Martin Hodgson examines the environmental impacts of the UK’s ageing transport infrastructure and asks how modern transport policies can create an infrastructure that can lead to a more sustainable future.

Effective transport systems that serve the needs of the population are a vital part of any successful modern society and economy.

However, all transport systems have an environmental impact and this is increasing alongside the demand for ever more mobility. The UK supports an ageing transport infrastructure, particularly in its rail and road networks, that struggles to cope with this demand. Investment and new technologies are desperately needed.

The current environmental impact of transport

Sustained economic and population growth throughout Europe in recent decades has stimulated increased car ownership and increasing demands for people to get around, both for work and pleasure. A growing population and the expansion of new markets mean more goods and materials to be transported. The air industry also looks to expand to cope with holiday and business demand, with plans in place for more airports and runways.

Transport systems are major emitters of greenhouse gases, contributing to global warming and air pollution levels worldwide. About 95% of transport use is fuelled by the petroleum industry, and car use alone is estimated to be responsible for 20–25% of global carbon dioxide (CO2) emissions.

Road use is the dominant transport mode for all longer journeys in economically developed countries, and this has a significant effect on air quality, particularly in urban areas. The UK alone has more than 34 million vehicles on its roads, 28 million of those are cars.

Air pollutants from vehicles include nitrogen oxides, carbon monoxide, hydrocarbons and particles. All have a damaging impact on human health (contributing to lung disease, heart attacks and asthma), especially for those living in town centres and alongside busy roads.

Cleaner fuels and more efficient car engines, as well as emissions checks that take older cars off the roads, have helped to improve UK air quality in general in recent years but many areas still fail to meet European limits.

This, campaigners argue, is partly down to the use of diesel cars. Diesel cars have been billed as “green” by governments and environmental groups because they are more fuel efficient and emit less CO2 than petrol. However, diesel fumes are significantly more damaging to health than those from petrol engines and contribute far more to air pollution. The future is likely to include higher taxes on diesel vehicles or even their being banned from city centres.

In an ageing road network such as that in the UK, utilised to the limits of its capacity and with significant daily traffic flows, congestion is another factor that makes environmental impact worse. Congestion reduces fuel efficiency and raises pollution and gas emission levels.

Noise pollution is another significant environmental impact of traditional transport systems. It is estimated that noise from road traffic negatively affects more than a quarter of UK residents. Vehicles have been subject to noise standards for many years through EU legislation but tyre and engine noise continue to be a major problem associated with the high volumes of cars and other vehicles on UK roads.

However, it is not only the environmental cost and level of pollution from the use of motor vehicles, trains and planes that needs to be considered with regard to sustainability. The infrastructure that supports transport also comes at environmental cost when the impacts of road and rail building and maintenance are taken into consideration. Such impacts should be seen not only in relation to energy consumption and pollution, but also in terms of impact on countryside and communities, as ongoing public opposition campaigns over new transport routes and airport runways demonstrate.

The building and disposal of motor vehicles is yet another factor to add to any assessment of environmental cost. It is estimated that for a standard motor vehicle during its lifetime:

  • 10% of the CO2 emissions associated with it come from its manufacture

  • 85% come from running the vehicle

  • 5% relate to its disposal.

Vehicle waste is a significant issue in itself, with the requirement increasingly being for parts and materials to be recycled and for sustainable waste options.

Recent years have also seen increasing pressure for the infrastructure behind motor vehicle manufacturing to change and for companies to use newer and greener methods of production based on sustainable procurement throughout their complex transport supply chains.

Sustainable transport policy

The environmental sustainability of transport has long been a major factor in UK government policy and in European legislation.

In addition to the pollution caused by transport systems today, projections of the need for more transport capacity in the future mean that politicians and planners have a complex set of factors to take into consideration. For example, with congestion already a problem on overcrowded roads, the pressure for new road building and road widening projects is considerable. However, if vehicle use rises without an increase in infrastructure capacity, congestion will be an increasing problem.

