We all like convenience. I understand the joy of stepping out of the house, getting into my own car, and just driving exactly where I want to go. But then there’s the traffic congestion. We can’t escape it; even the sleepy Somerset, UK, town where I live gets congested at rush hour and at school run times. But can this all be solved by road widening and building new roads? I know many people think so.  Our elected representatives are regularly asked to “sort the traffic problems out,” with the expectation of new roads or of widening an existing one. However, it’s not usually as simple as that.

If we have a pipe, but the flow of water through it is too great, then it seems a fairly simple matter to put in a bigger pipe to cope with the bigger flow. But people don’t behave like water molecules. Whenever a new road is opened, we change our behaviour: people take journeys they wouldn’t have made before or go by car instead of walking. They may move further out of town and thus need a car to make journeys they would have done on foot before. The result is that, within a few years, the traffic on the new road increases to fill the capacity available, the congestion returns, and sometimes the problem grows even worse than before.[1][2][3][4]

This ‘induced traffic’ effect was first observed way back in 1925 when the Great West Road at Brentford, London, was swamped soon after opening.[1] In the 1960’s, when the Blackwall Tunnel was built to double the road capacity of a Thames crossing in London, the traffic more than doubled in the first year after opening.[5] And in the USA, the Katy Freeway in Houston, Texas, was expanded to 23-26 lanes in 2004 – yet it still didn’t solve the traffic problems. Within a few years the congestion was worse than it had ever been.[6]

In “The impact of road Projects in England,” it says: “…the 54 road schemes that opened in the eight year period between 2002 and 2010, [resulted in] the equivalent of putting an extra 590,000 cars with average mileage and average emissions onto the road”.[3]

Here are other reasons that new roads are not necessarily a good solution.

New Roads Create More Air Pollution

Some people argue that building new or widening roads will reduce pollution, but in reality, because the congestion returns, the pollution increases too.[3]

We don’t normally notice the results of air pollution (nitrous oxide, particulates, etc.) as it has built up so gradually over the years, but, with the recent COVID-19 lockdowns, the effects have become very noticeable, with blue skies in cities around the world and the haze of pollution disappearing [7]. It has also been shown[8][9] that the death rates from respiratory diseases like COVID-19 are much lower in places with lower pollution levels.

This is quite apart from the significant effects of noise, light and even plastic pollution associated with new roads[2][3].

New Roads Discourage People from Cycling, Walking, or Taking Public Transport

If we think of travel in terms of natural human behaviour, if a road is badly congested, then some people will find another route or travel at another time, some will not travel at all, and others will think ‘blow this, I’m going by bike next time.’ This may be slightly more inconvenient for some – though it often is not once you try it. But if we build a new road (or widen it for cars), then the motive of avoiding the congestion is gone, and people are more likely to resort to the car.

New roads also tend to increase urban sprawl, encouraging homes and businesses to locate conveniently next to the new road, often in a place that’s far more difficult to get to by bike or bus and therefore requiring more people to take to their cars to get around.

New roads make us more dependent on our cars by increasing urban sprawl, often without bike or pedestrian lanes. Photos by Jared Murray and Avi Waxman on Unsplash

In fact, a study[10] has found that even when road space is removed from car use, say for pedestrianisation (yes, that’s a word!) schemes, it does not lead to a rise in congestion over the long term. Although there is a short adjustment period, the extra traffic quickly disappears as people find other ways to travel.

Very broadly speaking, the amount of traffic is governed by what is tolerable and convenient.

