Earlier this year I worked on some charts and maps for a Greenpeace report authored by sustainable transport academic Robin Hickman, exploring the impacts of automobile dependence and the prospects for a post-car world. The report is online here.
The much debated phenomenon of ‘peak-car’ can be observed in many countries in the global north, in terms of a levelling off of private car use and increases in public transport, as shown in the graphs below. Many theories have been put forward to explain this trend, from the growth and densification of cities, to economic crises, fuel tax changes, to declining car use by younger demographics, and behavioural changes related to the internet. Given the many negative impacts of automobile dependence, from substantial GHG emissions, to air pollution, millions of road deaths annually, and contributions to the global obesity epidemic, clearly this behavioural trend is a great opportunity to develop more sustainable city forms much more widely across the globe.
This process is also observable at the level of individual cities, using data compiled by Newman and Kenworthy. Unfortunately this data is only available up to the year 2000.
The picture is of course different for newly industrialised countries, many of which are experiencing substantial growth in car ownership. I mapped data on vehicle sales, highlighting rapid growth in China and in Asia more generally, compared to static and declining markets in Europe and North America-
Thus the global sustainability challenge is to accelerate peak-car trends in the global north, and to try to curb the mistakes of automobile dependence being repeated in the developing world. Note that while the chart above suggests that the global south is increasingly responsible for GHG emissions, the picture from per-capita emissions is quite different as shown below, with the highest per-capita emissions in North America, the Middle East and Australia-
The current London mayor, Boris Johnson, has been slow to face up to the challenge. His tenure began by removing the western extension to the Congestion Charging Zone, thus increasing vehicle numbers in Inner West London, and opting out of using the Congestion Charge to tax the most polluting vehicles. This would have boosted the adoption of hybrid and electric vehicles (still only a meagre 1% of new cars) and reduced heavy emitters in Central London. Furthermore Johnson has not succeeded in comprehensively upgrading London’s bus and taxi fleet to hybrid and electric vehicles, instead embarking on an expensive new Routemaster project which still produces substantial emissions and currently makes up a minority of the overwhelmingly diesel bus fleet.
Looking to the future, London must now tackle the air pollution problem with a new mayor in the upcoming 2016 elections. The scope for change looks positive, as the main candidates on both the left and right have been openly discussing the need for change. What then could a new mayor do to address air quality and improve the health of Londoners?
Pricing Out Polluting Vehicles with the Ultra Low Emission Zone
To be fair to Boris Johnson, he did finally respond to pressure and announce a significant air pollution policy in 2013, dubbed the ‘Ultra-Low Emissions Zone‘. The ULEZ is set to come into effect in 2020 and essentially uses the Congestion Charging infrastructure to tackle the most polluting vehicles (similar to what Livingstone proposed way back in 2006). The question is whether the ULEZ goes far enough. It’s based on Euro emission standards, which measure NO2 and PM10/2.5 as well as CO2 emissions. It correctly targets diesel vehicles, requiring them to meet the Euro 6 standard, which only came into force in September 2015, so almost all current diesels on the road would have to change or pay the charge. This means that the main source of NO2 emissions will be appropriately targeted.
There are limitations however. The charge is only going to be £11.50 (except for large buses and HGVs), so it likely many diesel users will continue to drive into Central London and pay the charge. Furthermore the ULEZ will only affect Central London; the rules on diesel taxis and private hire vehicles have not been decided; and ULEZ zone residents get an overly generous exemption until 2023.
The next mayor will have a number of options that could be pursued if they want to be bolder than Johnson’s ULEZ proposal. These include increasing the ULEZ charge and/or Congestion Charge, bringing the ULEZ implementation forward to an earlier date, and potentially reintroducing the Congestion Charge Western Extension. All of these would make significant improvements to air quality, but would be controversial with drivers, many of whom were mis-sold diesel vehicles in the past as a supposedly environmentally benign option. The mayor may also want to re-examine the wider Low Emission Zone (LEZ) that tackles very polluting vehicles entering the whole of Greater London, as this affects the entire city and has not changed since 2012.
Banning Diesel? A more radical approach currently being proposed for Paris is to ban diesel cars all together. This would certainly make a huge improvement to air quality. The problem for London would be that the city’s bus and taxi fleet would fail this restriction, and there would likely be a backlash from thousands of car and van drivers. This would be a very confrontational approach for a new mayor.
