The use of Liquefied Natural Gas (LNG) in transport is a suitable option to power large long-distance trucks in areas where gas is transported as liquefied natural gas because there are indigenous gas supplies and no gas network. The use of LNG in passenger cars is far less viable because on average passenger cars stand idle more often, which would give rise to high evaporative losses.

Employing regenerative braking in trains can lead to substantial CO₂ emission reductions, especially when applied to full stop service commuter trains (8 – 17%) and to very dense suburban network trains (~ 30%). Regenerative braking applied to freight trains can also lead to CO₂ emission reductions, albeit considerably lower than for full stop service trains (~5%). When regenerative braking is employed, the current in the electric motors is reversed, slowing down the train.

Improved air traffic management techniques like to avoid flying holding patterns, “green landings” and the use of relatively low speed airplanes for domestic aviation can reduce the emission of greenhouse gases substantially. Depending on their penetration up to 3% CO2 emission reduction can be achieved for green landings and 10-60% CO2 emission reduction for low speed airplanes. Moreover, these techniques will lower the NOx and soot emissions, thereby improving the air quality around the airport.

Fuel cells are used to produce electricity. They are considered a promising technology to replace conventional combustion engines in vehicles. Fuel cells may also replace batteries in portable electronic equipment. The most widely used types of fuel cells for mobile devices are Proton Exchange Membrane fuel cells (PEM FC) which are often used in vehicles, and Direct Methanol fuel cells, used in portable applications. PEM fuel cells use hydrogen or certain alcohols such as methanol as fuel.

An important way to reduce the greenhouse gas emissions that transport produces is to encourage and enable people to travel less. People travel less overall when they switch from private vehicles to public transport, walking or cycling, for reasons that will be explained. They travel less if their work is closer; if shops, health services and education are closer; and if family, friends and leisure activities are as well. They travel less if several purposes of travel can be covered in one trip, which is more likely if the places they need to visit are closer.

Public transport (mass transit) is critical to the proper functioning of any city, town or rural area. A range of transit modes offer different capacity opportunities, and therefore the potential for high or low impact on car use. Higher capacity systems cost more to put in, but offer much more potential reduction in total transport costs and greenhouse gas emissions. The social, economic and environmental costs of not having an efficient mass transit system never go away, so it is really a case of stemming these costs earlier or later.

The modal split for freight transport varies greatly by region, and is largely determined by geographical and economic factors. However there is a common trend towards more use of road transport, at the expense of rail and water transport. The latter modes have a substantially better environmental profile, but are limited by longer delivery times and the necessity of pre- and post-haulage by truck, i.e. inter-modal transport. In the logistic chain used nowadays, there are small local stocks and fast on demand delivery is required.

This article presents readers with the option of retaining three-wheeler taxis – with attention to better technology, maintenance and regulation – on the grounds that they perform a valuable role in the localities where they exist, and if they were removed the vehicles and travel practices that replaced them would produce increased congestion, road injuries and fatalities, air pollution and greenhouse gas (GHG) emissions. On these grounds, localities that do not have three-wheeler taxis might even consider introducing newer, cleaner-technology versions of them.

Non-motorised transport (NMT) is often a key element of successfully encouraging clean urban transport. It can be a very attractive mode of transport for relatively short distances, which make up the largest share of trips in cities. The key to reversing the trend towards more private vehicle use is making walking and cycling attractive, together with improving public transport. This can be done by a range of activities including construction of sidewalks and bike lanes, bike sharing programmes, urban planning and pedestrian-oriented development.

Road pricing is an effective economic instrument to reduce congestion, and to limit the growth in private vehicle travel demand. It has been successfully implemented in cities such as Singapore and London, resulting in substantial improvements in the urban environment and transport system. The largest barrier for ERP is public opposition by car users. However acceptance often increases after implementation. Important success factors are clear communication of the benefits to society and complementary policies regarding public transport and parking.