New Roads Cost Us More

New roads – and places to park cars, are incredibly expensive and time consuming to design and build, putting a huge stretch on limited budgets. They are also often controversial with residents, forcing people to move away. Additionally, they create a huge maintenance liability and often do not bring the economic benefits that were predicted when they were built.[1][2][3]

Further, we all know that walking or cycling to work keeps us fit and healthy, whereas sitting in a car leads to a deterioration in our health unless we make a real effort to keep active. Also, it’s often expected that new road schemes will reduce accident rates, but some actually increase accident rates due to increased speeds.[2] All this is leading to a greater strain on our national health services, quite apart from the unnecessary deaths caused directly by the extra air pollution.[11]

New Roads Create More Greenhouse Gasses

More traffic also creates more carbon dioxide (CO₂), another form of air pollution, but one we don’t see very easily. It’s creating a CO₂ blanket over our world and causing global warming. With road transport currently accounting for 49% of world oil final consumption,[12] almost 14% of global greenhouse gas (GHG) emissions were from road transport in 2010.[13] In the USA, makes up 29% of national emissions.[14] In the UK, it creates 28% of national emissions and 60% of this is from private cars – a figure that has hardly changed in the last three decades, despite advances in car efficiency.[15]  Further, a large amount of pollution (and GHGs) are also produced in constructing a new road.

Many of us are now concerned about climate change[16] and would like to reduce our GHG emissions. But building new roads, no matter whatever attempts we make to mitigate the effects, will end up increasing emissions.

Can Electric Cars Solve the Problems?

Electric vehicles (EVs) are definitely a part of the solution to reduce GHG emissions.[17] However, when EVs are made, CO₂ emissions are still produced, and the electricity used to power them often involves burning fossil fuels (think of the extra electricity needed to power all of those EV’s too).  Although no emissions are created when driving a car, the current lifetime emissions from producing and driving an electric car are only 30% less than a fossil fuel car in the UK.[18] Also, the lithium needed to make EV batteries is difficult to find and mining it is destructive to marine and tropical ecosystems.

If a person needs to buy a car then an EV makes sense. Solely switching to EVs won’t be enough, however, and they certainly won’t solve the congestion problems.  That solution should be reserved for people or trips where we cannot access public transport or cycle or walk.

Why Not Everyone Else?

We all like the supposed freedom of being able to go where we like in our cars. But have you ever noticed how car adverts always have wide open roads and use words like freedom, pleasure, progress… to make us feel that’s what the car provides? They don’t usually mention being stuck in congestion, problems finding parking or the full set of emissions that are involved in the life of the car.

But change is sometimes a challenge, and, we might think also, “that person/countries’ emissions are far worse than mine, they should tackle them first.”  To help us, consider the benefits we’ve discussed and that our actions don’t just affect us, here and now; they will affect our families for many years to come.

So, What’s the Answer?

If we wish to reduce pollution and GHG emissions, then we need to make better use of the road space that we already have. We need to travel smarter. The following photos show how much road space the same 60 people take up, using different modes of transport.

It’s a no brainer really, 60 people would fit into one bus, or they would fit in 60 cars that take up the whole street! Buses, trains, bikes and walking take up a fraction of the space that cars do and also emit a very small percentage of GHGs compared to cars.

That means you and I need to somehow make the shift to walking more or using bikes, e-bikes or public transport. We need to change our behaviour in order to protect this planet for our children. And we need to let our cities and regional governments know this is what we want. We can ask them to widen the roads to provide space for better bicycle facilities or even change a vehicle lane to a cycle or bus lane.

Switching to sustainable modes of transport will have significant benefits for our future. (clockwise from upper left) Tracy Samphier, Johan Shufiyan (Unsplash), Tracy Samphier, Roman Fox, and Kande Bonfim (Unsplash).

If we build more protected cycle routes and make our buses more frequent, convenient, and cost effective, then people will use them more.  Conversely, if we use our public transport more, the providers will be able to make the services more frequent and cost effective. But governments and local authorities likely will need to introduce measures to manage the traffic demand and GHGs. This will help stop other drivers from filling our streets with cars as we switch to greener modes.  It will be important to show support for government action in this direction.

A Vision for The Future

If we can make these shifts to greener ways of traveling, then this will lead to significant, measurable benefits in reduced air pollution, increased fitness, and health quite apart from avoiding the worst effects of climate change. We have had a glimpse of what this might look like with COVID-19 as more people are out running and cycling, enjoying the outdoor spaces and deserted streets.

