Effective car driving schemes to cut pollution

By Karl Mathiesen/Guardian News & MediaLicence-plate driving bans such as the one implemented in Paris this week are not the solution to urban air pollution, according to analysis of recent data. In fact, arbitrary restrictions have been shown to make air pollution worse in the long term.Long-running licence plate schemes operate in many cities, including Athens, Beijing and Mexico City. Some ban cars every second day, others once a week. But drivers inevitably circumvent restrictions by buying cheap, inefficient cars with opposing number plates, according to Lucy Sadler, who runs the Low Emission Zones in Europe website. This means some schemes have had an adverse effect on air quality.“Certainly, in terms of comparison between low emission zones and odd-and-even number plate schemes, it’s a no-brainer,” Sadler said. “There is lots of good evidence saying low emission zones have a good impact on air quality and health. That’s robust and well researched.”“As the (licence plate) traffic restriction can also affect cleaner vehicles, there is no incentive for motorists to invest in cleaner cars with particle filters or catalysts,” said Martin Lutz, from Berlin’s Department for Urban Development and Environment.Lutz agreed that low emission zones (LEZs) , hundreds of which now operate in Europe since Stockholm implemented the first in 1996, are a more effective way of decreasing the contribution of traffic to air pollution. LEZs ban inefficient vehicles from city centres, forcing drivers to upgrade their cars.On Monday, the French government reacted to dangerous levels of pollution by requiring cars with licence plates ending with an even number to stay off the road. Nearly 4,000 fines of 22 euros were issued to drivers who flaunted the restriction. It was the second time Paris had implemented a short-term ban in response to high smog levels; the city’s air quality authority, Airparif, says such measures are effective in combating pollution emergencies.But Ben Barratt, from King’s College London, said the effect of short-term actions is difficult to assess. “The weather changes all the time, the emissions change all the time and trying to pin down whether a particular emergency scheme works or not is hard.” Short-term schemes also cause mass disruption and dissatisfaction, Sadler added.“The impact to society and to vehicle operators is horrendous. Suddenly, tomorrow, you’re not allowed to move.”Research on the impact of licence plate-based schemes is rare, but an analysis of existing data shows a mixed set of results. Conversely, LEZs and congestion charges, which encourage drivers to use public transport and shift to more efficient cars, are proven to reduce concentrations of dangerous particles and chemicals which cause more than 1.3mn premature deaths in cities every year.Asked if it was fair to place the burden on drivers, particularly low-income drivers, Sadler said those who earned less tended to use public transport, and the responsibility for the pollution created by cars should ultimately rest on the person at the wheel. “If somebody’s polluting, why should society subsidise that? In air pollution, the polluter pays in principle.”But according to Barratt, LEZs should be used alongside inner-city congestion charges, as they are in London: “You have to take the vehicles off the road, rather than just try and make them cleaner. So something like congestion charging, where you’ve got a marked decrease in the number of vehicles on the road, is preferable to something where you’ve got the same number of vehicles, (even if) those are cleaner.”