This smells of SUV bashing - why don't they make it linear with car CO2 or weight or road area or some physical measure.

The term "bashing" is inflammatory and is meant to discredit the person making the argument not the argument itself.

From what I see, the more CO2 a vehicle puts out, the greater the charge. How is that "SUV bashing"? There's SUVs like the Ford Escape which get better mileage (ie, put out less CO2 per unit of distance) than many small cars.

should not be penalised for the mayor's dislike of personal transport.

If you don't like your mayor, vote him out.

I agree with your sentiments Matt but maybe it's you that has the steering wheel on the wrong side.MahonJ, I don't think the mayor dislikes personal transport, London has been actively encouraging cycling as the best form of personal transport. I ride to work here in Melbourne, mostly along on-road cycle lanes, and love riding past the lines of stationary cars.

Cycling... even better! I'm in San Francisco, supposedly a liberal progressive place. & sure, we have a lot of bikers. But we also have piles of big ugly SUVs and loads of traffic. Cars sitting in gridlock. This, in a city that measures just 7 miles by 6 miles.

We do have a few hills... but there are plenty of flat routes.

Usually I'm there before my friends in their cars.

Excellent measure!
Ideally it's 7 tiers, 1 per band for more equality. Why should someone polluting 220g/km pay the same as someone polluting 40% less?

If someone decides to have 4 kids, they use more resources/pollute more - this external should be a real cost calculated in any household.

Clearly Kent has no comprehension of carbon cycles.

Indeed.

Just as a rough conversion for gasoline, 225gms CO2/km is equal to about 23 miles/(US)gallon, if I did the arithmetic right.

Sorry - screwed that up.

The second paragraph should read "For gasoline, 225 g/km..."

Theres a lot of car available to the the UK consumer that produce 120 g/km of less of CO2

cut and past
http://www.comcar.co.uk/newcar/companycar/poolresults/bandb.cfm

Too bad we don't get most of these here in the US.

Well at least we are starting to debate how we might deal with climate change.
It is however a global problem. It does not matter much if someone drives a prius if the chinese are building a new coal fired power station every week.
If it (GW) is real and lets assume it is; we have a huge problem requiring all the developed and developing nations to cooperate.
Unlike CFCs there is no obvious technical solution and it is not limited to a few devices - refrigeration systems and PCB manufacturing - it effects nearly everything we do.

The problem with London is road congenstion not CO2 levels. The most likely response to this is that even more people will buy diesels which won't improve the air quality but you make the rules and take the consequences.
What I was trying to say is that the tax should mirror the effect you are trying to achieve which is to make traffic flow more freely by reducing volumes. Hence make it a function of road space used by a vehicle. Mixing this up with CO2 levels seems like wolly thinking. Why should CO2 matter inside the congenstion are and not outside it ?
If you want to reduce CO2 you need a carbon tax for ALL vehicles. I would recommend a tax like the VRT tax we have here in Ireland. This is a purchase tax pait at the time of purchase. The Irish one is based on engine capacity (silly) and goes from 22 - 30%.
If they had one based on C02 levels (like Co2/km / 8) you would get a similar effect but targeted better.
Example: car generates 200 gms/km. Tax rate is 200/8 = 25% of purchaes price of car.

The advantage is that the tax is paid at the time of decision - once a car is bought the amount of CO2 it generates over its lifetime is more or less set. So the trick is to get people to buy low CO2 cars - and the way to do this is to make them pay the tax in advance.
If you tax fuel ( as most of europe does [ and well done ] ) you lack the "sticker shock" of the up front tax.
But it takes political willpower to bring in taxes like these. In Ireland we have no car manufacturers to lobby against such taxes - the US and China are different stories.

All I am saying is - congention is a local problem - CO2 levels in the atmosphere are a global problem - let's tackle each separately.

[ The solutions for congestion are simple and implementable: the solutions for GW are not simple and fiendishly difficult to implement. ]

Excellent!! Now if they can just get some additional capacity added to their subways. This is a good step in the right direction. Eventually, however, they just need to ban autos from the central core,perhaps with some exceptions for residents. I think they need to expand their mass transit infrastructure,however, before they do this.

Why not just ban the really big boys? My guess is that London could use the revenue. What is this revenue being used for, anyway?

We need to do this in the U.S. starting with New York.

t, by law, all revenue from the congestion charge has to go on improving London's transport facilities. Expanding the tube network is tricky and expensive. It's just too old and was never designed for the number of people it carries now.

It's the big city concept that's obsolete.

Clearly, since the world keeps urbanizing, as it has for several hundred years now.