Sunday, 16 June 2019

Traffic Signal Pie: The Long Wait

So this week, I was inspired by Brian Deegan to go and time how long it took to get a green man/ cycle at a 2-stage toucan crossing I use twice a day.

To be honest, it wasn't quite as bad as it might have been with a 45 second wait for the first half and a 25 second wait for the second half;

For those who are interested, the location is here. The interesting thing about the crossing is it was one of the things that enabled me to start cycling to work in 2011 because it just used to be a pair of dropped kerbs on each side;

The provision of a signalised crossing along with shared-path widening and the adding of a 2-stage toucan at another junction all worked to make my trip easier. It's all far from perfect, but it makes the journey possible. I digress.

The problem with my regular crossing is that the length of time it takes to get a green leads to a couple of scenarios because of the traffic flow on the road it crosses. On one side of the crossing, it's a bit harder to see the gap in traffic because of the speed of vehicles leaving the adjacent roundabout, but there is never slow moving traffic. 

On the other side, it's either absolutely deserted and so there is no need to wait for a green and sometimes it's pretty much stationary which leads to the quandary of crossing between two lines of traffic or push and wait for a green. Driver behaviour is variable with some leaving the crossing clear and some blocking it and with the risk of motorcyclists filtering between the two lanes. I often press the button and wait for a green so I am sure because it is often the case that one lane is moving and the other is not which means (depending where I am crossing from) that I am masked from drivers in the moving lane.

So, am I just a whinger? The journey usually takes a sedate 25 minutes and if it takes a couple of minutes to cross, so what? Am I more important than the drivers I am stopping to cross the road? The thing about traffic signals is that they are not a safety device, they are a traffic (in the widest sense) management tool. They are used to help people cross or join the main traffic flow whether on foot, cycle or in a car. They work if everyone obeys the rules, but the outcome can be catastrophic if someone doesn't (with the risk being higher from drivers of motor vehicles).

There is more detail in the guidance (LTN 2/95), but essentially, where traffic speeds are lower (85th percentile being under 35mph), then the green man/ cycle can be set to come in quickly (although the 20 to 30 seconds advice is still too long, it can and should be quicker). With higher traffic speeds, then the crossing will need speed detection.

On a 30mph road, needing speed detection admits there is a speeding issue and so speeding is rewarded by the crossing controller ensuring that approach speeds aren't too high. Speed detection can actually help reduce the time for a green man/ cycle of course when approach speeds are low and it is safe to bring in the crossing stage nice an early. Speed detection used to comprise of loops cut into the road and physically connected to the crossing controller which is very costly, but the technology is now allowing wireless detection which is far cheaper.

If we have the crossing connected to an area traffic control system (such as SCOOT), then waiting times might be even worse because the green man/ cycle is only coming in when it's not going to affect journey reliability time for drivers which is being monitored across an area. Certainly, my regular toucan is connected to SCOOT which is part of the reason it takes ages to get a green.

If someone is going to using a signalised crossing on a busy road, then the stream of drivers is going to be stopped at some point anyway, so wouldn't it make sense for the crossings to actually change quickly? the flip side of them not changing quickly is partly drivers seeing a red signal but nobody crossing (making red light jumping tempting) and partly people crossing because they are fed up with waiting and possibly not finding a safe gap (especially with children and older people having trouble assessing traffic speed).

It's also about respecting those travelling under their own steam and realising that their effort is significant in comparison to those driving. It's about time we started getting our priorities right.

Sunday, 9 June 2019

Judd Street & Midland Road

Between helping out with design workshops at the London Cycling Campaign's "Campaigner's Conference" yesterday, I had time to nip out to look at the newly remodelled junction of Euston Road/ Judd Street & Midland Road in Camden.

So yes, another post from London, but it's not an area I know terribly well and the layout is something which can be copied (mostly). Euston Road is part of the A501 which itself is part of the Inner London Ring Road and so an important motor traffic route which in theory should be more useful than the adjacent areas for through traffic. In practice, it's less clear cut, but at least where it is met by Judd Street and Midland Road, things have changed.

Midland Road runs up the western side of St Pancras International station and forms part of the road network which serves the station and the wider area. It is an important location for taxis picking up people from the station, but it is now a part of a cycle route north to Camden Town which at one point itself connects to Royal College Street - in other words, a cycling grid is starting to form.

To the south, we have Judd Street which connects to Tavistock Place which is another part of the local cycling grid and so connecting the areas north and south of Euston Road opens up all sorts of possibility for utility cycling trips.

Before the current changes, Midland Road was a southbound one-way street which flared out to 4 traffic lanes approaching Euston Road and one simply couldn't use it to cycle north (below).

