Professor Phil Goodwin, the foremost expert on traffic reduction, has expressed his view that projections of increased traffic and pollution due to Option 1 were not 'fair and accurate'.
A report commissioned by campaigners against the scheme used the very worst case scenario to project increased traffic on nearby streets, figures that were seized upon my the campaigners, with Robert Kelsey declaring them as 'fair and accurate'.
In contrast, Professor Phil Goodwin declared his belief that the report's predictions were not 'the most realistic scenario', and stated (as Option 1 supporters have said throughout), that we cannot know what the impact of a scheme will be until after a trial period.
Professor Goodwin, Emeritus Professor of Transport Policy at UCL, and the author of the principal research into traffic evaporation.
Robert Kelsey is the author of a self-help book.
While the atmosphere in the country seems to be against giving heed to the experts, perhaps the events of the last few days suggest that we should start paying a bit more attention to what experts have to say.
So what does the expert say? He says that a) traffic evaporation is a common and significant occurrence, and b) a 'catch-all' rate of evaporation must not be used, but rather it needs to be assessed on a case by case basis, preferably using a real world trial.
Much of the debate of the traffic reduction scheme has been centred around the idea that changing the infrastructure of the area will lead to a reduction in the amount of motor traffic - otherwise known as 'traffic evaporation'. Supporters of Option 1 have highlighted the likelihood that Option 1 would reduce traffic levels overall and therefore reduce pollution overall. Those against change disagreed, arguing that motor traffic would simply cause increased congestion on nearby streets and therefore increase pollution.
Fortunately, there is research on the impact of traffic evaporation, and that it is well recognised and common occurrence. Unfortunately those against trying out whether it would occur decided to misuse the evidence to their own ends.
The main research on the subject was conducted by Professor Phil Goodwin et al (1998), which showed that motor traffic reduced when road conditions were changed. There was good evidence to show that changes to road conditions led to changes in people's transport behaviour such as increasing the proportion of people walking, cycling and taking public transport, but also through changes in trip frequency, time of travel, or changes such as combining two trips into one. While the scale of change differed from place to place, the vast majority saw significant levels of 'evaporation'. The median percentage drop was 11% (although several other - higher - figures could have been used if someone wanted to use a default figure). However, the researchers explicitly advised against using their research to justify using any figure to assume a particular level of evaporation. The research showed that evaporation was a real and common phenomenon, and that the extent of evaporation could only be assessed on a scheme by scheme basis.
Claims of traffic increases
Despite the explicit warning of the researchers, opponents of the scheme commissioned TTHC to write a report to analyse the impact of Option 1. The report predicted that Option 1 would lead to increased pollution on Queensbridge Road and Richmond Road.
The commissioned report bases its judgements from an evaporation figure of 11% - a figure that the researchers explicitly warned against using.
The TTHC report used the very worst case scenarios for their projections. Professor Goodwin has written why the report's conclusions are the very worst case scenario, and therefore extremely unlikely to be accurate. He states that there is "very extensive experience that expected excessive traffic problems on alternative route nearly always turns out to be exaggerated, because travel patterns are more flexible and adaptable than assumed". He concludes that we cannot know, and should not make judgements on, what the scale of evaporation will be, until after an experimental period.
Using a trial:
Matters of pollution, health, quality of life and efficiency of transport are too important to be impacted by people with a vested interest in keeping the status quo. A trial, using as much data as we can reasonably be gathered, must be used to implemented in order to arrive at the best solution.
We are a group of local residents who walk, drive and cycle. We support Hackney's traffic and pollution reduction plans. We firmly believe this scheme will help make London Fields a better place to live. We look forward to working with all of our neighbours and the council to make this scheme a success.