Saturday 1 April 2017

Drawing Parallels

As of March last year, we were given a new tool in the highway engineering box and we are starting to see them popping up - the parallel zebra crossing.

The changes to the UK traffic signs rules; the Traffic Signs Regulations & General Directions 2016 (TSRGD2016), brought parallel zebra crossings into being, although a couple of local authorities did sneak them in before they were properly lawful. You may also be interested in this old (unpublished) study commissioned by Transport for London which looked at people using zebra crossings on bikes. The definition of a parallel crossing is as follows;

OK, it's legalistic, but essentially it defines it as a zebra crossing which everyone will be used to with Belisha beacons (the flashing yellow globes on black and white poles) and black and white stripes on the road for pedestrians;

The bit that makes it "parallel" are the "markings provided in item 57" - that is the large square "elephant's feet" markings. As an aside (b)(i) has an interesting point about a parallel crossing going over a cycle track not needing the globes. A parallel crossing over a cycle track is quite a thing and I am not sure anyone has done this yet! Anyway, the "elephant's feet" look like this;

The above mentions "item 28" and this is the familiar cycle road marking (it is optional, but I think it's worth using);

The general layout is as follows;

OK, I've zoomed in and spun the layout round to make it more like what people walking and cycling would see;

At the moment, we don't have any guidance on how the crossings should be designed, this will (hopefully) be included in the new Chapter 6 of the Traffic Signs Manual which will deal with "traffic control" - most of the other chapters are currently being rewritten to reflect TSRGD2016.

Parallel zebra crossings operate in exactly the same way as ordinary zebra crossings do in that drivers (or cyclists) on the main carriageway have to stop (and be prepared to stop) at the crossing give way lines to let people on the crossing, well cross;

In other words, if someone has stepped onto the crossing, they must be allowed to cross and if someone has cycled onto it, they must be allowed to cross too. There was a concern when parallel crossings were proposed that we'd end up with people cycling straight out across them, heedless of traffic. It's a theoretical issue, but the general approach is that those about to use a crossing should have an awareness of the traffic and act reasonably. In practice, I think the issue will be the same as pedestrians experience and it will be poor driver behaviour being the issue.

Until we get the new guidance, I think there are some principles we should consider;

Speed on main carriageway
As with ordinary zebra crossings, parallel zebra crossings are not suitable for roads with traffic speeds about 35mph. Even if there is a 30mph speed limit, it doesn't follow that this will be the speed at which drivers choose to travel.

There needs to be reasonable visibility. This obviously applies to drivers (and cyclists) on the main carriageway being able to see people about to cross, but people cycling will not be standing close to the kerb, they will be sat further back. People riding adapted cycles and non-standard will be say even further back. For example, when I sit on my cargotrike, my eye position is about 1.3m from the front of the box and I'd sit back from the kerb a bit too.

Level crossing point
As with ordinary zebra crossings, we can place parallel zebra crossings on a flat-topped road humps. This means that people won't have to drop down into the road and then back up the other side which reduces comfort and convenience, especially for people riding adapted and non-standard cycles. Making the crossing experience better for people who might suffer pain with bumps or struggle with slopes will make the experience great for everyone.

Avoid convoluted turning
A few of the parallel zebra crossings I have seen (and experienced) require people cycling to turn at the last minute in order to cross the road. Where the cycle track runs parallel to the road (be it shared with people walking or a separate track) it will require people to look over their shoulder if they are cycling in the same direction as traffic;

The photo above is of a parallel zebra crossing at Marshall Road, Waltham Forest. For people coming towards the crossing parallel to traffic (where the car is in the photo), they have to look over their shoulder as they approach the crossing. A buffer has been provided between the road and the cycle track in an attempt to have people on cycles approaching perpendicularly to the road, but it is not quite wide enough. In mitigation, the crossing is on a hump and the one-way road is narrow to keep driver speeds low.

Where a parallel crossing is used on a cycle route which crosses a road, the arrangement works better because people arrive at the crossing perpendicularly to the road like this example from Hackney where Martello Street meets Richmond Road; 

OK, it's not quite perpendicular, but you don't need to look over your shoulder to cross the road. The cycle route has been there a long time and the "give way" sign is a remnant of when people cycling had to give way to traffic. The parallel crossing here has also benefited people walking.

Parallel means exactly that
There is one very annoying thing about parallel crossings - they have to be parallel! This means that if the pedestrian and cyclist desire lines are not the same you can't adjust them to suit. The stripes and elephant's feet are set in the regulations as being 400mm apart which is also a pain.

