20 mph sabotage at Leigh Woods

Our mid-august coverage of the 20 mph "firstbus" review, was illustrated with a photograph of a 20 mph sign nonchalantly keeling over.


That photo was taken on Bridge Road, the approach to the Clifton Suspension Bridge from North Somerset. If you are driving from Portishead down the 40 mph-limited A369, or sprinted down Beggar Bush Lane from Failand (60 mph), this is the first sign you are entering the Big City where you have to temper your expectations of speed with the need to share the road with people on foot and bike and keep your speed at around 20 mph.

Here's the sign today.

More specifically: it's where the sign was. Rather than repair the sign, someone in the "hypothesised" North Somerset Highways Maintenance Department has decided that rather than repair the sign, they'll just take it down and fill in the hole.

Which means, for anyone approaching Clifton on this road, there is no large roundel here warning of the speed change. There's one on the other side of the road, but it can be hidden by parked vehicles.
As a result: no major cues that you are in a 20 zone.

Does it change people's behaviour? Hard to tell.

Here's a rear-view clip from earlier in the week of one of tax-dodgers (expendable) approaching the bridge and going past where the sign used to be. They're doing 20-25 mph in the 30 mph zone.

If you look at the speed of the car WR07YFL coming up behind, it's probably doing 35-40. And, as they both cross where the sign used to be, the driver decides she doesn't want to slow down for a bike only doing 25 mph, and instead swing past. Which, given our tax dodger is positioned in the middle of the lane, and there's a lane separator fast approaching, isn't going to work. She eventually slows down and tucks in behind, only getting an option to go forwards when the cyclist pulls over on the "they don't have to pay any-more!" cyclist bypass of the toll gate. And then, the same cyclist pulls out in front and speeds up to 20 mph again, enough to stop the car from overtaking. We've documented dangerous passing on this bridge before; at least here the driver was sensible enough to not attempt it —but we wonder, if it had been an oncoming bike, not a car, would she have done any differently?

In town, she drives less aggressively; the cyclist is now "only" doing 20 mph, but so are the cars in front. Seemingly having the reason for the speed constraint being a car, not a bike winds up the driver less. Again though, we have to ask: if it hadn't been for that, would she have made another attempt?

Who knows? And one recorded incident doth not a defensible dataset make.

For now: if caught driving above the 20 mph limit, anywhere in the inner zone, just say "I came in over the Suspension Bridge and didn't see any signs!" Which, if it works, shows that all it takes is some laziness from an adjacent council for the whole 20 mph project to slowly fail.

Volvo bug reports, issue #1: MGIF driver

Given some of the Volvo self driving car developers are ex colleagues of Bristol Traffic team members, we get to file bug reports. Not some directly accessible issue tracker where you get to file stuff like "XC90 driver nearly killed me" only for tech support to close as a "works as intended", but at least get to give them cues about how their land-barges get used and abused in the field. Here's one of this week's Volvos. Mid-afternoon, not rush hour but within range of school pickup times. Sunny days to treasure before the miserable season settles in.

First: "MGIF" , "Must Get In Front"

Definition: A driver who is focused on overtaking the bike without looking ahead to consider "What happens next?

In AI terminology a "planning horizon of 1", usually loses to any computerised chess/draughts player with a horizon >= 2 unless the latter is awful about assessing the value of all enumerated moves & countermoves.

In this instance,

1. the speed limit of the bridge and the rest of the city for the subsequent 1-2+ miles in any direction is 20 mph. You can see one of the signs at 0:01 in the video
2. the cyclist she chooses to pass is doing 19-20 mph, still accelerating in their underresponsive steel-framed MTB.
3. The car a safe stopping distance in front is also doing 20 mph
4. And it'll have to slow down once it gets to the end of the bridge due to the road there (i.e it's 100% predictable, irrespective of time of day & pedestrian/traffic numbers)
5. the oncoming cyclist is going 15 + mph

Which means that

(a) there's no defensible reason to pass the cyclist "I need to break the law to overtake a bike cycling at the speed limit to get behind the other vehicle going at the same speed before I get into the city proper and really have to slow down".

