Ultimate destination: building better roads

Air pollution is having a significant impact on human health. So how is it impacting us, and what can be done about it? Katie Haylor spoke with primary care expert Chris Griffiths from Queen Mary University of London, and Anneliese Allen-Norris from Environmental Defense Fund Europe...

Chris - Well pollution is a complex mixture of gases and particles. When people talk about air pollution at the moment they're generally thinking about traffic related pollution, although it's broader than that. The particles from for example burning wood and coal and so forth, others from diesel engines and internal combustion engines, gaseous pollution, a mixture of gases, nitrogen oxides, nitrogen dioxide, sulfur dioxide, ozone, carbon monoxide and so forth. These vary in concentration in the atmosphere depending on climate, wind, sources of pollution, and so forth.

Katie - So what is the evidence that links poor air quality to adverse health outcomes?

克里斯——主要来自流行病学研究so large observational studies. But it goes back a long way. Now the evidence is very strong across the life course, the Royal College of Physicians published a major report a couple of years ago showing that before a child is born, right the way through to old age, pollution is adversely affecting health. Whether it's the development of the child in the womb, development of conditions like asthma during early years, stunting of lung growth, stunting of brain development, to in older life incidence of heart attacks, strokes, dementia and of early death.

Katie - As Chris explains, it's not just the lungs that are affected by air pollution.

Chris - Pollutants which are inhaled, are absorbed and are able to travel around the body and have distant effects. So soot particles get lodged in cells from the immune system in the lining of the lungs and the greater the concentration of particles, the greater the adverse effects on the lung. But these particulates, particularly tiny particles, travel further so they've been detected in the bloodstream, brain and most recently in the placenta. The way in which they're adversely affecting health is not well understood, but it's likely to be a combination of deranging the immune system, causing long term inflammatory effects within the tissues, which will deliver the observed effect.

Katie - Now the exact mechanisms involved here aren't well understood and there are potential confounding factors which need teasing out, but scientists are concerned that air pollution could have life long and developmental impacts. So who is most at risk?

Chris - One of the important things is that poor air quality tends to be visited on disadvantaged populations more than advantaged populations. So the health effects tend to be unequally distributed across the population, so disadvantaged people tend to live in more congested, densely packed areas often closer to polluting roads and environments and so forth. So an important element of this whole drive to address air quality is to try to redress the health inequalities.

凯蒂-现在,我们有一些对世界的理解t air pollution is doing to our health, how much of this can be laid at the door of roads?

Anneliese - In London which is primarily where we're doing a lot of our scientific work with our Breathe London project, we know that the last lot of data, from 2016, the verified data, shows that around 50 percent of the nitrogen dioxide emissions come from transport, so mainly passenger transport - that is diesel cars primarily. So we know that it's a significant issue.

Katie - That's Anneliese Allen-Norris from the Environmental Defense Fund, an international charity who bring scientists, economists and lawyers together to tackle environmental issues.

pollut Anneliese——试图把这一列ion, that's a difficult thing to do. But it's one of the things that the work that we're doing with our Breathe London project is trying to address. The technology and the science is very complicated and it's also affected by weather. But there's very sophisticated modelling there that enables us to really tease out what these different sources of pollution are, if we know that we can put in place regulations that tackle those individual sources.

Katie - The Breathe London project that Anneliese mentioned there is a 12 month project involving partners from a variety of different organizations which aims to bolster the air quality monitoring infrastructure in London. The aim is to get a much better idea of air pollution exposure at a hyper-local level which can then better inform policymakers about the effectiveness of interventions designed to tackle air pollution.

Anneliese - London actually has a quite large network of reference grade monitors across the city, it's got around 100 in its main network which is one of the largest of most cities. However there's a lot of people in London and there's a lot of vulnerable populations in London, and there's not necessarily that hyper-local, empirical data in each of those locations. A lot of the gaps are often filled by modelling and obviously the more actual data that we can get, particularly in sensitive locations, schools for example around hospitals, that's really important. And that's kind of where we come in.