The more pragmatic solution for London would be to work with the ULEZ framework, considering stricter measures and higher charges, and implementing the policy earlier. One very important issue for the new mayor is emerging from the current Volkswagen emissions scandal. It looks like the latest Euro 6 diesels produce significantly higher NO2 emissions in real world driving conditions compared to the misleading testing conditions. If this is the case then the proposed ULEZ will be much less effective in improving air quality (as Euro 6 diesels will be exempt from the charge). The ULEZ may have to charge all diesel vehicles, regardless of their Euro rating. This decision would need to made very early, so that there is sufficient time for car users to adjust behaviours accordingly.
Pedestrianising Streets and Upgrading the Bus Fleet Oxford Street is London’s busiest pedestrian street and has some of the worst NO2 pollution in Europe. A response that is gaining popularity is to pedestrianise the whole street. Certainly this would be an iconic change to both the image of London, and to the experience of the city for thousands of Londoners and tourists. The challenge for this measure is avoiding creating bus jams at either end of Oxford Street, and handling the extra demand levels that would be placed on the already congested Central Line. These challenges are not necessarily permanent however, as the arrival of Crossrail in 2018 (which follows the west to east Central Line route through Inner London) has been described as a ‘game changer’ that makes pedestrianising Oxford Street a realistic option. The new mayor should certainly pursue this possibility.
The wider challenge for the mayor is not to just think about Oxford Street, but to accelerate the upgrading of the entire bus and taxi fleet towards zero emission vehicles and develop wider pedestrianisation policies. This would improve air quality for all of London’s high streets. London is still at the trial stage of pure electric double-decker buses, which represents disappointingly slow progress considering how long we have known about air pollution problems. There’s been better progress on electric/hydrogen single-deckers. Considerable investment will be needed to upgrade the bus fleet, with decision-making based on real evidence and value-for-money. Johnson’s Routemaster project has failed both these criteria, and better leadership is now required.
Heathrow Third Runway All the main candidates for the London Mayor oppose the expansion of Heathrow, with air pollution alongside noise pollution amongst the most important factors. You can see how Heathrow already dramatically increases emissions in West London in the NO2 annual concentration map at the top of this article using the London Atmospheric Emissions Inventory data. This is due both to emissions for aircraft engines, and the thousands of cars driving to and from Heathrow everyday. The challenge will be how effectively the new mayor can challenge the UK government to reject the Heathrow expansion option.
Overall, the issue of air pollution has gained unprecedented prominence as we approach the 2016 mayoral elections. The main candidates need to respond accordingly in their manifesto commitments, with London having a lot of catching up to do after eight years of little change. It will be interesting to see which candidates are prepared to be bolder.
We know that knowledge networks and intensive competition within cities boosts innovation. There are also further scales to this dynamic. The networks and competition between cities at regional and global scales promotes the adoption of new ideas- as cities buy, borrow and adapt ideas from their competitors. It’s this latter global dynamic that we’re exploring in this post, investigating the spread of new ideas in a sector that’s intrinsically urban in nature- public transport. After widespread decline in the second half of the 20th century, transit has recently undergone an impressive renaissance linked to the dramatic growth of urban populations, high density forms and sustainability policies.
The spread of new ideas between cities is clustered in space and in time, as cities are strongly influenced by nearby competitors, as well as economic investment cycles. Therefore a natural way to visualise these spatial and temporal patterns is through animated cartography. This is the technique used here with the help of Processing and the MapThing library by Jon Reades (allows GIS data to be imported into Processing).
So first up we’re going to head back in time to the invention and dispersion of the underground/subway metro (data from metrobits.org; best viewed HD fullscreen)-
London celebrated 150 years of the Underground this year, and it was three decades after 1863 before other cities in Europe and North America had their own high-frequency high-capacity city centre networks. This delay can be linked to varied levels of industrialisation between countries, as well as the time taken to improve the metro concept with electrical power (the original Underground amazingly used steam locomotives). It’s interesting that the youthful American metropolises of Chicago and Boston were quicker off the mark to build metro systems than many European capitals.
