes.

January ended with the first of two posts on what I called "partially protected turns" which are layouts we can use to protect left turning cycle traffic when we can continue cycle tracks round a corner.

The month started with the second post on partially protected turns and following that, I made the mistake of having sympathy for people "caught" in a Chelmsford bus gate - most of you had no sympathy!

A partially protected turn layout

Many people are against the new micro-mobility ideas, but I think we should embrace the little wheels!

My last post of February considered ways of managing freight and loading in our urban places - there is no single answer of course.

The start of March was all about a terrifying crossing of a dual carriageway which shows that there are some old habits which die hard in UK road design.

I was asked how people can become highway engineers and for me, the easiest way to explain it was with my story (it's been a year about my story one way or another!)

I then noticed a curious little bit of kerb detailing on a vehicle crossing which was worth highlighting because nothing is new in highways. Then a look at the different ways we can control parking on an area-wide basis.

Keeping the footway level at vehicle crossings

The annual ALARM survey saw a mixed picture on the condition of our road asset.

The month started with a visit to the Traffex trade show which I last covered in 2015.

Next I looked forward to a possible footway parking ban in Scotland followed by a short post on making a car park hump in a narrow park access road cycle friendly.

Francis Road in Waltham Forest was the subject of the final post of the month and certainly my favourite street of 2019.

Francis Road

The month started with a look around London's Olympic Park which is mainly awful for cycling, but it has some hidden gems.

Scarlett Close, a hidden gem

A welcome return to Stratford in East London to look at the completed works to remove the gyratory was up next, followed by a practical look at incorporating loading into cycling schemes was next - it's about what we want to prioritise of course!

Something must be done near schools to make the streets safer, but much of what we do treats the symptoms and not the causes was the theme for the end of the month.

I started June with a look at A-road engineering and wondered why we keep the approach as we head into our urban places.

Taming A-road engineering

My first visit to Judd Street and Midland Road in Central London was followed by a look at why we make people wanting to cross the road wait so long at traffic signals with another slice of Traffic Signal Pie.

With the news that the Mayor of London was to push ahead with the Silvertown Tunnel while canning the Rotherhithe walking & cycling bridge, I suggested that we should repurpose the venerable Rotherhithe tunnel.

I rounded off the month marking the end of my long stint in the local authority highways office.

I started the month pondering the difference between cycling in the rural areas around Harwich (UK) and Hulst (NL) followed by a review of the Dutch CROW Design Manual for Cycle Traffic (which was an eye-wateringly expensive acquisition).

Rural cycling near Hulst

I reported from the Cycling Embassy of Great Britain's 2019 AGM in Cardiff with some cycleways under construction following by a look at the Greener Grangetown project in the city.

The month started with my third and final report from the CEOGB's 2019 AGM where I responded to some questions posed by Cardiff's cabinet member.

Then a look at options for crossing big roads, rivers and rail - something that the UK really doesn't get, despite some tantalising attempts in the past.

Different options for going under

The #LondonCycleSafari rode again with a trip along part of Quietway 14, followed by another look at Midland Road by Kings Crossing Station in Central London. I ended the month with a search for a bit of peace.

I got the month off to a start with tales from Luxembourg City, one of the places I visited for my summer holiday this year and this was followed up with possibly my favourite post of the year was a look around the Vauban neighbourhood in Freiburg, Southern Journey. I had read about the experiment in low car living and it was wonderful to experience on a cycle.

A scene from Vauban

Some thoughts next on the Global Climate Strike and the difficulty of rationalising it with my own work as an engineer. Then my final post from my summer trip, I continued my look around the wonderful Southern German city of Freiburg.

The month started with a little post on Lamlash Gardens, a tiny corner of London that I had cycled past many times but never noticed.

Lamlash Gardens

Little did I know that Chapter 6 of the Traffic Signs Manual would be out before the year end, but it didn't stop me decrying the paltry amount being invested by a government obsessed with training.

I took a moment to revel in the joy of seeing more and more cargo cycles in Central London following by a quick look at how the Design Manual for Roads & Bridges was being updated to end the month.

A Christiania cargo trike

The month kicked off with a look at the unusual "dog bone" interchange and how it might be a useful layout to use for incorporating walking and cycling into free-flow trunk road style schemes. This was followed by
a long-overdue slice of my Traffic Signal Pie series looked in depth at pedestrian crossing push buttons and how we might do away with them.

A dog bone interchange

Next was an in-depth look at CD195 - Designing for Cycle Traffic which took an earlier Interim advice Note and made it a full part of the Design Manual for Roads and Bridges, although technically it only really applies to England.

I scorned the nonsense that is the Dutch Reach, a technique for opening car doors to help people to avoid hurting people cycling. I prefer to change the streets. I rounded the month of with a look at how low bridges are signed and how we might mitigate bridge strikes.