Judd Street was open to all classes of traffic, although one couldn't turn right onto Euston Road. From what I understand, it was pretty busy and it is notable that the Royal National Institute of Blind People (RNIB) has its London office near the junction.

The new layout for Midland Road provides one-way stepped cycle tracks for each direction which change to island-protected cycle tracks approaching Euston Road;

As is becoming frustratingly common with UK cycle tracks, we have a vertical upstand on the kerb between the cycle track and footway, although at least it is low enough not to be clipped by pedals;

The old taxi rank layout has been kept and so there is a curious southbound arrangement with taxis on the nearside in a taxi lane and a cycle track next to it. This is because passengers will be getting in and out of taxis - it probably makes sense for the location, although taxi drivers waiting to move along did tend to stand on the cycle track while chatting.

At the exit to the taxi rank, drivers give way to people cycling and they should be able to see people coming, although having a conflict point isn't ideal;

About half way along the street there is a large zebra crossing providing access to between the Francis Crick Institute and the station as well as a floating bus stop. As can be seen below, there is a bus stand, then the zebra crossing and in the distance the bus stop.

The bus stand is poorly positioned because when it is in use, a parked bus will obscure the approach to the crossing for drivers and my view is that it should be pulled much further back and the island between the taxi lane/ cycle track and main carriageway made wider to help slow drivers down.

The zebra crossing itself is extremely wide, although I am not that convinced it needs to be. There is a risk in my view that a driver approaching may be concentrating on the area closest to them and miss someone crossing at the far end. The crossing stripes are paved in light grey and dark grey paving blocks which for my mind simply doesn't provide enough contrast between the black and white normally associated with zebras. A sufficiently contrasting carriageway surface is OK for the black stripes, but the white stripes need to be white (below). In addition, there are no "tails" to the crossing to help visually impaired people walking along the footway locate the crossing.

The taxi lane and cycle tracks are also paved within the limits of the zebra crossing and although they are installed with a grout, I predict they will fail on the main running carriageway which takes bus traffic (below).

Personally, I'd have liked to see red, machine-laid asphalt cycle tracks and ordinary asphalt for motor traffic, although the taxi lane paved in the blocks might have been a good idea given the amount of diesel sticking to them which would have destroyed asphalt. Hybrid taxis cannot come quick enough. One other little touch on the taxi lane is some raised blocks to provide a bit of traffic calming (below).

My criticisms to one side, it is still a good scheme and even on a Saturday afternoon it was being used which is as good enough verdict for quality if you ask me!

Heading southbound on Midland Road, a sign (aimed at drivers) explains that the ahead movement is for cycle traffic;

Approaching Euston Road (below), the cycle track gains an island for protection and the level drops down to that of the adjacent carriageway;

As is now the norm, we get a full-sized cycle signal for people approaching the junction and a low-level signal for those at the stop line; the green for people cycling runs with the pedestrian crossings over Euston Road;

For cyclists turning left or right there is a stop line on Euston Road just after the junction to control the conflict with people crossing - the main desire will be between Midland Road and Judd Street, so it's a reasonable compromise; plus Euston Road is pretty hostile for cycling so only the fit and the brave will be turning off;

Across Euston Road, we have Judd Street which is essentially now a narrow little junction for cycling. The view below is from Judd Street looking north and you can just see a driver thinking they are on a cycle;

It would seem that the very clear signage isn't quite enough for some people (below) and it would be solved with a couple of fire-brigade flexible bollards or traffic cameras (which keeps easy access for all emergency vehicles). Mind you, the "no entry, except cycles" isn't the sign I'd have used as it is generally for contraflow cycling on one-way streets; the "no motor vehicles" sign would have been better.

The yellow lines in the photograph above aren't quite right, they should stop at the red lines (for Transport for London's red route on Euston Road) and not go across the cycles-only junction. But, it's a small point.

The traffic signals again have a full-sized and low level signal and for left and right turns, we have the same stop lines because cycles go with pedestrians crossing (as explained above).

The cycle green is quite short and many pedestrians crossing Euston Road will only be able to make half the crossing in a single stage because priority is given to Euston Road.

There is a pedestrian crossing over Judd Street (as there is over Midland Road), although people tended to cross when they wanted which is largely fine. There is an issue with the tactile paving in that RNIB wanted the standard red for controlled crossings after it was put in as light grey. Dark grey has been installed which gives some contrast, but being near RNIB's office I cannot understand why red wasn't used. 

The photograph above also shows a little cycle symbol with a right turn arrow. This is because right turns from Euston Road are two stage so one would pull off the main drag to wait by the cycle symbol before crossing ahead with the next green stage.