(b) she's failed to anticipate how long it will take to overtake the bike, even as she speeds up to 25-30.

(c) the closure rate with the oncoming cyclist becomes about 40-45 mph. If the oncoming roadie hadn't been keeping to the far left of the lane, there'd have been a collision.

Looking back at the footage, she's hanging back at the split to two lanes at the tolls to make a late-binding choice of which one to go through -a slight sign of impatience.  She takes the left one; the right hand one is occupied by an SUV whose driver can barely see over the wheel, which is why the cyclist chose to hang back and wait: didn't seem safe to go ahead. As the Volvo comes through fairly rapidly, it's probable she has one of the contactless cards which you top up with prepaid bridge crossing tokens; sign of a regular user. Given time of day, perhaps a resident of N. Somerset doing a late pickup of a child from somewhere in Clifton, someone who cannot afford to be held up by any vehicle doing the speed limit.

Now, what is he dev team planning w.r.t. oncoming collision avoidance, where it assesses oncoming velocity of the approaching vehicle, adds with its own and estimates time-to-impact, so perhaps suggesting some alternate actions? And what to suggest? There's the "massively accelerate, swing in hard and then brake" strategy, which is an extension of this drivers decision (and essentially a reward), the alternative is: brake, swing behind the cyclist they tried to pass, put it off. Which is safer, but not generally that common amongst "legacy" manual-drivers. There's some psychological "we're committed now" decision which interferes with the more rational "braking to survive is a good idea" strategy.

enjoy

P.S. UK DVLA now gives MOT history over time: https://www.check-mot.service.gov.uk ...you can see that GP05RZE used to be a 3K/y child seat equipped barge of Hendon, NW London, then over to bristol to do 15K/y. Where you can see from the repeated warnings "pitted/scored disks, front headlamp deterioration" that the owner doesn't actually do any maintenance. Probably not a good sign. Almost as bad as a MkI Golf GTi with the wheels coming off..

The Psychology of Overtaking and VE08NXK

There is surprisingly little literature available online on the topic of The Psychology of Overtaking.

One paper you can find dates from 1997, Overtaking Road-accidents: Differences in Manoeuvre as a Function of Driver Age, by Clarke et al, of Nottingham University

Without going into the details, in particular questioning whether there's enough information on the general population of drivers and overtakers to reach conclusions about age, it does contain a good introductory summary of past work.

One quote in particular stands out

Wilson and Greensmith (1983) returned to the theme of the ‘‘inertial driver’’ in their multivariate analysis of drivers’ accident status in relation to observed driving patterns, gender and exposure. They report that accident-involved drivers drive more quickly ‘‘...and move around continually (especially overtaking) in traffic’’. The typical inertial driver differs from his high-exposure accident-free counterpart, in that he seems unwilling to change speeds in response to conditions by using gear changes, deceleration or braking.

This is interesting, as it does document a common behaviour you encounter on a bike: the driver willing to endanger themselves and others rather than tap on the brakes.

Here is a classic example on Belmont Hill, N. Somerset




Although it's a sharp bend, the gradient of the hill means that you can see oncoming traffic, especially when they have their lights on in the late afternoon. Look up to the top right of the picture and you can see a car coming down the hill. Bear in mind, it is still daylight, there may be an unlit vehicle or cyclist, and they would not be visible.

The presence of the car hasn't stopped the van VE08NXK from choosing to overtake precisely at the corner, going round the bend on completely the wrong side of the road. Either they hadn't looked or they didn't care. The driver coming down the hill was distinctly unhappy.

It would be really interesting to see what the reasoning of the driver was here. We cannot but suspect that it would be a "the cyclist forced me to make a dangerous overtake" claim, when really it was a "I was unwilling to adjust my speed in any way". Maybe we shall find out, having just reported them to A&S police as part of "Grass a Driver week".

Police Tactics

Good to see the Police are employing people to help discourage cycling in Bristol. Especially trying to discourage those travelling with children onboard their bicycle for the school run (as was the case in this video submitted by S via our East Bristol franchise). The TSD Fleet Support vehicle WX11EWN is a van that is registered as an Avon and Somerset Police Force vehicle and even shows up as part of proud collection of vehicles on Flickr if you Google "TSD Fleet Support Flickr".

