To ask the Secretary of State for Transport what steps she is taking to ensure that technologies aimed at enabling vehicles to meet European standards for nitrogen oxides and particulate matter emissions are installed and maintained in optimum ways, with particular reference to selective catalytic reduction. (151144)

As I mentioned in my answer of 9 July 2007, Official Report, columns 1193-94W, from November 2007 new HGV and bus engines will be required to monitor their emission control systems and to limit engine power in the event of those emission control systems failing to operate. These provisions are essential to encourage operators to keep the emission control systems properly maintained and working, and so ensure that the intended reductions in emissions of Oxides of Nitrogen (NO_X) from current and future standards are actually delivered in operation.

The provisions apply equally to all HGV and bus engines, whether they are using exhaust gas recirculation or selective catalytic reduction, but may be of particular relevance where selective catalytic reduction is being used and the effectiveness of the system could be compromised by a simple omission, on the part of the vehicle operator or driver, to top up the AdBlue reagent.

In the case of engines using selective catalytic reduction (SCR), a level indicator for the AdBlue reagent, incorporating a low level warning, will be required to be displayed on the dashboard near the fuel gauge, and the On Board Diagnostic system will be required to monitor the quality, as well as the presence, of the reagent. On Board Diagnostic systems are also required to monitor for failures which could lead to increased particulate emissions.

Using an SCR equipped vehicle with an empty AdBlue tank would be an offence under regulation 61 a of the Road Vehicles (Construction and Use) Regulations 1986, as amended, in that it will lead to excess emissions which could have been avoided by routine maintenance.