The balance of transport models is a delicate one. Road transport, rail, air and sea transport all consume energy and create pollution but present different patterns of energy use and efficiency for different types of journey. Successive governments over the past 50 years have sought to balance these options in the most environmentally sustainable way while at the same time encouraging the uptake of energy efficient new technologies that pollute less and have less environmental impact.

This is a difficult balance to achieve, especially without large amounts of money to use in building new energy efficient infrastructure.

In recent years the tendency for national governments has therefore been to use factors such as fuel cost and car taxation as levers for change while at the same time encouraging vehicle manufacturers and transport providers to adopt new energy efficient technologies. Local and city authorities, on the other hand, in co-operation with employers, have tended to concentrate on establishing more sustainable local networks based on public transport options and the needs of businesses and communities.

It has long been recognised that different communities need different solutions. This is particularly the case in urban and rural environments where transport is important for social inclusion. Local authorities should work together to develop the infrastructure necessary to support sustainable development, supported by greener local transport assessments and plans.

Local policies on public transport and parking, for instance, will have a powerful influence on people’s choice of transport option. Even the simple fact of making public transport information faster and easier to find (journey planner apps or increasing digital signage for buses, for example), may help influence people to choose public transport.

Organisational policies

Organisations and businesses, both private and public sector – and particularly the larger ones - also have an important role to play in sustainable transport planning.

In many areas the flow of people to and from work, particularly at peak times, represents a major transport issue where the capacity of both road and rail networks is often stretched to the limit, impacting both on congestion and on the quality of local life. Businesses are beginning to address this with flexible working hours and home working options, to even out the flow of employees.

In many areas large businesses work closely with their local authorities to address such transport issues in their communities. For example, London is looking at retiming freight deliveries outside peak commuter or shopping hours. Encouraging staff to use greener cars or to use public transport or to walk or cycle to work is a common approach in companies that, for example, offer tax-free schemes to encourage employees to buy bicycles for their commute as part of a sustainability and well-being policy. With increasing pressure on limited parking resources in many areas, these types of approaches should be co-ordinated with local public transport options and plans.

Investment in greener car lease fleets and delivery and haulage fleets is another method of increasing the sustainability of businesses.

In addition, businesses can reduce their reliance on expensive transport requirements by investing in new telecommunications technologies. Rather than requiring staff to travel to attend meetings, many modern businesses use techniques such as video conferencing. Modern systems using sophisticated smartscreen technology can enable people to run virtual presentations, meetings, training and webinars, all at a fraction of the cost of a traditional face-to-face event.

Public transport and cities

Well-used public transport road systems, even those using traditional diesel vehicles, are more sustainable than private vehicles, using less road space and fuel than the number of private vehicles needed to transport the same number of people. Green public transport vehicles including electric trains, trams and buses are more efficient still.

The pressures of congestion are particularly acute in cities, where the majority of people live and work. Adequate investment in so-called "urban mobility" plans are vital if cities are to avoid the blight of congestion and poor air quality caused by too many cars. Plans should focus on clean, sustainable public transport provision and, critically, car-free areas, making walking and cycling safe and healthy alternatives.

Public transport companies are looking closely at ways to build sustainability, reduce pollution and minimise energy use. Tube trains now use regenerative braking found in hybrid and electric cars, where the kinetic energy of the vehicle is captured and converted into electricity (used to recharge the battery in cars). Transport for London claims that regenerative braking saves up to 25% of the energy used by the train.

Milton Keynes has been testing induction charging for electric buses since 2014. This is a system whereby the bus tops up its batteries wirelessly whenever it stops to pick up passengers by driving over a charging plate in the road. The town is now running a five-year test to see whether its eight electric buses can perform on a par with their diesel counterparts in a real world operational environment.

Interestingly, the electric buses are so quiet that they are looking to add noise to the vehicle for people with limited sight!

Fuel efficient cars and vehicles

Fuel efficient cars and vehicles are making up a growing percentage of the European car market and the UK Government has introduced financial measures to favour cars with lower CO2 emissions. The EU has also set a mandatory CO2 target for car manufacturers, which aims for a 40% reduction in emissions by 2021. As a result, new car tail pipe emissions show an all-time low, representing a 24% reduction since 2007.

