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How Green Is Public Transport?

Some motorists may be made to feel a little guilty when they choose to use their car rather than public transport. For many, however, the choice is not really much of a choice at all.

Some motorists may be made to feel a little guilty when they choose to use their car rather than public transport. For many, however, the choice is not really much of a choice at all. Some areas are not well served by public transport and parents sometimes have to drop off at such a variety of locations that any public transport that is available would simply not be a viable alternative. For many company car drivers, meanwhile, the number of destinations they visit in a working day would be impossible to achieve by public transport. 
Such arguments, however, do not stop the gnawing feeling that using the car is somehow less green than climbing aboard a bus or a train but calculating the comparative costs in terms of energy use is really not that simple. Transport is, of course, a major user of energy. It accounts for around 25% of greenhouse gas emissions so is obviously a major consideration in the fight against global warming. There is some good news in this area as the latest figures show that the energy consumed by transport in the UK is actually falling, albeit at the very modest rate of around 0.2% per annum. This figure, however, does not include aviation or shipping and both of those sectors are steadily growing
A study of transport trends over the past 20 years shows that the rate of growth in car use is actually slowing, causing some industry observers to consider that peak car use has actually passed. It is unclear why this should be so but factors like increased fuel prices, congestion, the attractiveness of public transport alternatives and green concerns could all be playing a part. The tax advantages of company cars have also been greatly reduced.
Rail passenger numbers, on the other hand, have doubled in the past 20 years and this rate of growth appears to be continuing. Commuters may be abandoning the car due to congestion but the rise in popularity in the use of smart devices may also be a factor. Many commuters are extending their working day by using such devices during their commute to email and carry out other work related activities. 
Railways are traditionally regarded as being very energy efficient but direct comparisons are difficult because of the number of factors involved. Passenger occupancy rates, fuel consumption and delays and congestion all contribute to a complicated picture. Nevertheless, it is widely accepted that trains are around 20 times more efficient than cars. That figure is not always reached, however. It is widely skewed by busy rush hour commuter routes and a mostly empty off peak train is sometimes less efficient than if every single passenger had driven instead. Because of safety rules, trains are also now heavier and the installation of features like accessible toilets has reduced passenger capacity. In comparison, cars have actually become much more fuel efficient and that trend is likely to continue.
Some conventional theories about energy use in transport are not always accurate. Electric cars, for example, are often trumpeted as having ‘zero emissions’ but the truth is not so green. In fact, only 15% or less of the electricity they use is generated by renewables. The other 85% is produced using fossil fuels. These cars simply move the pollution from the car to the power station. Hydrogen fuel cell cars also use much more energy than petrol driven vehicles to generate their hydrogen fuel.
Aircraft, too, have become much more energy efficient. Short air routes are undoubtedly large consumers of energy and such planes waste a huge proportion of their energy taxiing to and from the runway. A new Airbus 380, on the other hand, can get up to 70 mpg per passenger on longer routes, making it an extremely energy efficient mode of transport.
It is very likely that transport will continue to be one of our major users of energy but modern and fuel efficient cars are often a reasonably clean mode of transport and will continue to be part of that transport mix for many years to come.

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