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Diesel Fumes

Volume 201: debated on Friday 20 December 1991

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To ask the Secretary of State for Transport what arrangements exist to monitor the exhaust emission levels from diesel vehicles in general and London taxi-cabs in particular; and what further checks he proposes to control the exhaust emissions from diesel engines.

Large diesel-powered vehicles are inspected annually and at roadside checks for the cleanliness of their exhaust emission by the Department's vehicle inspectorate. This is at present a subjective assessment of the level of smoke emitted. Testing using smoke measuring instruments will be introduced in 1992.Taxis are subject to a roadworthiness test after one year from new. Taxis are usually submitted not to an annual MoT roadworthiness certificate but to an alternative test, conducted by the licensing authority, which is generally more stringent than the MoT test.The licensing authority, which for taxis in London is the Public Carriage Office, has the power to carry out spot checks on a taxi at any time during the licensed year and can prohibit use of the vehicle until faults, which may include excessive smoke, are rectified. The Public Carriage Office is also currently liaising with Westminster council to set up a complaints hot-line for, among other vehicles, taxis which smoke excessively.For the future, studies are under way to determine the extent to which smoke measuring instruments can be adapted or modified for use on diesel-powered cars, taxis and light vans.