§ Mr. Todd
To ask the Secretary of State for the Environment, Transport and the Regions, pursuant to his answer of 15 April 1999,Official Report, column 299, what methodology will be used to assess the impact of the fuel duty escalator on transport emissions and when an accurate assessment of impact will be prepared. 
§ Ms Glenda Jackson
We draw on a number of forecasting techniques to estimate the impact of the fuel duty escalator on emissions. These techniques principally focus on the long-term, since the fuel duty escalator is a long-term policy. Our forecasting methods are kept under review, and adjustments are made as and when improved techniques or new data become available.
To some degree all these methods rely on statistical analysis of historic data, and we suspect that we will need a number of further years' traffic and emissions data before we can make a definitive short-term assessment of the impact of fuel duty increases since 1996. Even then, such an assessment will remain reliant on forecasts of what would have happened had the increases not been implemented, and will not pick up the full effects of the policy which will only become apparent over the longer term. Work in this area continues, and we will make available short-term estimates to complement the longterm estimates we have already published, once these can be provided with an acceptable degree of reliability.