Visit the videos Youtube page for full info at http://www.youtube.com/watch?v=EwpkhDdHOpY

Forward Planning

We've discussed before planning strategies, such as the MiniMax algorithm, and how a limiting factor is how far ahead you plan. The planning horizon limits your options, and often the game is won by whoever plans furthest ahead.

We are perfectly happy with a planning horizon of one: what is the next thing in your way. However, we are pretty unimpressed by this video which was sent to us of a car in Clifton who'se planning horizon was zero. When a car is coming towards you, you either do two things -commit at speed or back off. What you don't do is go alongside the bicycle at 15 mph with a car coming towards you at 20 mph, as that leads to an exchange of details and some insurance premiums, especially now that tax-dodgers are starting to carry cameras and no doubt willing to supply their videos as evidence.

If you are going to overtake with oncoming traffic, put your foot down!

Careful Passing

Everyone recommends giving bicycles room when passing, -and they complain when you don't, especially when traffic islands create pinch points.

Here a vehicle on Shaldon Road, Lockleaze, demonstrates the correct way to safely pass a slow-moving bicycle at a pinch point.

NC53BOV: "try your best"

Previously: Clifton. Today. Montpelier. We are going to show how the drivers in this part of the city not only know the width of their vehicles, but have far better situational awareness than other parts of the city. Look at this video here.



Some points.

1. The delivery van -whose way forward is blocked by roadworks- manages to reverse all the way back up the road to the next turning point. That is not something a normal driving test does, but it is hard. This person is skilled.
2. After getting past it, the non-road-tax-paying cameraman continues on their way.
3. Just as they are going past an expensive car, that car starts to pull forwards. We'd say pull out but in this road the pavement is about 1/3 of the actual roadway. That's why the driver of "NC53 BOV" didn't indicate; he wasn't pulling out.
4. The cyclist, who appears to be somewhat committed to the pass and exclaims "wait" and pulls past them. This is insensitive cycling and shows inadequate situational awareness.
5. The car driver isn't that happy with it, and after waiting a couple of seconds to get over the affront, sprints up fairly aggressively and puts some pressure on the bicycle to speed up. But he keeps his distance, there's nothing too threatening. Of course, driving half-on the pavement does limit your ability to put your foot down.
6. At the junction, the driver pulls up alongside and there is a polite discussion.

That's the difference between London and Bristol. In London: a fight. In Bristol a quiet exchange of views. The tax dodger explains that they are just trying to get to their destination alive. The driver of NC53BOV replies "try your best". The cyclist then congratulates them on their awareness of their surroundings and notes that they are more aware of them than the driver of CU54UWV. Then the troublemaker heads off towards St Werburghs.

After giving the tax dodger a chance to get ahead, the driver of the Audi RS6 Quattro shows that a key benefit of the automatic transmission and four wheel drive is the ability to put your foot down and have the car react, bringing you up to 40 mph in a 20mph zone in seconds. They manage to get safely past the cyclist before the oncoming traffic has a chance to get close, and, after making up for lost time, continue on the rat-run to the St Pauls Roundabout. Notice that despite his earlier unhappiness, he gives the bicycle plenty of room. This is someone who knows how to overtake safely, is aware of their surroundings, and able to adapt to them.

Safety in Numbers? More like tension

One theory is that as more people cycle, the more we, the important people, will expect bicycles. That's true, but it doesn't mean we welcome them. Instead it just makes us more frustrated.

Take this video of MJ06OSJ, going up Cotham Hill. They've been held up by a line of bicycles, and when they do finally a chance to overtake, there's another bicycle coming in the other directi0n. What to do?

As the video shows, the correct action is: continue anyway. If you've been held up by one bicyclist, you may as well punish another with a near death experience. It may discourage them from trying the same trick next time.

Where are the 20 mph zones they promised?