Hybrid vehicles use an internal combustion engine combined with an electric engine to achieve better fuel efficiency than a regular engine. Natural gas and biofuels can be used as an alternative and more efficient transport fuel to petrol.

Electric cars, however, are seen by many as the car of the future and are being actively encouraged by the Government through tax breaks, grants and, in London, exemption from the Congestion Charge. They are increasing in popularity with many vehicle manufacturers now producing electric variants powered by batteries and recharged by being plugged in at recharge points. Such vehicles are quieter and create fewer emissions than standard engines.

Although the design and technology in electric cars has improved in recent years (sales increased fourfold from 2013 to 15,500 in 2014) they have so far suffered from limitations in size and range. Most electric variants are small cars and are limited in the distance they can travel before recharging (under 100 miles a day). However, it looks certain that this is being resolved with more efficient batteries and chargers that work more quickly and efficiently. The induction charging system described above, where cars can be charged wirelessly from embedded plates or cables in the road, is also being explored, and would reduce the need to stop at a charging station.

At present you need access to a garage, drive or off-street parking in order to recharge the electric car overnight. However, Government funding allows householders to apply to the local authority for a public on-street charge point close to where they live. Government grants have also subsidised the purchase of eligible cars and vans by up to 35% of their cost for both private vehicles and fleets.

Despite these improvements, the environmental sustainability of electric cars must be assessed throughout their whole lifecycle, not just their running costs. Their manufacture, maintenance and disposal must be considered, as well as the variable electricity costs where they are operated.

Fleets of electric vehicles may present an alternative option for the future sustainability of the motor vehicle, but the option is not such an effective one if they are fuelled by electricity from non-renewable sources such as gas, coal and oil. Increased electric car use must therefore be linked to greener energy policies and renewable power sources in a truly sustainable transport system. And a comprehensive recharging network across the UK must be developed.

In practice, although greener vehicles are a more sustainable option than petrol or diesel vehicles, they all still have some environmental cost and, of course, still contribute to road congestion.

The movement towards greener vehicles is encouraged by the government through road transport policy. The vehicle licence system is used to reward drivers of more fuel efficient vehicles with lower rates of tax. Petrol and diesel tax and subsidy is designed to do the same thing, trying to balance costs so that motorists and businesses can afford to run their vehicles, but at the same time dissuading wasteful use of transport and encouraging fuel-efficiency.

Intelligent roads

As well as changes in motor vehicles, new technologies and more efficient road infrastructure are also playing their part in improving sustainability.

For instance, "Smart Highway" concepts, originally developed in the Netherlands, are finding many advocates in the UK who want road planning in the future to include such things as:

  • electric vehicle priority lanes, which not only encourage the uptake of such vehicles but also include induction charging systems to charge their batteries as they drive

  • dynamic lanes which can be changed through a management centre to control speeds and traffic direction, improving capacity management and hence fuel efficiency

  • interactive lighting controlled by sensors which register when a car is approaching

  • glow-in-the-dark paints and surfaces which absorb light during the day and release it at night - thus making roads better lit without lighting

  • quiet surfaces to reduce road noise.

Other developments in the USA look certain to be imported to Europe in the future. These include the Solar Highway, an intelligent road that provides clean renewable energy through in-built solar panels. The panels not only power roadside lighting and other "smart" features, but can also power electric vehicles through induction, export excess power and create capacity for data delivery.

Microprocessors in the solar panels allow cars and vehicles to be tracked, potentially across entire road networks, boosting security, combating crime and monitoring speeds and road use. Such monitoring can also help with congestion, warning cars of road conditions ahead, interacting with onboard GPS systems and advising on alternative routes.

In the USA the Solar Highway concept is not only being seen as a solution for some of the environmental costs of road building, but also as potential solution to the prohibitive financial costs as well. In effect the road pays for itself through power generation.

Last reviewed 27 July 2015