So Breathe London is multiplying the number of sensors in that network in London, combining what's already there with a whole new suite of sensors. We've got an extra 100 new, state of the art static sensors which measure various different pollutants. We've also got Google Street View cars which are jam packed of all of these sensors which are taking street by street measurements every few seconds across the city. We've also linked up with King's College and they have wearable sensors where schoolchildren and teachers are taking those sensors with them in backpacks on the way to school, so that you get a really local exposure measurement. We're making sure that this project is policy-relevant. A lot of our fixed monitors are deployed in schools so we're measuring pollution in areas where the most vulnerable populations spend their time, at the most polluted times of the day. We're also looking at different types of populations, so high and low deprivation areas and also really mixed areas in kind of major town centres and we're seeing differences in street by street level really.

Katie - For about a month now London has had a 24/7 ultra low emission zone within the central area of the city, where there is already a congestion charge. The ULEZ, as it's termed, ads on an additional twelve pound fifty a day for vehicles entering the zone which are not compliant. So older diesel and petrol vehicles. So how this extra charge made a difference to air quality?

Anneliese - It's only been in place for sort of a month or so and during that period of time we've had quite unusual days where the city centre might be cut off anyway. So we've had the Easter period where a lot of people would be on holiday. Also we've had Extinction rebellion and a lot of protests where the streets have been closed and the London Marathon. So we've only got a few days to look at and certainly the data that the mayor's office has provided suggests that there's far fewer vehicles which are the dirtiest vehicles entering the city centre. Now how that translates into meaningful pollution reductions is something that we're hoping to measure and we're keeping a close eye on that and we're hoping to be able to say more in a few months time about that.

Katie - Crucially, Breathe London started collecting data prior to the introduction of the ULEZ, so they should be able to compare pollution levels before and after the policy introduction.

Anneliese——关键的一件事是,我们是一个lso measuring carbon dioxide which is not what the current London network does. And that enables us to some extent to correct for the uncertainty that we do have around these meteorological effects and the impact of the weather on the pollution that we see. So we can really start to attribute where that pollution is coming from. So we should be able to better inform the mayor and citizens generally about the true impact of the ultra low emission zone and smaller interventions that might be happening around the same sort of time.

Katie - Chris Griffiths, who we heard from earlier, is also working on investigating the impact of the ultra low emission zone.

Chris - We're evaluating this by setting up cohorts of primary school children both in central London and in a neighbouring large town with relatively poor air quality, that's Luton. Actually in both those areas we're expecting improvements in air quality because the general trend will be towards an improvement. It's likely that there'll be a larger improvement in London and so we have two groups of children, one in whom there will probably be larger improvements in air quality if the ultra low emission zone delivers what it's supposed to do. Over the next year we'll be measuring the health of those children so we'll be trying to demonstrate whether improving air quality prevents the stunting of children's lung development. That's a primary aim of the study.

Katie - In the carrot and stick analogy, discouraging drivers from bringing dirtier vehicles into central London is arguably the stick. So are there any policy carrots when it comes to air pollution?

Anneliese - That plays on my mind a lot of the time. One of the things that the new data and more hyper-local data throughout the day can offer is better forecasting. So you can forecast for episodes of very high pollution and that could be used to restrict access even more stringently to certain areas whilst putting in policies, such as reducing the cost of transport for those particular days, so that you're giving people an alternative means of transport so they don't have to get in their car which might not comply with the restrictions. And we do see that happening in other cities such as Barcelona and Paris to an extent.

