Ex-Mayor Livingstone

Mayor’s buses not so green – check the facts

The Mayor published his London Climate Change Action Plan yesterday. It is all cheerily endorsed by Friends of the Earth, Greenpeace and the Green Party. It is mostly outside the Mayor’s competence too if he was honest.

There are some things the Mayor can control and he really should focus on these. The funniest graph in his document was this one:

Buses are pretty carbon hungry then

It seems if you jump in your car you often do so with other people, so average car occupancy in London is 1.6. This results in cars only pushing out 110 g/passenger kilometre compared to buses which push out only slightly less, 80 g/passenger kilometre. The figures show that cars are 37.5% worse than buses. The document points out that if there weren’t 1.6 people in each car then car emissions would be 60% higher. Yes, but they aren’t. The report does not point out in the same way that bus occupancy is 15 so if there was only one person in each bus then bus emissions would be 1400% higher.

Of course the Mayor is relying on journalists to only read the management summary of his document so the Evening Standard yesterday repeated this factoid from the management summary:

For the average Londoner, switching from driving to work to taking the bus will save 0.6 tonnes of carbon per year; taking up cycling instead would increase these savings to 1.1 tonnes.

This carefully phrased sentence inflates the carbon impact of cars by 60% above actual, delivered performance today by ignoring the extra 0.6 person in each car. When I saw the figure in the Evening Standard my first thought was that London’s buses are so empty that they are only 0.6 tonnes better than a car. The reality is that they are only 0.3 tonnes better. The Mayor is saying travel on my dirty, vandalised, wildly driven, inconvenient, stand-out-in-the-rain-waiting-at-a-bus-stop buses and save the planet.

One thing the Mayor can actually really do is to look at bus engine efficiency and occupancy. His action plan does not spell out what he will do to improve bus engines. His action plan does not spell out what he will do to improve London Buses’ low bus occupancy of 15, ie the average bus only has 15 people on it. Although the Mayor has no powers in this area the action plan does call for “support of car sharing to increase passenger occupancy”. The Mayor just wants to push out hot air rather than stick to what he can actually do.

6 replies on “Mayor’s buses not so green – check the facts”

The devil is in the detail and the detail is not published. The figures assume a car using 176g per km (cars use anywhere between 100-400g/km) and a bus using about 1200g/km. Figures for buses are not readily available but quotes the Volvo B7TL Double Decker at 1,406g/km and Mercedes Citaro Arctic (so called bendy bus) at 1585.7g/km. So what type of bus has been used for the comparison? Looks like it’s probably a small one. And if there are only 15 people on a bendy bus that’s 100g/km each; they be more environmentally friendly if they shared 8 cars between them! Aren’t statistics wonderful?

How do they get the tram/light rail figure of 50g/km?

Looks like buses are the better environmental option at peak times (where passenger numbers will be much higher than average), but off-peak cars may well be better, especially if the car driver gives someone a lift.


Vlod Many thanks for your clarification. Various figures have been bandied about; the more elderely ones in “killerjewels”. Those published in Inst of Elect Eng Review were different to ones I’d seen published at the Alternative Technology centre in M in Wales. My mate made a Freedom of info Act request from TfL recently and was told the same figure for the car but 56 and not 50 for the tube. And where did they get the 50/56 figure for the tram/light railway? I have to assume they are the same thing same old electrical generation losses same variable distances between stops same problematic consumption figs when half full. What is really interesting is that these energy figures are “out” now and we will all have to look at the consequences of transport policy decisions more carefully. If a car has passengers in it it could be greener than all forms of public transport. Excluding car driving commuters and their passengers who come to work in Ealing by installing universal exclusion zones (CPZs) might be considered environmentally unfriendly. The crude CPZ policy the present Council inherited from the Labour Group now needs urgent review on the basis of this data. This requires no small amount of care, science, logic and debate all of which is difficult when the till bell (equivalent to income generation) rings so loudly.


I note that trams come out pretty well in this…so why is the Ealing Conservative Council so against them?



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