Buenos Aires in 1913 and Tokyo in 1927 (now the world’s largest metro) were early exceptions to the European and North American monopoly on metro systems. Yet it took until the 1980’s onwards with the rise of Newly Industrialised Countries like Brazil, Russia, India, Mexico and Turkey for metro systems to become truly global. China is now in a league of its own with gigantic metros in Shanghai, Guangzhou, Beijing and Hong Kong.
Underground metros may seem like the best answer to cities’ transit demands, but they are highly expensive and disruptive to build, and are pricey to maintain also. These difficulties underlie another key innovation in the global rise of public transport- bus rapid transit. The use of segregated roads, specially designed stations and articulated buses enables BRT to have similar capacity and speed advantages of subways at a much lower cost. We can see from the animation that BRT begins as a Brazilian innovation (data from brtdata.org)-
Initially BRT adoption is highly clustered in Brazil’s major cities, with a few early adopters including Santiago de Chile, Quito, Pittsburgh and Essen in Germany. Then in the late 1990’s the dynamic changes with a burst of new systems in Central America, Canada, Australia, and mainly second-tier cities in Europe. Taipei has spearheaded the adoption of BRT into China, with many new large systems emerging. Sizeable BRTs also recently opened in Istanbul, Tehran and interestingly in Lagos where hopefully further investment in African cities will follow.
In our highly connected globalised world, new city innovations are likely to spread more quickly, and that seems to be the case with BRT. Indeed this acceleration effect is even more marked in the last innovation we’re going to investigate- the bike sharing phenomenon. Now bike share schemes are of course small investments compared to city-wide metro systems, yet they are still an interesting recent advance with similar global dispersion dynamics (data from Bike Sharing World Map and O’Brien Bike Share Map)-
The original pioneer of bike sharing is not as clean cut as the BRT and Underground examples as there have been several generations of innovation (see pdf article). In 1995 Copenhagen successfully created a reasonably sized (1,000 bikes) coin operated system with specially designed bicycles that tried to reduce theft. A small number of cities in Germany and France followed suit. The next generation began in Lyon in 2005 with a larger (4,000 bikes) system using smart card technology that greatly reduced theft. Subsequently bike sharing has exploded globally across Europe, North America, China and South Korea.
Paris has by far the largest system in Europe with 20,000 bikes. But even Paris’s Vélib’ is small compared to two huge Chinese systems in Wuhan (90,000 bikes) and Hangzhou (70,000 bikes). China’s strong cycling tradition has recently been in decline with rising car ownership, and hopefully the Bike Share boom will reverse this trend.
So to conclude, we are experiencing an age of truly global transit adoption with innovations spreading more rapidly through global city networks. While innovation has traditionally arisen in Western European and North American contexts, by far the greatest urban growth is in Newly Industrialised Countries, increasing demand for innovations like BRT. The rapid rise of bike share systems shows that relatively modest innovations can have a global impact when the innovation is popular and effectively implemented.
The ridership and scheme size data relates to current passenger levels rather than the size of the system at the time of construction. Would be great to do this visualisation with time-series ridership data, but this is not to my knowledge currently available.
The definition of metro and BRT systems used here comes from the database providers, and there is some ambiguity, e.g. in defining when a regional urban rail system can be classed as a metro (see metrobits.org).
Cities that achieve social and economic success without high car use generally have three things in common: high densities, good urban design, and successful planning frameworks that integrate land-use with public transport, walking and cycling networks. I’ve been working on an LSE Cities project that investigated two leading global cities in green transport- Copenhagen and Hong Kong- to better understand how their leading positions were reached. You can read the final Going Green report here.
The project required visualising the level of integration between public transport and urban density in these cities. We developed a technique where the rail network is shown as a transect through a 3D population density surface. This shows how the density of jobs and residents in these cities is clustered around major public transport nodes.
Copenhagen has a classic radial pattern, based on the famous ‘Finger Plan‘ developed over 60 years ago, where linear urban features are separated by thin green wedges. This is quite distinct to the UK greenbelt approach. Current expansion is focussed to the south of the city centre along the Orestad corridor served by the more recently developed metro links. This area sites the airport and transport links to Sweden, continuing the cross-border integration between Copenhagen and Malmö.