Think about how people walking may be confused
Visually impaired people require tactile paving to assist with crossing the road. We shouldn't be placing tactile paving on the cycle part of a parallel crossing and so this all needs careful thought to make sure that we don't create confusion for people on foot because at worse, we could be leading some people into a trap.

The photo above is the view from Clapton Square in Hackney, across Lower Clapton road. In this example, pedestrians leaving the side road on the left footway would have the pedestrian part of the crossing in front of them on the left side of the photo and a kerb if they left the right footway. For visually impaired people, this is an important design feature. The other thing just to note with the crossing above is that there is a refuge, but it is rather narrow for cycles.

I also think that maintaining the footway helps explain to people cycling that they do have to cross pedestrian's space before they get to the crossing.

Tidal traffic flow
As with ordinary zebra crossings, if traffic flows are heavy in one direction, then there is a risk of people being "masked" as they cross between the slow moving vehicles into the free-flowing traffic stream. Notwithstanding the fact that drivers (and cyclists) using the main carriageway should expect to see people crossing, this is still a safety risk. We sometimes mitigate this with a refuge (meaning the crossing is treated as two, distinct parts), but with some cycles being very long this is going to be less practical. In those situations, we need to push the distance between the stop line and the crossing position towards the 3 metre maximum to give maximum visibility.

It should go without saying, but lighting at night is crucial for safe operation. Specific zebra lighting should be used which Illuminates the verticality of people, rather than on plan.

Local education
It's not really a design principle, but the new crossing has been released into the wild with no national marketing campaign. Compare this with the current campaign to educate motorway drivers that they shouldn't drive in a lane with a red 'X' above it. I assume it's the usual government leaving it to local authorities plan, so perhaps there needs to be local publicity to explain how these new crossings work.

That's my general thoughts on how we should design parallel zebra crossings, but I I think some sketches might also help. First, the sketch below shows how I would lay out a parallel zebra crossing where a cycle track route crosses the road. The crossing itself is humped (zig-zags omitted for clarity) and the track stepped below the footway running left-right. Because of the step, there is a very gentle ramp up to the main footway which is continuous across the track.

A variation on this will be the crossing at Clapton Square which connects a side road (Clapton Square) to a cycle track on the other side of the road. We can take the opportunity to connect the route with the crossing and perhaps provide some landscaping within the closed side road;

We can go a bit crazy and have all traffic coming out of the side road, but let's make drivers turn left;

OK, the last one might be a bit more tricky as to get into the right position to cycle right to left, one would be taking the lane in the side road (which would be fine in a quiet street). My point is there are lots of options and of course each situation would be different. The next level up would be using a series of parallel zebra crossings on a roundabout, but you'll have to wait until Cambridge builds the first one to see that let loose on public roads!

Update 2-4-17
In response to the question below about giving pedestrians priority across, I guess we could do something like the sketch below, but it seems over the top to me. How do we get some people on bikes to slow down for people on foot? Welcome to the world of design!


  1. Just a quick question - do you have an estimate as to how much it costs to install a parallel crossing (presuming a road with a 30mph limit and street lighting)? I proposed one for the A10 cycle scheme in Melbourn (Cambs) a few months back, but it was knocked back on the grounds of cost. (Actually, a series on the cost of public works more generally would be really interesting and helpful - we often have to explain at public meetings why a mile of new cycle path costs as much as a four-bedroomed house...)

    1. It depends on the approaches of course, but £20k - £30k would be about right (including design costs). At the higher end, we'd have a humped crossing.

    2. Or, to put it into context as you have done before, somewhere in the order of 500 mm of A10, 50 mm of M11 or 5 % of a set of motor traffic lights?

      Mike P-J: it's not your job to explain such things at public meetings and potentially harmful. Please try to resist the temptation. If you really must rise to the bait, tell the trouble-makers the name of the permanent civil servant whose job it is to explain their profligacy.

      Ranty: Why are the ramps on the carriageways in your diagrams twice as ‘very gentle’ as those on the cycleways, assuming that both start at the same height? WRT. the last diagram, if someone is not going to yield to a naked footway then they probably aren't going to for some mini-stripes either, just as they wouldn't for the Zebra—with full-fat stripes, flashing knobs, zig-zags, etc.—if they were a motorist on the carriageway. Or loiter on the Zebra itself if someone started crossing the far-side mini-stripes in the interim! Proposed alternative solution: a couple of metres of those level-crossing pyramids on the footway either side of the crossing to deter walking 😖. Then simply ‘bend in’ the [now necessarily advisory] walk lane into the carriageway so that walkists are obliged to give way to those using the crossing… You can probably imagine where I am heading with this? BTW, how come we are told those mini-stripes are ‘impossible’ when it's a general-purpose side-road and why don't we have them at every single junction without continuous footways, too?