Being able to offer people an alternative means of transport through either shared transport or better access to bus services is something that's obviously necessary for people who don't have cars that comply. There's also very little being done in terms of incentivizing either citizens or businesses to transition to cleaner cars and vans. It's something that California has been doing for quite a while. The government could be putting in place market incentives that allow the industry to really progress so that the number of options for customers increases and is pushed forward onto the market, rather than continuing to incentivise people to purchase the dirtiest vehicles which is what we're seeing at the moment. And certainly things like an interest free loan which is what the Scottish Government did a couple of years ago, which is just finished now, which enabled people to actually get a new car which is an electric car, interest free with a loan. Those are the sort of policies that should be explored here, but we don't see much progress in terms of those sort of policies at the moment. It's something that's a real point of tension and it's something that the government needs to be addressing because if you're restricting access to the centre of a city, then you need to be able to offer to people means of transitioning to cleaner modes of transport.

How can we make roads safer? Katie Haylor spoke to transport engineering lecturer Richard Llewellyn from Edinburgh Napier University...

Richard - Some research was done many years ago looking at the causation factors behind collisions. One is that the road itself, how it's been designed, what the make-up of the road is, the way it's laid out. The second one is the vehicle itself, so how well it's maintained. And the final one is the user. What that research has shown is that 95% of all collisions happen because of user error, human error. So that really has been the focus of everything we do. And in trying to address that, historically we've had this approach called the three E's approach: one of education, getting the message across for good practice such as wearing seat belts, avoiding drink driving, and in more recent times avoiding things like use of mobile phones at the wheel.

其次是执行——这是那东西t obviously the police do, it's something that is essential but it's of limited effectiveness. If we didn't have the police enforcing road safety we may well have anarchy out there, but the more we have, it doesn't have a proportionate effect. And then finally the last one is engineering, which is changing the road environment and the vehicles on it. More recently we've moved towards something called the safe systems approach, which is looking at things holistically. It's looking at those three issues, but it's also looking at what everybody can contribute to them; so it's safe vehicles, safe use, safe speed, safe roadsides, and safe post crash care; looking at the whole story of how a collision happens. And ultimately what we're aiming for is Vision Zero, where no one is killed on our roads. And basically what we're taking in as a prime assumption here is that humans are fallible. We make mistakes, and that's that's really what we're trying to deal with: minimising the damage that can be done when a human makes a mistake.

Katie - One thing that occurs to me when we talk about driver behaviour: mobile phones. Most people know that you shouldn't be holding a mobile phone and talking in it when you're driving. But some people use their phones for GPS. Some people will have a bluetooth system or loudspeaker to have a work call or a personal call whilst they're driving. What's the evidence around that? Is that any safer?

Richard - Marginally safer, but the evidence would suggest that any form of distraction within the vehicle is going to take your attention off the road. Now you wouldn't have someone in a in a factory or a nuclear power plant, for example, operating machinery while they were talking on a phone; you'd want their full attention being given to that. And when you're driving a vehicle it's exactly the same thing. And in terms of the safe systems approach, for example in terms of mobile phone use, we're now looking at taking that sort of responsibility away from the driver, but also moving it on to companies. So many companies these days, for example, now have policies that if you are driving on business you are not permitted to use your phone under any circumstances. This contributes to the safe systems approach, it's not just one person's responsibility. We all have a part to play in this.

Katie - So how do you get - just for the sake of argument - to your destination, if you're using Google Maps on your on your smartphone?

Richard - Well I mean in terms of Google Maps and sat navs, the use of audio messages through that...I mean primarily it's the conversations, the thinking on the phone, certainly operating that sat nav, making sure that that sat nav is programmed before you start that journey, making sure that it’s hands free; and also things like, you know, you take regular breaks.

Katie - We live in an era that is ushering towards autonomous cars. We're not really there yet, but what we do see is increasing levels of autonomy in our vehicles. How much of that can we expect in the near future then, and is that going to make a difference to road safety?