Hong Kong makes a very interesting comparison. It is on average 8 times(!) higher density than Copenhagen, and peak densities are around four times higher at nearly 150,000 jobs & residents per square kilometre. This is due firstly to the natural boundaries and country park designations that prevent suburban development, and secondly to the unique ‘Rail plus Property’ planning model run by the government and MTR, where extremely high development densities are pursued at rail station sites, and land value gains captured to fund public transport. The result is a polycentric pattern of jagged nodal development.
Another way to consider this relationship is to measure typical distances to rail & metro stations for these cities. As can be seen below, Copenhagen and Hong Kong compare favourably to other leading global cities like London and New York.
It would be interesting to pursue this analysis further for London. You can see that London scores relatively lower for the population within 500 metres of stations. Intensification policies at public transport nodes are a recent policy change for London. Accessibility figures are likely to change over time with several major intensification projects under way at rail stations in Inner London.
(Above figure based on metropolitan regions. Defined as Outer Met Area for London and 100 km by 100 km square centred on Manhattan for NYC).
Despite the litany of sins levelled at the automobile- it’s woeful energy efficiency, harmful pollution, congestion, road casualties, damage to public space, contribution to obesity- we are still wedded to the car. In the UK the car accounts for over three quarters of trip miles. The flexibility, security and door-to-door convenience of automobile travel remains a winning combination, particularly when we spent most of the 20th century developing car-based cities with limited alternatives.
Current planning practice restricts car travel to improve sustainability and urban quality of life. Short of an outright ban however, the car is here to stay in some form or other.
For the automobile to be in any way sustainable we need to radically challenge current systems of car design, driving and ownership to effectively create a new mode of transport. This post considers whether such a revolution is possible in light of exciting recent innovations.
We now for the first time have competitive alternatives to the internal combustion engine car on the market with electric and hybrid models from the world’s biggest manufacturers. These technologies dramatically reduce or remove tail-pipe emissions. Surely then the eco-car has now arrived and city transport has been saved?
Well… as electric cars (and vans/taxis/buses) become more widespread urban air quality should improve dramatically, as should vehicle mileages. But as we generate the majority of electricity using fossil fuels (and will continue to do so for the next 20 years+), CO2 emissions from electric cars remain significant.
Furthermore several other car design issues are not solved by electrification, such as energy used in manufacture, road congestion, safety and damage to public space. There’s a danger that electric cars become merely a green-wash cover for business as usual, rather than as a step towards bigger change.
Most cars are driven for a relatively short period each day, and are parked the rest of the time occupying land (around 10% in cities). On-street parking eats up large amounts of valuable public space from pedestrians, public transport and cyclists. It’s a wasteful situation, both for the efficiency of cities and for the environment due to the vast amounts of materials and energy used to manufacture our largely idle cars.
One increasingly popular solution in cities is car-sharing, with the largest company Zipcar now up to 700,000 members. Car-sharing is a convenient and affordable option for many city residents who want regular car access without the hassles of ownership. The popularity of smartphones provides an easy way to manage car-share booking. Comparable sharing trends are also evident for ride-sharing and for urban cycling.
Is sharing the answer then to the sustainable city travel? It’s definitely an important trend. Sharing allows a much better pricing model for driving, paying by the mile and charging more at peak times, thus encouraging more efficient behaviour.
Car-sharing coverage is limited however to denser urban areas, and it is not yet clear to what extent car-sharing can significantly reduce the total number of vehicles and car parking space in cities.
Self-Drive The last trend is at a much earlier stage than electrification and car-sharing, yet it could have the most far-reaching consequences. Sat-nav and parking-assist technologies were early steps towards greater automation in cars. Now Google as well as several manufactures have working prototypes of autonomous or self-driving vehicles.
Amazing yes, but what’s the point? In its current form, the application of this technology is not immediately clear, beyond providing a luxury car gizmo that lets you read the paper while your car drives you to work. But future developments will likely involve cars built around self-drive from the ground-up.
Potentially you could have a city taxi fleet of fully autonomous electric cars, requested by smartphone, operating 24 hours a day, moving to areas of high demand, charging batteries when not in use. Whilst bad news for taxi-drivers, such a system could be highly efficient and provide a quick and flexible complement to mass transit networks.