At long last, the government published Chapter 6 of the Traffic Signs Manual which was the missing bit of guidance following the overhaul of the traffic signs rules in 2016, but then we elected a Johnson which led to a bit of navel gazing at the UK general election.

The year ended on a high note with my post about the UK finally getting a home-grown inritbanden or "entrance kerb" which will make the detailing of continuous footways and cycle tracks so much easier.

Entrance kerbs in action

Saturday, 21 December 2019

The British Entrance Kerb - An Exclusive Introduction

I first went to the Netherlands in the early 2000s which was a decade before I became interested in how streets fit together, including the civil engineering elements that go into them.

In 2015, I made my return for a flying visit to attend a job interview where I got to look at how some of the Dutch street features worked. Of course, the country has a whole system approach to streets which has taken me a few more years to start to understand.

In 2017, I returned for a long family holiday where we spent three weeks touring the country and following which, I wrote eight blog posts examining what I had seen. That trip allowed me to start to understand how things worked from a user level - I am a strong advocate of experiencing engineering as a user of the end product.

It was the 2017 trip which really got me fired up about a couple of kerb designs; forgiving kerbs between footways and cycle tracks which have a gentle angle and low kerb height to stop wheels and pedals getting caught; and special ramped kerbs which allow us to keep footways and cycle tracks running at the same level through side streets (continuous footways and cycle tracks) and vehicle accesses by making drivers drive up and over them. It is the latter which I am interested in for this post.

Ramped kerbs (dark grey) to the left

The Dutch most commonly know this as inritbanden (roughly translated as entrance blocks) which I covered in detail in this post. It's not just about the ramped (and forgiving) kerbs, the Dutch approach relies on contrasting footway and cycle track surfacing and the side streets being filtered to promote low traffic neighbourhoods.

The UK has started to adopt Dutch techniques, but we have struggled to get our side street entrances right because of a lack of appropriate, off-the-shelf kerb elements. We have tried hard, but we invariably end up dipping the footway/ cycle track to accommodate side street traffic such as Magee Street in Kennington, London;

The alternative is to try and build a ramp which doesn't look like part of the road because we want to provide "visual priority" for people walking and cycling such as Angel Way in Romford, London;

Both examples kind of do the job, but they're compromised. We need to copy the Dutch! In April 2018, I released what is essentially an expansion of my most popular post - Kerb Your Enthusiasm, as a design guide to UK kerbs and how they can be used through my micro-consultancy, City Infinity as "The Joy of Kerbs" (or the Kerbasutra as a former colleague calls it).

In The Joy of Kerbs, I proposed ideas for a British version of the forgiving and inritbanden kerbs, with the latter captured as a concept sketch. Essentially we need two units; one is the ramped block and the other is a transition or corner unit which allows the system to match in with standard kerb products.

I can't recall exactly when (sometime last year I think), but I had a call from the specification team at Charcon (part of Aggregate Industries), which manufacture kerbs and paving units, with a request for a meeting because one of their directors was interested in the inritbanden idea. The interesting thing about Charcon is they have made kerb units for some of Transport for London's cycle superhighway schemes such as this unit to provide a divider between the cycle track and carriageway;

They also developed a sloping kerb with Cambridgeshire County Council which has been used on some stepped cycle tracks and which I covered here.

The specification team at Charcon are really interested in how this stuff fits together, but they have to be commercially-minded and so we essentially had an idea they were interested in, but it needed a scheme which would pay for the development costs. Concrete kerbs are cast in moulds which need to be designed and fabricated. Sadly, I was still in local government with an administration which had no interest in changing the borough's streets.

Things went quiet until earlier this year when I had request for another meeting with Charcon where I was told that the company was seriously looking to develop a product, but they were still looking for a project. I happened to mention that I had recently seen a proposal for the redesign of Chapel Street in Salford which looked like an ideal location for the product and I offered to put them in touch with Catriona Swanson, who was with Salford City Council at the time and she had talked about the project on a site visit with the Cycling Embassy of Great Britain's AGM in Manchester in 2018.

It turns out that Charcon had already spoken with Salford, but with Catriona's help, people were put in touch once more. As the weeks went by, I ended my local authority job and started my new one as a consultant and another call from the guys at Charcon saw me meet up with one of the team. The hot news was that the kerb units were almost certain to be taken forward with Salford, subject to a few caveats. I was sent some engineering drawings of the units, but I still couldn't say anything specific, although I did drop some hints on Twitter.

Some will have noticed a tweet about Charcon's website being updated with a new page showing a new product - Dutch Entrance Kerbs. Sharp eyed followers will have noticed some familiar photographs and a sketch of a Dutch side street - a little helping hand from me because the product literally hasn't been made yet! We debated the name of the product and agreed that "entrance kerbs" was probably the best translation to settle on. Of course, there needs to be a hook (of Holland if you will) and so the Dutch Entrance Kerb was born. I also helped out with the description, so blame me if it isn't right.

