Author: Jeroen

In August 2024 Reading saw a significant change to its transport network. A lane for general traffic on London Road was converted into a bus lane. This caused a bit of a stir, with repeated claims that congestion at the newly introduced pinch point at the start of the bus lane (opposite Liverpool Road) would lead to increased air pollution.

As it happens, an air quality monitoring station is located right next to this supposed bottleneck, just inside Palmer Park. If you were to design an experiment to monitor the effect of the bus lane, you could hardly pick a better location to place a monitor.

The data from this station, as well as many other UK stations, is available from Defra’s website (or using the R package called openair). This means we can now have an in-depth look at the data and determine objectively what has happened at this site.

Air pollution and its causes

The station on London Road monitors PM₁₀ and NO_x concentrations. PM₁₀ stands for particulate matter with a diameter of 10 micrometres or less. These are small particles in the air that can pass into the upper airways. They are associated with respiratory disease and cardiovascular effects. NO_x stands for nitrogen oxides (NO and NO₂). Exposure to NO₂ is also linked to an increased risk of disease related mortality.

Both PM₁₀ and NO_x are generated in a wide range of human activity, including road transport, industry, energy production and domestic heating. Of the two measured pollutants, NO_x is most sensitive to road traffic, with around 65 per cent of the NO_x at the roadside originating from road transport.

We see this strong influence on London Road as well. The daily variations of NO_x show a low of just above 20 μg/m³ at night, shooting up to 50 and higher at peak rush hour.

A look at the data

So what does the data look like in detail? The below image shows the measurements for November 2024.

The data gives a very detailed picture, with hourly values of NO_x concentrations, wind speeds and air temperature. It is also clear that the data is noisy, showing a lot of variation. We therefore need to look at longer time periods (several months) to get a clear idea of any changes.

We also notice that the weather has a strong influence on pollution. For example, high wind speeds and warmer weather on the days before Nov 25 coincide with a sharp drop in pollution. This well-known influence of weather on air pollution muddies the water, making the influence of road transport less obvious. Is higher air pollution due to more traffic or due to a colder winter? Fortunately, we can use statistical models to estimate the influence of the weather and compensate for it. Here we have used a boosted regression tree approach, as implemented in the R package deweather.

Before and after

The bus lane was only introduced in August, so we’ll only consider the last four mounts of each year (September to December).

We see that, apart from a post-pandemic bounce-back in 2021, NO_x concentrations are steadily declining, likely due to cleaner engines, more electric vehicles and decreasing background concentrations (because of cleaner or reduced industrial activity). A similar trend occurs at other nearby monitoring stations and across the UK. For example, yearly NO_x concentrations at Oxford Road have dropped from around 80 μg/m³ in 2016 to 40 μg/m³ in 2024.

Most importantly, the graph shows absolutely no influence from the bus lane introduction in 2024.

It is possible that while air pollution has dropped at the bottleneck, congestion has extended onto the Sutton Seeds roundabout and thus caused air pollution to be more spread out. Google Maps traffic data certainly shows congestion there. It is, however, unclear to what extent this has changed since the bus lane was introduced. There certainly was heavy traffic there before as well (see the Reading Buses account on 𝕏 for past announcements of severe delays on the Orange routes). Reading Borough Council and Reading Buses should have more detailed traffic data on this, which we hope will be made public soon. It should also be noted that population density on the Wokingham side of London Road is a lot lower than on the Reading side and houses are further away from the road, reducing the health impacts of air pollution.

Conclusion

As in many important matters, it is difficult to gauge the impact of a change without good data. Humans are not very good at quantifying air pollution and are subject to all kinds of biases. Although more data would certainly be welcome, this investigation shows that, at least with respect to air quality, we’re certainly not seeing the catastrophic effects some had predicted.

While air quality in Reading is certainly improving, there’s still a lot of work to be done. Because of the strong impact on health, the World Health Organisation has produced air quality guidelines. Their recommendation is to keep yearly averaged NO₂ concentrations below 10 μg/m³, PM10 below 15 μg/m³. For 2024, all three roadside monitoring sites in Reading exceeded both thresholds, with the worst offender at Caversham Rd measuring 23.3 μg/m³ for NO₂ and 23.1 μg/m³ for PM₁₀.

The council should be applauded for their support for action on air quality: the Clean Air Living Matters and school streets programmes for local shools, improvements to sustainable and active travel, and increasing parking permit fees for more polluting cars.

However, more needs to be done to reduce the air pollution that is affecting the health and development of our children. Census data shows that in Reading more than half of commutes between 2km and 5km are done by car and almost one in three commutes of less than 2km. Many of these journeys could be walked or cycled, but more carrots (cycling infrastructure, reliable public transport) and sticks (road pricing, lower speed limits, blocking through-traffic) should be considered to reclaim our streets.

Finally, to get an idea of what air quality is like at your own home, have a look at addresspollution.org. Caution: the results may cause a desire for radical change. If so, please consider doing some of the following: talk to schools about CALM and school streets, organize a bike bus, respond to council consultations, write your councillors, and of course participate in Kidical Mass rides!