理查德-最直接的行动being taken were outlined by the EU a couple of months ago. There was a political agreement in March of this year to add a couple of key things to vehicles that are produced and used in the European Union from 2022. And one of those is something called intelligent speed assistance. It works using a combination of GPS, cameras, radar technology to determine the position of the vehicle; and it compares that with a speed limit map. Now if the vehicle finds that you are driving in excess of the speed limit, there's a couple of options. It will either advise you you're doing so, or in ultimate circumstances it may even forcibly reduce your speed. Another measure coming about, and in fact is is fitted on quite a few vehicles already, is this concept of an emergency braking system. This is a system that detects objects such as a vehicle in the road ahead. And if you as the driver don't apply your brakes in time, these systems will automatically bring you to a stop. So these types of things have great potential to really make a difference in terms of the number of collisions on our roads. But there is also potentially a negative side with these things. In the rail and air industry, for example, we found when automation is taking place to vehicles, actually drivers’ attention or pilots’ attention starts to wander as the mind has less to do; that can create other problems. So it's not by any means perfect but hopefully a step in the right direction.

Katie - Is there another issue here in that these new cars that are coming in have these added safety features - that's great - but if the person behind me that goes into the back of me is in a really old model that isn't particularly autonomous, I guess there's still a risk there, is there?

Richard - And this is one of the big challenges I think over the next few decades of autonomous vehicles and how they're introduced, in a situation where an autonomous vehicle is completely free to do what it wants. We've got great technology: for example, Stanford University has just developed a race car that can be driven around a race track at speeds commensurate with that of a racing driver. It can deal with all sorts of conditions, wet conditions, and it's got really, really good detection systems. But you put that in a real environment where it's mixed with other vehicles, and indeed human beings making decisions on that road, and you start to have a problem.

高速公路在大多数情况下是合理的预测able, and I think in the future that's probably the first place that we will start to see autonomous vehicle use really starting to take off, perhaps we might see dedicated lanes to start with. When we move into the urban area things get incredibly complex. Humans are unpredictable. And going back to that fact that 95 percent of collisions are due to human error, those vehicles start having interactions, which really any amount of artificial intelligence is really going to struggle with. So dealing with pedestrians walking out into the road, interactions...I mean if you or I were at a junction and someone flashed our lights to let someone out, we'd know exactly what to do. But what would an autonomous vehicle do? And there's also a lot of other questions. A moral question: if an autonomous vehicle was in the situation where there were other vehicles and other users on the road, and it had to take evasive action, what does it do? And who would be legally responsible? And there's other issues like cybersecurity, people starting to hack into vehicles. So there's a lot of questions that we really need to grapple with in the future, and arguably these moral and legal questions are just as tricky as some of the technological ones.

How much time do you spend stuck in traffic - late for a meeting, or trying to get your kids home from school? You could be forgiven for thinking not much thought goes into controlling traffic in urban areas. But behind the scenes, highly complex systems are at work. Katie Haylor heard more from Edinburgh Napier University's transport engineering lecturer Richard Llewellyn...

Richard - If you take any big city within the UK, pretty much all of them these days will have something called an urban traffic control system, controlling all of the traffic signals within that city. Now traffic signal timings are set based on traffic flow. Historically we did that many years ago just manually and taking an average on a particular day, but these days it's much, much more high tech. So we've got detectors in the road and above the traffic signals they detect the flow at any one time and they adjust those green times that you see on a cycle by cycle basis. A traffic signal cycle is where we go from from red to amber to green and back again. And when you're driving in a city, if you're driving on on the main road into a city centre, what should be happening is you should be seeing some sort of linkage between those signals. So if you hit a green signal then as you get further down the street the timing should be such that your progression along that road is unimpeded.

Now unfortunately, it doesn't always work that way and it doesn’t always seem that way because lots of different things are happening on our streets. Buses are stopping, people at delivering goods, the flow doesn't quite work as well as it should do. But there is a lot of intelligence within those systems that make those changes to try to get the maximum amount of traffic through, and they can also do clever things as well like prioritize emergency vehicles, public transport, even respond to pollution. We have systems that can measure pollution and start to adjust the traffic patterns, adjust which streets get priority to try and maintain or reduce those pollution levels.

