TRL was commissioned by the DETR to assess the suitability of models and databases to estimate traffic emissions through traffic management schemes and to develop a methodology to update heavy-duty vehicle emission factors for use in an appropriate model. A wide variety of models were reviewed and assessed, these included those which are used for estimating vehicle emissions over an entire region to those that estimate emissions from specific types of vehicles using a pre-defined speed cycle and road layout. A few models were identified which may be suitable for estimating heavy vehicle emission levels through traffic calming schemes, but would need supplementing with 'representative' emission data before they could be used. In a separate project a range of vehicles will be instrumented to measure key engine parameters whilst they are driven through a selection of traffic management schemes. It is proposed that the engine speed and load measurements are then reproduced on a chassis or engine dynamometer using a variety of engines of an equivalent size or power rating that are in common use. In this manner the emissions produced by vehicles passing through traffic management schemes can be directly estimated and used as a database for use in emission prediction models. (A)

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