    3. The ramps are diagrammatic - MS Paint is not a CAD package! I'd say the cycle ramps should be no steeper that 1 in 20. The last image was in response to a question and I certainly wouldn't do it as it's well over the top!

      Zebra stripes without Belisha beacons are permitted on cycle tracks, but not carriageways and so zebra stripes at side roads would need beacons too. Pedestrian deterrent paving - urgh!

    4. If you tried to pull that ‘not to scale’ stunt on a planning application; most councils would file it straight in the bin, after banking the fee of course! Instead of a maximum gradient which you likely couldn't achieve on a slope anyway, please specify one sag K-value for all ramps such that there is never more than one contact patch with a [round] tyre—including the front wheel of an ordinary. See NL for details.

      The level-crossing pyramids—and the ‘bending in’—is easily and cheaply avoided: merely extend the Zebra and give-way lines across the perpendicular footways (or mini-stripes at 90° to your diagram)… Anonymous would then have to wait their turn if someone was crossing—even, shock-horror, on a pedal cycle 😱.

    5. :D essentially, I had in mind a 30mm step between the track and the footway, so a long ramp is fine. In the example from carriageway level, the hump could be no more than 100mm and should always be sinusoidal.

      Priority is the fun thing, but we can't expect people on foot to be subject to give way lines. I think the way Hackney has done it seems fine.

    6. If they won't comply with give-way lines, then automatic crossing gates/ barriers it shall have to be! You said ‘the most vulnerable should have primacy’. That is not the walkists on their own dedicated stepped infrastructure. It's not the walkist on the carriageway part of the Zebra, who have tens of square metres of stripy paint—and, as Anonymous [almost] concedes, undoubted legal priority. It's not even the equally vulnerable walkists or cyclists on the mini-stripes part, no matter how much Anonymous (and you?) would like to drive a wedge between them. It is the cyclist on the carriageway part of the Zebra, with only a few measly elephant footprints and where Anonymous opines that it is ‘uncertain’ whether motorists would bother to give way. The last thing those cyclists need is conflict designed in at each end as well. The real change in attitude needed is for carriageway users to start thinking; I cannot yet tell whether there is anyone approaching that crossing, possibly at cycling (or running) speed, therefore I'd better lay off the gas so that I can stop in time if there is. As would be required on a motoring test?

      If the ramps are intended to be noticeable, even at 30 mm difference (300 mm better, to discourage walkists from intruding on cycleway), then they need to be steep enough to accomplish that at the inflection point. But not to impart any impact damage or make them uncomfortable for all. Double Dutch half-humps? It is exceedingly rare for UK contractors to get the sinusoidal profile & length right (working from ‘diagrams’?) or project managers to insist on epic fails being corrected. Exactly the same applies to humps on the carriageway—including intended speed. There will be people cycling there, too.

    7. Thank goodness we never got those barriers!

      Sinusoidal humps are not too difficult to get right, but you need a good construction crew.

      I guess the problem with all of this is "we" know about pedestrians and we know about pedestrians, but who are these interlopers and how do we adapt what we know about the other two modes which can be bolted on - lack of decent UK design layouts doesn't help.

  2. I've seen some red circular 'cyclists wait here' signs next to these crossings, and wonder what the legal status of that is. I'm fine with slowing down and crossing cautiously, but if you stop and wait then you lose your priority, which only exists if you are actually on the crossing?

    1. I forgot to mention that I have doubts whether cyclists have in law priority even when on the crossing in the same way as pedestrians. While para. 22 of The Traffic Signs Regulations and General Directions 2016 (quoted above) provides the meaning of the markings, I have yet to find legislation which adds to or amends the law which gives pedestrians precedence on a crossing[1]. I am also awaiting a reply from Hackney Council on this point given their signs.

      [1] The Zebra, Pelican and Puffin Pedestrian Crossings Regulations and General Directions 1997 (SI 2400/1997)

      "Precedence of pedestrians over vehicles at Zebra crossings
      25.—(1) Every pedestrian, if he is on the carriageway within the limits of a Zebra crossing, which is not for the time being controlled by a constable in uniform or traffic warden, before any part of a vehicle has entered those limits, shall have precedence within those limits over that vehicle and the driver of the vehicle shall accord such precedence to any such pedestrian."

    2. Except the ZPPPCRD97 are revoked;

      12. The General Directions specified in the table in Part 2 of Schedule 19 are revoked.

      The table is on p545 of TSRGD16 and this confirmed the revocation of the 1997 regulations. So, the priority as I have referenced is now the law!