One issue which I have since been made aware of is that there is no left turn from Euston Road into Judd Street because because the traffic signals show ahead only and the green on Euston Road runs at the same time as the pedestrian crossing over Judd Street as can be seen from this still from footage shot by Sea of Change Film;

As you can see the main traffic signal and supplementary arrow is for the ahead movement (westbound on Euston Road) and this shows green at the same time as the pedestrian crossing over Judd Street (both circled green). The guy circled red is using the footway to turn left into Judd Street.

There is a need for the left turn and most sensible people will realise that they are disobeying the rules and do so carefully, but someone not behaving is at a high risk of hitting someone on the crossing using the green man. This needs looking at and will be tricky given how the signals are set up. It's the same on the other side where one cannot turn left on a cycle from Euston Road into Midland Road.

I'll leave you with a short video of the 2-stage right turn from Euston Road into Judd Street;

Sunday, 2 June 2019

A-Road Engineering

I am probably stating the bleeding obvious, but the type of highway design one sees on trunk roads has no business going anywhere near a town centre.

For some reason, though, we see high-speed layouts plucked from a rural A-road and dumped in our urban places. The approach is partly a legacy from how people used to design urban roads, partly how casualty-reduction schemes are designed, partly because the wrong people are working on the wrong schemes and partly because of the reference materials for design.

Today, my family and I headed off to the coast and as usual, I couldn't switch my brain off from engineering (I don't even bother trying) and the A133 between Colchester and Clacton-on-Sea got me thinking. Look at this layout;

There is nothing unremarkable about this layout, it's standard. A National speed limit and sensibly, right turning drivers are separated out from those who will be travelling faster. Right turners complete their turn in two parts in a controlled way - move into the right turn lane and then when there is a gap, turn into the side road. The layout is popularly known as a "right turn pocket".

Guess what, we are not the only ones to do this, here's a similar type of road in the Netherlands;

It's a very similar layout to what we see in the UK and it follows the same principle of separating people moving at different speeds. The A133 goes right into Clacton, but we still see hints of the big A-road design approach;

Anyone familiar with the Design Manual for Roads and Bridges and Chapter 5 of the Traffic Signs Manual (below) will be familiar with this type of treatment;

The town section of the A133 shown above has been like it for years and while it echoes the rural A-road design, it's very much in an urban place and my gut feeling it is less about separating right turners from a high speed road design context, but probably more likely as a response to addressing right turning collisions.

This type of standard treatment is still taught on "road safety" courses and it is used everywhere. When someone relatively inexperienced has been put through a standard road safety course and been shown Chapter 5, I think it is pretty certain that this layout will be picked off the shelf to deal with right turning collisions. It is also used for traffic flow reasons to get the right turners out of the way of other drivers.

In the urban context, we have people walking and cycling. Notwithstanding the fact that if we have urban streets with high levels of traffic, we should be separating cycling; the right turn pocket makes it harder for cycling. For example, the lane width is being squeezed and with a right turning vehicle in the pocket or with refuge/ traffic islands, we get a pinch point for cyclists;

As you can see, when the right turn pocket is in use, a cyclist has to get through a long pinch point. The pedestrian crossing ahead is single stage and doesn't necessarily need the island.

We often do find pedestrian refuges associated with right turn pockets as they help define the space for the various traffic lanes, but they help people cross the road in two halves which creates a conflict between walking and cycling.

Turning right from side streets is also made harder as one has to now cross three lanes of traffic and in my example, right turns have been banned - probably because the right turn is is busy and right turns out would block the main road and there is actually a signalised alternative on a parallel street.

So what is my answer? Well, by all means, keep the A-road engineering out on the rural A-roads, but when we get into the urban realm, we need to change our approach. Putting walking and cycling to one side, a very good way of managing right turning conflicts is to use a combination of filtered permeability and traffic signals.

If we manage right turns into a filtered area with traffic signals, we can let drivers out of the same filtered area without controls. This works because losing the rat-running traffic actually means fewer people turning into the filtered area in the first place (so less chance of holding up other drivers) and with fewer drivers leaving the same area, less interactions with main road traffic;

The image above shows a couple of urban A-roads in green and residential streets in grey. The junction to the bottom right is a filtered cycles only access (to stop drivers avoiding the roundabout). The middle junction on the north-south road is signalised to manage right turns into the filtered estate and the other two junctions are no entry from the north-south road (with a cycles exception). As with many of our urban problems, we need to look at how the network is operating first and then design from there.

Monday, 27 May 2019

School's Out

It's the school holidays and so it might be worth having a whinge about the obsession that they have with two things we can add to our streets which don't really have much of an impact.