Katie - So I guess if you've got something like an organized parade and you've got days of notice, that's one thing. But if you've got an emergency services vehicle coming in you might only have a few minutes of notice so how quick are they at reacting, I guess, to the changing traffic conditions?

Richard - Well they can actually make changes to the signal timings on a cycle by cycle basis, so every time those lights change one amount of green time might be different from the next amount of green time. They tend to be more responsive in the off peak periods when things aren't as busy. The problem with the peak period is basically our networks are so congested there isn't a lot of slack, and the systems are very limited in terms of what they can do.

Katie - Considering that challenge, what is going on in the area of traffic control research to try and improve congestion, bottlenecks, or make journeys more reliable?

Richard - Yeah well I mean reliability that's the key word. People will tend to accept that congestion is a fact of life these days in cities. But what people find difficult to accept is that the journey time from day to day will change and they might allow 45 minutes to get to a meeting one day, and the next week it'll take them 90 minutes and this is a real problem to people.

One of the issues we've had historically is the ability to collect traffic data. We've been always reliant on roadside detectors or just traffic counts, but these days the number of people that are carrying around smartphones that are monitoring where they're travelling to how long it's taking is a great source of data. And companies like Google for example now are providing journey time information which allows traffic engineers to start to build a picture of journey time information and start to try to react to that and at least disseminate it to those that need to know. Ultimately though the problem still remains that that network is a finite resource and we really need to question who should be using it and when, that's really the big challenge.

Katie - Considering that vehicles are becoming increasingly more autonomous, is this set to impact upon how we control traffic on the roads?

Richard - Yeah, well, I mean autonomy brings with it some potential advantages in terms of driving style. It removes some of the unpredictability from the system. So if you imagine people driving along a motorway, one driver to the next, everyone leaves a little bit of a different gap between the vehicle and front. But if you have a machine in control of the distances between vehicles on, for example, a motorway, you've potentially got a much more stable flow there. There has actually been some suggestion that if we had fully autonomous vehicles the need for things like traffic signals could be completely removed from our cities, in that the vehicles themselves would communicate with each other and that we wouldn't need this technology by the side of the street. But that one's quite a long way off.

Katie - As you're a traffic expert I've got to ask, what is the best etiquette in terms of managing traffic flow if you come to a bit of a standstill on a motorway? You've got someone who's edging really close to you, someone who's trying to leave a bit of space and there's always that person who will go in the gap! Actually for efficient movement, what is the best way to behave in that situation, assuming you're not in an autonomous car?

Richard - A motorway works at its best when you've got a steady state flow. Now these shock waves and issues that occur on a motorway occur when there's been some event that's happened on the motorway. Now that can sometimes be something like an accident, but it can also be things like merging vehicles or someone changing lane or someone driving a little bit too close and braking. So if you want to adopt a good driving style and try to get the maximum benefit from motorways, the best way of driving is try to allow as much distance as possible from the vehicle in front, to brake very gently, within reason, and to accelerate away very smoothly. And by maintaining that smooth traffic flow, it might not completely prevent that type of congestion, but certainly it would go some way to help.

Katie - How do traffic control systems make sure that if there's a diversion, traffic is being sensibly and evenly distributed? Because I guess what you don't want is to think ‘OK, that route is cut off, let's send all of the cars in the city onto a different route and just cause a massive jam.’ How does that work?

Richard - Within traffic models, what the model will try to do is it uses something called the generalised cost of travel in terms of the vehicles on the network so tries to minimise the amount of delay within that network. So it will try many iterations to try to distribute that traffic as best as it can minimising that cost. And once it has found that solution that is the form of diversionary route that will be signed. Sometimes if we know of an event that's happening we might manually put something in and come up with a plan in advance but if it's in real time that's the way it would work.