With apologies to George Orwell, this seems like as good a way as any of summing up the current bien pensant view of private transport. Car journeys are to be discouraged, and public transport, particularly trains, should take precedence. It’s hard to argue that many people use their cars unnecessarily for short distances and that walking or cycling would both save them money and be good for their health. But for longer trips, most of us have to rely on some form of motorised transport. In that case, we should perhaps say the more wheels the better: buses, coaches and trains being the modes of transport planners and politicians would like to see us use more.
But there seems to be little real planning from first principles, simply a belief about what is right and what isn’t. At one time, the main concern was that road traffic caused congestion, delays and air pollution; now the main ostensible reason for opposition is emissions reduction policy. Cars are out of favour primarily because they produce more carbon dioxide per passenger mile.
At least, that’s the theory. It’s interesting to dig down and take a particular journey for comparison, let’s say London to Edinburgh. I have chosen this because it’s a good opportunity to compare three modes of transport: private cars, trains and aeroplanes, the latter in danger of becoming even more demonised than road transport.
For simplicity, consider a diesel-powered family car with two passengers going city centre to city centre, a journey of 404 miles via the M1 and M6. For a rated 140 grams of CO2 emitted per kilometre, this would equate to a total of 90 kg emitted. For two people, that’s 45 kg per person. At, say, 50 mpg, eight gallons of diesel would be needed, at a current cost of about £55: £27.50 per person. Total costs per mile would, of course, be higher, but the reality is that people do not consider other costs of car ownership when judging how to compare journeys. After all, car owners still have to bear these costs whether or not the car is used.
If, instead, this hypothetical couple decide to take the train, Transport Direct gives a figure of 34.7 kg of CO2 for the same journey. This is based on a Defra figure of 53.4 g of carbon dioxide per passenger kilometre for the train (for the two car passengers, the official figure is 70 g). As for the car, this figure will be directly dependent upon how many passengers are carried. But the cost is considerably higher. The ‘cheapest’ single fare on offer for travel on the day of writing was £120, for travel at lunchtime; for a peak time journey, this rose to £152. Booking a month ahead reduces this to £29, but with no flexibility to catch a train other than that booked.
As an aside, we should note the figures which Defra recommends be used for more local modes of public transport: London Underground is 74 g CO2 per passenger kilometre, and the figure rises to 134 g for bus journeys. Clearly, it would be impossible for bus or Tube journeys to be replaced by extra use of cars, but these figures suggest that urban public transport is merely a more practical way to get around rather than one which has intrinsically lower emissions.
The same London-Edinburgh journey can be made by plane. Booking an Easyjet flight at short notice – for today or tomorrow – would cost £155 (from Gatwick, Stansted or Luton), reducing to a more acceptable £40-50 for flights in the middle of next week. For booking several weeks ahead, the cost comes down to £20+, depending on time of day. Costs are broadly the same as for the train journey for the same booking period, although we shouldn’t forget that the railways, unlike airlines, need large public subsidies. Scheduled flight time is less than 1 ½ hours, but this is at least doubled by the need to arrive early for check-in and security. Air journeys, according to Defra’s figures, should be allotted a carbon dioxide emission of 171 g/passenger kilometre. For the London-Edinburgh journey, the Transport Direct website gives a figure of 111 kg carbon dioxide per passenger.
According to figures on the Transport Watch website, which also compares flights with high-speed rail (see fact sheet 5b), a Boeing 757-300 flying at 80% capacity generates 97 g CO2 per passenger kilometre. For an East Coast mainline train using grid electricity from a normal mix of sources, emissions amount to about 42 g/passenger km, which is about what I calculate for two people doing the journey by car. Clearly, the exact figures depend upon the assumptions made, and can only be estimates. But it seems that there is comparatively little to choose between the train or car for a journey of this length, although flying produces at least double the amount of carbon dioxide. On the other hand, if a person were to drive by him or herself, then emissions per kilometre would be quite similar to flying.
Like all such comparisons, the results will depend on how the boundaries are set. Transport Watch also refers to a paper by Chester and Horvath in Environmental Research Letters which argues that direct emissions during a journey are not the best way to make a comparison of environmental impact. Taking the entire lifecycle for vehicles and infrastructure, they suggest an additional emissions allowance has to be added: 63% for road vehicles, 31% for air travel and as much as 155% for rail. Taking these figures into account would produce a very different picture.
This rather simplistic analysis is not the whole picture, of course. It would hardly be practical to do a return London-Edinburgh trip in a day, for example, so an overnight stay would be needed. In most cases, this is also likely if travelling by train, unless you are lucky enough to live near a principal main line station. Flying can be the quickest, and allows a day return trip, but only if you live quite close to an airport. But in many cases the deciding factor is that a car journey can be done door-to-door. Flying or taking the train means some additional time and energy used to get to and from the airport or station. For most people, considerations of environmental impact – whether justified or not – are not usually the determining factor for mode of transport.
Finally, we shouldn’t forget that, although rising, carbon dioxide emissions from aircraft and trains are a small fraction of the total for road transport. Car manufacturers are continuing to make vehicles more efficient, with lower emissions, and road tax bands are increasingly making people more inclined to buy cars with smaller engines. But, to set against that, road travel continues to increase. Until a realistic alternative to the internal combustion engine can be developed and becomes the norm, the current situation will prevail. There simply isn’t the infrastructure – nor could there ever be – to replace a significant number of road journeys by rail, so the difference in overall environmental impact will continue to be small. For now, it seems, many wheels may be good, but four wheels are better.
The Scientific Alliance
St John’s Innovation Centre
Cowley Road
Cambridge
CB22 4LX
_______________________________