As I near the end of my local authority career, my anecdata would suggest that it is school warning signs and pedestrian guardrail which are the popular request from schools. I am not totally sure why this is, but perhaps;
  • they are relatively cheap wins which appeals to the "something must be done",
  • many teachers and head teachers are drivers and they come at "road safety" from a traditional motor-centric point of view (certainly an Outer-London perspective),
  • they are simple 'solutions' compared to lobbying for meaningful change, especially if schools have limited resources to campaign with.
Also, being truthful, for a local authority office, putting in signs or a bit of guardrail is equally easy as it needs no consultation, looks like something is being done and it gets the school off one's back.

Over on Twitter, we often use the hashtag #SignMakeItBetter and at schools, it's no different;

The photograph above is a school warning sign on steroids. OK, it warns of a school crossing patrol, but the "patrol" plate can be swapped for "school". Just look at it, flashing amber signals, bright yellow. Fantastic.

Even with a basic warning sign, it is fairly and squarely aimed at warning drivers that there is a "hazard" ahead - that's what the triangular sign means. There is a hazard ahead and you should modify your behaviour. Great, there are kids milling about because it is school time and they are a hazard to drivers. Can't we see how upside down this is? 

Warning signs are overused (at least in urban areas) to the extent where they are pretty meaningless. There might be some reactive value where a school is near a road with a speed limit of 40mph and greater, but other than that, it is reasonable to expect there are children walking to school twice a day in built up areas.

Guardrail is requested for three reasons - to stop people parking outside a school, to stop the little ones running out of the school gate and straight into the road and to stop drivers getting onto the footway (either parking or crashing).

As you can see from the photograph above, guardrail does not stop parking. In fact, it often means that children being dropped off leave the vehicle on the live traffic side and then walk along the road to the end of the guardrail. Of course, it stops parking on the footway, but so would some bollards, planters or trees.

As for physically stopping a speeding driver? Not a chance;

The most tricky one is using guardrail to stop the nippers running out into the road. I have yet to see any study which looks at the safety impacts of providing guardrail in front of school entrances. I think it's more about making people feel secure and to be fair, that's a perfectly rational safety argument - experienced safety. However, a school could equally place guardrail inside its premises to have the same impact and not take away footway space.

Perhaps a footway doesn't have enough capacity to contain the people milling around at school travel times and so some guardrail could help stop people (especially children) getting jostled into the road, although we set it back from the carriageway which means more footway lost. For me, the answer here is to make sure there is good capacity for people to get in and out of the school and if overcrowding is the issue, then more footway space is the answer.

The ultimate answer of course is to take the space outside the school away from drivers (school streets as they are often now called), such as outside Heald Place Primary School in Manchester (above) where a dozen bollards and a couple of traffic signs dealt with the problem which traffic calming, guardrail and parking controls couldn't.

Sunday, 19 May 2019

Practical Loading

The need for business loading is often cited as a reason not to build cycle tracks, but it's a spurious argument. 

Businesses absolutely need to move goods around to function and in fact, when we upgrade our streets to provide new cycling infrastructure, loading can be easily accommodated.

It's obvious I suppose, but for the foreseeable future, we are still going to be using vans and lorries to service businesses and we absolutely should make provision for loading because if we don't we'll have delivery drivers parking on the cycle tracks and footways.

The good news is that most businesses don't have deliveries made by 40 tonne articulated lorries and so making space at regular intervals allows delivery drivers to legitimately stop in a safe location and not have the stress of having to rush while they make their deliveries.

The loading bay above provides servicing space for an adjacent area which cannot be accessed by traffic during the day and a residential complex opposite. The cycle track is stepped in this case, so there is a dropped kerb with gentle ramp to get to the cycle track with a trolley and the forgiving kerbs are easy to roll over.

This loading bay is next to a carriageway level cycle track with a gap in the skinny protection island to allow the delivery driver to wheel his trolley over.

In some cases, there might be a space compromise if a street performs a vital motor traffic movement function and so with a loading bay in the main carriageway, then only allowing loading off peak might be appropriate rather than impacting on the space and time continuity of the cycle track.

One of the key things with providing loading space is that it should be considered as a higher priority than car parking. In fact, bus stops and loading bays are vital for the operation of our urban places and car parking less so (other than for disabled people who might need it). If there isn't space on the main road, then we could use a side street to provide a loading bay to keep the main road clear.

Of course, what is often forgotten is that building cycle tracks means that we can shift some deliveries to cargocycle. The beauty of this is that we can stop right outside the business and cut down on the time walking between loading bays and the front door. Cargocycles can also be taken right into the building as shown by Pedal Me below!