    3. Oh and the signs - no legal significance, so caution by the LA perhaps?

    4. Thanks. Shameful mistake by me not to check the revocations. I can only plead in mitigation that the Highway Code still cites ZPPPCRD97 nearly 6 months after the transitional saving expired.

      That said, the corresponding provision seems now to be in Schedule 14, Part 5 (Movement at section 25 crossings) on page 496. But that still only deals with pedestrians (“7.—(1) Every pedestrian who is on the carriageway within the limits of a Zebra crossing, …”.)

      Sorry if this is nit-picking but I’d like to know where the law stands as cyclists are in practice justifying their speed across the footway on the basis that the law means there’s no need to slow down for the parallel crossing.

    5. I think the answer is that Part 5 does indeed replace ZPPPCRD97 in respect of s.25 crossings (Puffin and Zebra), but that the (very similar) provisions for Parallel crossings are actually found in Part 1 s.21-24 and do give cyclists exactly the same rights in the cycling part as pedestrians have in the Zebra part. Meaning that, technically at least, road traffic has right of way if it noses into the zig-zag area before the cyclist's front wheel enters the carriageway by touching the kerb?

  3. 2 comments - both drawing on experience as both driver and pedestrian of the parallel crossings in Hackney (especially the one now in Morning Lane, similar to that at Martello Street).

    1. What about pedestrians using the footway parallel to the road? They had problems before the parallel crossing with cyclists emerging from the cycle path. Now some (during commuting hours, many) cyclists just cycle straight across the footway without slowing. I have heard a mother tell her child "there's no need to slow down, it's our right of way". Morning lane has no “give way” markings for cyclists – marking which AFAIK are not enforceable (and rarely observed). What thought was given to contention between cyclists and pedestrians on the footway? Or was it accepted that would assume and assert priority?
    2. You state that “the issue will be the same as pedestrians experience and it will be poor driver behaviour being the issue”. In my experience as a pedestrian of 66 years and a driver of 49 most drivers are ready to stop for pedestrians at or approaching a crossing, and most pedestrians approach a crossing with common-sense – eg they don’t expect to *run* straight across a pedestrian crossing from an alley so drivers have limited visibility. Yet that is what I have observed cyclists do with pedestrian crossings for years; which parallel crossings in Hackney seem positively to encourage them to do; and where the law seems uncertain. Eg is a cyclist travelling at 20 mph entitled to cross without pausing, and without regard to traffic on the road?

    1. The general principle of zebras and now parallel zebras is that people shouldn't just blast out onto the crossing, heedless of traffic; plus there is a requirement for people on the crossing not to loiter.

      From a cycling point of view, one should approach the crossing (to cross) with care - to go straight out at full speed is reckless and there needs to be the cultural shift. The alternative is a Toucan which is of course far less flexible.

      The bit with pedestrians having priority on the crossings I have mentioned and my sketches follows the principle that the most vulnerable should have primacy and again, there needs to be a shift from the full-pelt mentality. Nothing would stop you having a zebra across the track (without beacons) which I have added to the end of the blog, but this does seem over the top to me.

  4. I've not seen those signs at parallel crossings. But pedestrians face exactly the same issue. They resolve it in practice by waiting or just slowing down) until they are not stepping out in front of a vehicle which has no time to stop (allowing for thinking time). Hence Highway Code 195 includes "look out for pedestrians waiting to cross and be ready to slow down or stop to let them cross".

    Sorry to posy anonymously but the site seems to reject my IDs

  5. Why would you have a parallel crossing of a cycle track? If it's not by a road, surely just mark it as a junction?

  6. I have a parallel zebra crossing on my commute (on Huntingdon Road, Cambridge) and although it's not perfect, it probably saves 30 seconds compared with the alternatives (of having no crossing, or a light-controlled crossing). I slow down or wait until I am sure that approaching traffic (both cyclists and motorists) is going to stop, and it always does so.

  7. This one in Bristol pre-dates the TSRGD 2016 by about a year, I think. It omits the parallel track and simply uses a wide crossing.,-2.5936887,3a,75y,139.63h,66.19t/data=!3m6!1e1!3m4!1s7tJxsGUvkmiWt7H64D-8VQ!2e0!7i13312!8i6656

    Check this out, also in Bristol, installed at least 4 years ago. Not a crossing exactly - more of a crossroads where two routes intersect.,-2.5927878,3a,75y,180.96h,69.62t/data=!3m7!1e1!3m5!1s9_JqwTb5W2EKupcubCv-tg!2e0!5s20121001T000000!7i13312!8i6656

    1. They should probably tweak the zebra now! The second layout has been allowed for years - don't need to have it on a hump now (but I think it's a good idea to use the hump to slow drivers and make a smooth cycling transition!)