A related concept has already been developed in a rail-pod form operating at Heathrow airport. Dubbed Personal Rapid Transit, it is intended to combine the advantages of both private and public transport. Obviously the challenges of converting such a system to operate autonomously in the ‘wild’ of the urban environment are many, yet are increasingly being tackled.
If such a system could safely and legally operate, the implications would be massive. Imagine freight and courier services operating automatically at night to minimise disruption; your car picking up your shopping on its own, or taking a nap and waking up at your destination.
Reality Check It’s easy to get carried away with the wonders of new technology. Transport challenges require political and economic solutions as much as technological brilliance. Indeed relying on car manufacturers alone to green transport is as unlikely as “Beyond Petroleum” BP and Shell delivering the renewable energy revolution. Yet there is some incredible innovation currently emerging, and the next couple of decades are certain to be very interesting times for urban transport.
There have been some wonderful flow maps appearing online recently, such as Paul Butler’s global facebook friend’s map, and maps of global trade and flight patterns. Inspired by these, I’ve been mapping travel patterns in Great Britain using a similar “night-lights” visual style.
The above maps use data from the UK census connecting where people live to where they work, showing how transport flows form complex urban networks and extensive metropolitan regions. The data is at ward level, allowing a good level of detail:
Taking this visualisation further, a key issue for policy makers is how people travel, with private cars having greater energy, pollution and congestion impacts than alternatives. The final map below groups work trips into car, public transport and walking-cycling travel using an RGB colour scheme, creating a galactic effect (click for larger):
The aim of the visualisation is to put travel patterns in the context of the diverse urban scale and geography of Great Britain, and reveal the degree of regional variation.
The map really highlights how different London is in terms of its extensive regional public transport network, with the other major English conurbations like the West Midlands, Manchester and West Yorkshire being highly car dominant in comparison. The variation in public transport levels could be argued to relate to London’s massive size, yet the Scottish cities of Glasgow and Edinburgh perform well in public transport terms, despite being smaller than England’s northern cities.
Active travel modes of walking and cycling are generally minimal. The cities that do relatively well are the “cathedral cities” like Cambridge and York, with a few surprises like Hull.
The maps were created in ArcGIS using the XY to Line tool, then exported to Illustrator. A key aspect of such flow visualisations is that the thousands of overlapping flows add together to form denser links using a cumulative transparency effect. This is much easier to achieve using a vector graphics program such as Illustrator. Would be nice in a future post to add Northern Ireland and the Republic, and will get a data update with the 2011 census next year.
As cities expand with multiple centres spread over massive regional hinterlands, the need to better understand the geographical variation across and within cities has become more pressing. This need applies strongly to issues of travel sustainability, where urban centres differ greatly in the accessibility they facilitate for private, public and active transport.
Spatial indicators are a useful tool to summarise complicated intrametropolitan patterns, as illustrated in my new working paper mapping CO2 emissions from journey-to-work travel across the London Region. The results of this indicator show a massive range of travel emissions by workplace of up to 300%, with particular problems for airports and the specialised employment region of the Western Sector, as can be seen in the map above.
This paper was co-authored with Joan Serras at CASA, who helped with the development of the road and public transport network analysis to model realistic routing behaviour from origin and destination flows from the 2001 census. One interesting aspect to this was the inclusion of GPS data to model average road speeds in London as illustrated below:
Full paper abstract:
“This paper develops a methodology for estimating network distances and CO2 emissions for UK census ward-level journey-to-work interactions. Improvements are made on existing empirical measures by providing comprehensive intra-metropolitan analysis; increasing network routing accuracy with UK public transport timetable and GPS-based average road speed data; allowing multimodal travel; and developing metrics suitable for travel sustainability analysis. The output unit of CO2 emissions has been selected to enable the integration of mode-choice and travel distance data, and to aid compatibility with integrated assessment applications.
The methodology is applied to the case study of the London Region for the year 2001. A very high degree of intra-metropolitan variation is identified in the results. Employment sub-centres diverge in their per-capita CO2 emissions by up to 300%, with specific problems of carbon intensive commuting to major airports and the specialised employment region of the Western Sector. These findings indicate that subcentre travel variation may be intrinsic to polycentric urban structures. The paper discusses means to improve the methodology, in relation to issues of coefficient disaggregation and modelling more complicated multi-modal trips.”