4. Without prejudice to paragraph 1, in order to avoid modifications or adjustments with adverse effects on the functional safety or on the environmental performance of the vehicle, the manufacturer shall endeavour, through the use of best engineering practice, to prevent such modifications or adjustments from being technically possible, unless such modifications or adjustments are explicitly declared and contained in the information folder and thus covered by the type-approval.

2.1.2. Improvements in light-duty vehicles are necessary

2. Member States shall be authorised to require that the speed limitation device in vehicles registered in their territory and used exclusively for the transport of dangerous goods is set in such a way that those vehicles cannot exceed a maximum speed of less than 90 kilometres per hour.

6.2.1. Headlamps shall be fitted with a device enabling them to be so adjusted on the vehicles as to comply with the rules applicable to them.

4. Notwithstanding paragraph 2, Member States which introduce a system of road user charges for motor vehicles or articulated vehicle combinations intended exclusively for the carriage of goods by road may apply a reduced rate on gas oil used by such vehicles, that goes below the national level of taxation in force on 1 January 2003, as long as the overall tax burden remains broadly equivalent, provided that the Community minimum levels are observed and that the national level of taxation in force on 1 January 2003 for gas oil used as propellant is at least twice as high as the minimum level of taxation applicable on 1 January 2004.

The settings of the engine of the test vehicle, particularly the fuel feed (carburetter or injection system) shall conform to the specifications of the vehicle manufacturer.