LONDON — The Hackings, like many of their neighbors, are a two-car family. Every morning, Giles Hacking gets into his Mercedes CL500 in West Kensington and drives to his office across town near London Bridge.
Sarah Hacking piles the three children into the Jeep Cherokee and drops them off at their schools. Often, her mother pitches in and delivers one of the youngsters.
Soon, though, multi-car families like the Hackings may be wishing all they had to contend with was London's $8-a-gallon gasoline. In an unusual municipal experiment aimed at fighting global warming where the rubber meets the road, the British capital in October is to begin imposing a $50-a-day carbon emissions fee on every gas-guzzling private vehicle driven in the central city.
Even for the Hackings, who live in one of London's better neighborhoods and earn a good income from an old family import/export business, that will be a significant jolt: $100 a day for the school and work runs, $150 if Grandma gets involved.
"It's outrageous," said Sarah Hacking, expressing a sentiment that appears to elicit a strong amen from many of those here who drive the big sport utility vehicles that Mayor Ken Livingstone refers to derisively as "Chelsea tractors."
"We'd have a massive loss if we tried to sell our cars. And I can't have a tiny little car because I have three children who go to three different schools," she said.
"At the moment, we just have to pay. We really have no choice."
The new fee, adopted by the mayor after a long consultation with the public, has prompted threats of a lawsuit from Porsche and anger from many London drivers, some of whom have vowed to make it a central issue in the campaign leading to the mayoral election May 1.
For five years, London has been assessing drivers a daily "congestion charge," now set at $16, to drive into the central city and a large swath around it, a fee designed to tackle the infernal bottlenecks that have turned much of London into a parking lot.
The program has become a test case for major cities around the world. The New York City Council this week voted for a three-year trial program that would impose an $8 charge on vehicles entering Midtown and Lower Manhattan, a plan that still needs approval from the state Legislature.
San Francisco has studied imposing a charge as a way of easing central-city traffic jams; cities in Norway and Sweden have also flirted with congestion pricing; and Singapore has been charging downtown drivers since 1975.
But London's pending carbon dioxide emissions charge goes beyond traffic control and establishes one of the first significant municipal climate change programs in the world.
It is designed to lure -- some would say shock -- Londoners out of their big Porsches, V6 Mondeos and 4x4s and into respectable Priuses or Renault Clios.
Drivers of the lowest-emitting cars would no longer have to pay the $16-a-day congestion charge to enter the central city.
The north Italian city of Milan in January launched a one-year trial program requiring drivers who enter an inner zone to buy an "Eco Pass," with cars emitting large quantities of CO2 or running on dirty diesel engines having to pay as much as $14.70 a day. But people who live in Milan's city center face a maximum payment of $387.50 a year; in London, inner-city residents could be paying $12,000 or more.
In a separate London program decreed by the mayor in February, high-polluting trucks driving anywhere in the city must pay a fee of $400 a day. By 2010, the standards for particulate emissions will be tightened again and even large vans, if they are polluters, will be hit with a $200-a-day charge.
Trucking organizations had opposed the program, arguing that it was expensive and would bring few benefits, but it has been overwhelmingly popular among cycling and health groups such as the British Lung Foundation.
The national government has also gotten into the act, last month proposing a new showroom tax of nearly $1,900-per-car after 2010 on high-emission vehicles.
Livingstone said the car emissions program was designed to make sure "that those who choose to carry on driving the most polluting vehicles help pay for the environmental damage they cause."
The goal, he said, is to "have an impact throughout the world, with other cities following suit," and to "start a cultural revolution whereby drivers in every city in Britain start to think about the impact on the environment of their choice of car."
So far, the revolution appears to be shaping up mainly in London, where many in the SUV set are preparing to try to throw Livingstone out on his ear when he comes up for reelection. A YouGov poll last month put Conservative challenger Boris Johnson, who wants to reevaluate the congestion charge, 12 percentage points ahead of Livingstone.