Kidical Mass rides are fun, a lot of fun! They are meant to be an opportunity for families to enjoy themselves. We ride our bikes, we chat, have some cake, and we play. But sometimes, we need to get serious as well. This is the campaigning side of Kidical Mass. We write articles on this blog setting out our opinions, we run petitions and we sit on council meetings about active travel.

We try to push the council to implement more infrastructure for safe active travel. A big part of this is enabling families to do the school run in an active way. For example, we have recently campaigned for infrastructure to connect to the new River Academy school.

It is great to see some of the measures the council is taking already. There is the Clean Air Living Matters (CALM) project to raise awareness about air pollution, including the role of motorised traffic. The council is also implementing wonderful School Streets to protect children near their schools.

Obviously, children don’t teleport to these school streets, though. There are still many barriers to active travel. I cycle to school with my child every morning along Hemdean Road in Caversham, a road with two primary schools and a nursery. Morning traffic can be hectic on this bendy road, with parents driving children to school, buses coming through and traffic using the road as a rat run. The available space is severely restricted by parked cars on both sides. After enduring numerous close passes on myself and my child, I have recently helped the school campaign for extra safety measures. While the council has sympathised with the requests, two arguments were repeatedly mentioned. If you follow discussions around active travel in Reading, you will surely recognise these recurring themes.

Parking space

Firstly, we are told, whatever we do, to not impact any parking spaces. Indeed, across the country it is often said that UK streets are too narrow for cycle paths and other infrastructure. This is clearly nonsense. Many roads are more than wide enough, but almost all of the space is allocated to the movement and storage of motor vehicles. This is a political choice, not a law of nature that can’t be changed.

This situation is only becoming worse with the trend for unnecessarily large cars, with almost a third of new cars sold being SUVs. These cars make the roads more dangerous for other road users by restricting space and visibility. In case of a crash, their weight and shape strongly increases the severity of the consequences. They cause more air pollution (including the electric ones). A recent study showed that air pollution caused by cars could have dropped by over 30% if this car obesity had not occurred.

The lack of space means there’s also no room for other much needed measures that enable active travel, such as shared cars and on-street bike hangars. It means no space for more plants and trees, which will be sorely needed to combat the urban heat island effect during heatwaves of ever increasing severity and to combat the dramatic decline of biodiversity. We have no space for benches for people to rest and socialise.

Crucially, it means no space for children to play. UK children are said to be among the least active worldwide. Is this any wonder? Have you had a look outside recently? Our society values the convenience of its adults to leave their belongings lying around over the health and safety of its children.

Reclaim

We need to reclaim our public space now, before the situation becomes even worse.

The council even supports this aim, in principle. The Reading Transport Strategy 2040 says the council will re-allocate space to active travel. The reality can, however, be very different. An example: the council has recently voted through the Bus Service Improvement Plan (BSIP). Interestingly, this plan included a short new section of cycle lane on Oxford Road. Sadly, even this short section is interrupted halfway though. By what you ask? Parking spaces, of course. Meanwhile, under the same plan extra parking spaces are created just around the corner. How is this re-allocating space for active travel?

So, there are vague claims, but no concrete plans for how to implement them. Other boroughs, are taking actions. Some are charging higher parking permit fees for larger, more polluting vehicles. Other councils have much more extensive parking permit zones. What will RBC do? It is not enough to have lofty aims without a plan for implementing them. The council can not be taken serious about its ambitions in active travel unless it sets out a clear plan for how to tackle this blight on our public space.

On some streets houses have no front garden where owners can park their vehicles, but many do have sufficient space. Parking a small vehicle on their own property is an option for many people, but most simple choose not to. Why would they if they are given extra space for free on the road? Let them convert part of their front garden if they really need to. If you look carefully, you will start to notice that some of those cars are almost permanently parked, sometimes with cobwebs on the tyres and a patch of dirt accumulated underneath the vehicle, even in front of houses with ample space, but owners can’t be bothered.

Money

The second oft-repeated argument is that their is no money for infrastructure. The council keeps a long list of requested changes to improve road safety that are awaiting funding. Many of these measures, no matter how small, will have to wait for many years for anything to happen. Yet at the same time the council is handing out huge subsidies to car owners by surrendering one of its prime assets: the public space. Most of this subsidy is going to owners of larger cars, often the wealthier residents of Reading. Meanwhile the poorest households often don’t own a car (30% of households across the UK don’t own a car) and miss out yet again.

Fixing it

Therefore, here are some of my personal suggestions to the council:

• Introduce size based parking permit fees,
• Significantly expand permit fee zones,
• Increase all parking permit fees to represent the true cost of public space. Exemptions and reductions can be given to those who can’t afford it.
• Set out a street-level plan and timeline for reducing parking space to make way for infrastructure for sustainable transport,
• Keep in mind the needs of disabled persons and use part of the freed up space to improve blue badge parking
• Increase space for shared cars and install bike hangars,
• Ring fence proceeds for active travel and public transport.

When will the council make clear that parking on our roads is a privilege, not a right? That children’s health, safety and future are more important than storing metal boxes?