§ Mr. HallTo ask the Secretary of State for Transport what measures he proposes to introduce to prevent motorists readjusting the exhaust systems of their vehicles after the annual vehicle test in such a way as to increase emissions.
§ Mr. Kenneth CarlisleNone. The primary purpose of the annual test is to encourage motorists to maintain their vehicles in a good state of tune. Having done so, there should be little incentive for the motorist to readjust the vehicle away from this optimum setting. Those owners who nevertheless might be so inclined would be committing an offence under regulation 61(7) of the Road Vehicles (Construction and Use) Regulations 1986.
§ Mr. HallTo ask the Secretary of State for Transport what consideration was given to the inclusion of a test for levels of oxides of nitrogen in exhaust emissions in the annual vehicle test; and if he will make a statement.
§ Mr. Kenneth CarlisleThe MOT test measures emissions of carbon monoxide and hydrocarbons at idle speed. This simple "no load" test is designed for non-catalyst cars and is quite adequate to check the correct tune state of these vehicles. To carry out a meaningful check on the emissions of oxides of nitrogen, which occur only when the engine is under load, would require every MOT station to be equipped with very expensive chassis dynamometer and associated control equipment. A modified test for catalyst cars will be introduced before 1997 in accordance with EC directive 92/55/EEC. This modified test will check the correct functioning of the catalyst to ensure that NOx controls are operating.