Walking classes also need road space reallocation

EDITOR—We welcome Roberts's editorial, making the health case for the London congestion charge,1 particularly as the revenue is required to be spent on transport. We agree that physically active transport such as walking and cycling is likely to increase. This must be monitored adequately, with attention given to changes in activity levels2 and broken down by sociodemographic groups, to assess the impacts on health and inequalities.

Other potential effects of congestion charging include improvement in access for emergency vehicles. However, not all are positive: the impact of the policy will depend on which complementary measures are introduced at the same time.

Firstly, we disagree that less car travel will result in fewer crashes; this impact is difficult to predict.3 It depends whether journey times are shorter because of less time queuing at junctions or because of higher speeds. If traffic reduction is greater than was predicted, travel speeds may become substantially faster. While shorter journey times could reduce exposure to the risk of collisions, higher speeds could increase the risk by a greater amount.4

Secondly, congestion charging alone could adversely affect equity: road space vacated by people who are deterred by the charge could be occupied by the wealthy, who are less price sensitive.4

Both effects can be effectively combated by simultaneously introducing measures to reallocate road space and giving priority to buses, preferential access to disabled drivers, and effective protection to cyclists and pedestrians.4 This is largely true of the London congestion charge, but it is important to consider when other towns and cities follow suit.

Even London has been timid about pedestrianising road space—Soho and Covent Garden seem ideal candidates. Experience shows that whereas such schemes tend to be initially opposed by local businesses, once the schemes are implemented they benefit economically.

Political polemics are masquerading as science

EDITOR—Roberts in his editorial on congestion charging is wrong in almost all of his assertions.1 The number of cars on the road in central London has remained stable over the past 30 years until it fell by 18% last year (Transport for London statistics). Slow journey times and congestion are due to more people working in central London and poor road management.

Roberts acknowledges that the vulnerable groups are pedestrians (10-18 times the accident rate of car drivers per 2 km journey) and cyclists (13 times the accident rate per 2 km journey), yet he thinks that increasing the size of both of these vulnerable groups by encouraging people to walk or cycle will decrease the number of accidents. Statistical nonsense.

It is generally agreed that the only pollutant to constitute a health hazard at current levels is a small particle emission. How can moving from clean petrol driven cars to dirty diesel buses (buses do not have to conform to any emission standards) help this?

Since there are only about 16 state schools within the congestion charge zone it is absurd to suggest it is going to make mothers happy to allow their children to walk to school throughout the country.

To compare Ken Livingstone to Edwin Chadwick is particularly absurd. Chadwick's plans for sanitation were drawn up at the request of parliament and largely implemented without opposition. He is remembered for his controversial Poor Law Act of 1834, which confined the poor to institutions where families were separated and deliberately subjected to discomfort “to punish them for their indolence.” There may be a case for congestion charges but it is not on the grounds of improving health or safety. I cannot believe that this editorial was critically reviewed before publication.