Someone posted us this video complaining that it shows a car driver unable to think ahead, because the driver overtook a bicycle aggressively on the way into Montpelier, whereas everyone knows that you only put your foot down on the way out. The tax-dodger not only ended up being held up by the Audi YY03YGM, they had to drop down Brook Hill, sprintg along Upper Cheltenham Place and then squeeze past the car on Picton Street blocking the road with the hazard lights on, while the Audi was still stuck on York Road negotiating rights of way with whatever was coming from the other direction.

We feel that the whole incident documents a more fundamental problem. The 20 mph zone isn't delivering what was promised.

The opening sequence shows how a bicycle doing 18 mph held up the car, but as soon as they go a little above 20 mph to get past them, there's another oncoming bicycle before the blind zig-zags. Even the bicycle video documents the other problems: the pedestrian and their dog on Brook Hill, the two bicycles on Upper Cheltenham Place, the two kids playing with a Pogo Stick in the road -our road- at 1:14, and then another bicycle. At least the car with the hazard lights on has paid for the right to be there.

Where are the 20 mph zones? The signs show them, but the car would have been lucky to have an average speed of 10 mph across the entire journey. We were promised 20 mph limits, yet it only takes one or two people walking, cycling or even pogo-sticking around and you brought screeching to a halt. We have been betrayed.

WX02UNH and critical sections

In computing a critical section is defined as something in which only one entity can have exclusive use of at at time, such as, say, a stretch of road or a single-lane railway track. The different bits of the system need to cooperate to gain access to these areas. One way of co-ordinating this access is the semaphore, a concept from the Dutch Computer scientist, Djikstra, based on the old railway notion of flag waving.

Of course, if a French or Italian person had come up with the idea, they'd have used a different name, like "l'indicateur", the car indicator. Because in these countries, to gain exclusive use of an overtaking area, you put your indicator on -way before you are ready to pull out. In the Alps, to put your indicator on before the turn has finished, before you can see if it is safe to pull out, tells everyone else that you intend to, that you have acquired exclusive use of the oncoming traffic lane.

This is why we have one little criticism of the Corsa WX02UNH on Pembroke Road.

We aren't going to criticise it for overtaking the bus on the wrong side of a traffic island. Yes, you aren't meant to do that, but if the anti-car council is going to conspire with Firstbus to put a bus stop in a traffic island, how else are you going to pass it.

Yes, it may be between 8 and 9 am, peak school run hours, but it is also peak commute hours, so the driver may be in a hurry.

No, what we are going to criticise them for is failing to indicate when they pulled out. They just assumed that nobody else was going to be aggressive and take the overtaking opportunity, when in fact any driver in front or behind could have -and because WX02UNH didn't indicate, they would have no warning that the other car was about to pull out. If two cars had collided while trying to drive the wrong side of a traffic island to overtake a bus -now that would be a complex one for the insurance company.

This is why our driving strategy is "Signal then commit". Your signalling is not a hint "I'd like to pull out", but a warning "Here I come", something people should see. But if you don't do such a signal, you don't help others to get out of your way.

Special Mention: KA05AFO

Today seems to be "cut up a bicycle day", and that's why reader "S" would like to send a big hello to the white van KA05AFO driven by a blonde haired woman along Cotham Road South at 17:00 today. Our reader says

"It takes a bold person to overtake a bicycle occupying the middle of the lane while doing 20 mph when there is an oncoming car, but you held your ground. You didn't think "I have a left turn shortly and there is no point doing this" - you recognised that the cyclist didn't deserve to be there, and had to be shown their place, regardless of any danger you yourself faced in the process.

As I looked over my shoulder to shout "WTF are you doing!" you had an expression of terror on your face as the car approached, and your diesel van didn't have the power to get round the bicycle. But you stuck to it, you committed to your action, and once you had started you would continue, regardless of how much mayhem or injury it caused. I hope the three seconds you saved from the action or the terror you experienced during it made it seem worthwhile.

Sadly, it won't be enough to make me give up commuting by bicycle, not just yet"

Well, there is the "yet" at the end, we can only hope that the other white van drivers in the city will contribute to making them change their mind. Meanwhile, can we note that this is the first email about a white van driven by a woman. We consider this a form of progress.