Last week, I had another catch up with the guys from Charcon - it's a go, the UK is getting a desperately needed addition to its streets toolkit with work starting on site next year. What's even better is that I'm now able to write this post because I have been desperate to tell the story! Even better than that, I have permission to talk about the dimensions of the units which means I can give some examples of how they can be used. So, onto the technical stuff. Before I go on, I must pay tribute to Charcon and Salford City Council for making this happen - the hard work of development is all theirs!

Let's start with a sketch of the units. We have the main ramped unit and the transition/ corner unit. Both are 500mm long (along the line of travel) and 750mm deep (cross the line of travel). The back of the kerbs (furthest away from the road) are 215mm high and the front is 150mm.

This means that the height difference from front to back is 65mm and so when used with ordinary kerbs, we'd generally set the kerb face of the cycle track (or buffer - more later) at 65mm (so 150mm is buried below road surface level). If my maths is correct, this means the kerb slope is a touch under 1 in 12. This is a useful gradient because it's one that most wheelchair and mobility scooter users will be able to traverse over a short distance. This is not a product intended for pedestrian crossings, but some people use dropped kerbs as crossing opportunities. 

The first 150mm of the corner unit is full-height (65mm kerb face) ramping to zero and the full height section runs diagonally over the next 350mm to give the distinctive shape which is far more elegant than my initial sketch! So, how do we use the product? The units are designed to be used with the square-edged variant of Charcon's Eco-Countryside range which has an attractive black fleck;

The other nice thing about the finish is that it's a little bit rough which is good for grip for those passing over it (whichever mode). The square kerbs which work with the system are the standard UK 914mm long (3 feet) and 145mm wide or an attractive 290mm wide. There's also going to be a 500mm by 500mm (on plan) unit which makes the unit a buffer in its own right, although in practice, standard kerbs might do the job. Charcon tells me that they are working on ordinary versions of the unit to be compatible with standard UK kerbs, so watch this space.

Let's look at some possible applications. First, here's a Dutch-style layout with a continuous footway and a continuous (one-way) cycle track. There is a very narrow buffer strip between the cycle track and the road which is 750mm deep - the same as the entrance kerbs. I have used the standard 145mm kerbs either side. You'll also note tactile paving for the footway because visually impaired people need to know when they are entering an area that traffic might be crossing - remember though, this is for a low traffic side street - busier junctions need different arrangements.

We can of course make the buffer much wider. At around 5m, we provide space for turning drivers to pause before or after the cycle track to give way to cycle traffic/ pedestrians or general traffic respectively. The Dutch would tend to have grass verges either side of this layout which provides space for trees, lighting, sustainable drainage, floating bus stops, parking and so on;

If space is tight, then, the units could be used with the 290mm wide kerb to provide a simple (if narrow) buffer;

Of course, this is a compromise for cycle traffic, but it might be a helpful way to maximise usable width for the majority of a link - it is necessary to make sure that the slight narrowing is conspicuous day and night, although there is mitigation as people tend to keep left on a cycle track unless overtaking. Of course, we can run this the other way round with the ramp into the carriageway;

Again, care is needed to make sure this is conspicuous day and night because it does present a safety risk to general traffic.

The units are very heavy, approaching 200kg so they will definitely need mechanical assistance for installation, but they should withstand some abuse. In terms of installation, they will need to be bedded on kerb-mix concrete - it's usual to use 150mm of bedding which is probably fine with these because the real support comes from the bearing strength of the ground below. In any case, you will need to employ a competent designer for the layout and structural design.

So, what's next? I'm hoping to visit Charcon's Derby factory in the new year when the units go into production and I'll blog about that. I'll also keep a beady eye on Salford for when work gets underway at Chapel Street (assuming nothing changes in the meantime).

For me, this year has been a challenge and so it's been brilliant to be able to round it off with this post because I genuinely believe that this product is a game changer. I have also floated the forgiving kerb idea and if someone has a scheme needing about 500 metres, then let me know and I'll put you in touch with Charcon.

I should say at this point that I have no affiliation to Charcon, but they are genuinely interested in how things work, so I hope this product takes off. A big shout out to Charcon's national specification manager, Clinton Young and specification manager, Gavin Fancote for being interested in this idea and for being instrumental in making it become a reality. Thanks also to whoever in Salford City Council who saw the benefits and thanks again to Catriona Swanson for the scheme inspiration on the tour of Salford.

Next week's post will be my usual lazy and predictable roundup of 2019, so it just remains for me to wish you all a very merry Christmas and a wonderful new year. See you in the saddle.