So next time we are faced with a congested journey, perhaps think of badgering your elected representatives for better cycling, or nicer bus facilities, or better town planning to reduce the need to travel in general. You and many others will benefit in the longer run.

Tracy Samphier is a Chartered Civil Engineer with ten years of experience in highway design, including five years of designing road and bypass schemes.  However, a few years after the SACTRA report [1] came out, she decided to leave that discipline. After another five years assessing and repairing subsidence-damaged houses, she then moved to designing pedestrian and cycle facilities in the south west of the UK.  She now focuses on environmental work and her family. She also edits a blog at https://faiththegreenway.wordpress.com/

Additional Reading:

Interested in why it’s so hard to break the cycle of car dependence? This is a very revealing read:  The political economy of car dependence: https://www.sciencedirect.com/science/article/pii/S2214629620300633?via%3Dihub

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[1] SACTRA Report: The Standing Advisory Committee on Trunk Road Assessment report – original reference to Induced Traffic. December 1994 https://bettertransport.org.uk/sites/default/files/trunk-roads-traffic-report.pdf – When this report was released I was a young graduate engineer in a highways design department – it would change the shape of my career.

[2] Beyond Transport Infrastructure: Lessons for the future from recent road projects: Final report for CPRE and the Countryside Agency: by: Lilli Matson, Ian Taylor, Lynn Sloman and John Elliott. July 2006. And Supplementary Report 20/08/2006 http://www.transportforqualityoflife.com/u/files/Beyond-Transport-Infrastructure-fullreport%20July2006.pdf

[3] The Impact of Road Projects in England – Report for CPRE, Lynn Sloman, Lisa Hopkinson and Ian Taylor 2017 (available from CPRE’s website, www.cpre.org.uk)

[4] DfT: Latest evidence on induced travel demand. An evidence review. WSP. May 2018 https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/762976/latest-evidence-on-induced-travel-demand-an-evidence-review.pdf

[5] Campaign for Better Transport website: https://bettertransport.org.uk/roads-nowhere/induced-traffic (John Elliot’s slide presentation.)

[6] The Congestion Con: How more lanes and more money equals more traffic p24:  March 2020: Transportation for America. http://t4america.org/maps-tools/congestion-con/.

[7] ‘It’s Positively alpine!’ Disbelief in big cities as air pollution falls The Guardian Article 11 Apr 2020.

[8] https://www.nationalgeographic.com/science/2020/04/pollution-made-the-pandemic-worse-but-lockdowns-clean-the-sky/.

[9] https://www.theguardian.com/environment/2020/apr/20/air-pollution-may-be-key-contributor-to-covid-19-deaths-study.

[10] Reclaiming city streets for people. Chaos or quality of life? European Commission. Directorate General for the Environment. 2004. https://ec.europa.eu/environment/pubs/pdf/streets_people.pdf.

[11] Air Pollution causes 8.8 million extra early deaths per year. March 2019 https://www.sciencedaily.com/releases/2019/03/190312075933.htm.

[12] The Political Economy of Car Dependence https://www.sciencedirect.com/science/article/pii/S2214629620300633?via%3Dihub.

[13] IPCC Climate Change 2014: Synthesis Report.

[14] https://www.epa.gov/ghgemissions/sources-greenhouse-gas-emissions.

[15] UK Department for Transport – Decarbonising Transport Report – Setting the Challenge. 2020 https://www.gov.uk/government/publications/creating-the-transport-decarbonisation-plan.

[16] A median of 67% of people in 23 countries surveyed, said that climate change was a major threat https://www.pewresearch.org/fact-tank/2019/04/18/a-look-at-how-people-around-the-world-view-climate-change/.

[17] As per Project Drawdown, a scientific organization that studies the carbon life cycles of potential climate change solutions. https://drawdown.org/solutions/electric-cars. 

[18] Electric cars myth ‘busted’: https://www.bbc.co.uk/news/science-environment-51977625 Electric cars better for climate in 95% of the world. https://www.cam.ac.uk/research/news/electric-cars-better-for-climate-in-95-of-the-world.