The Commission shall, not later than 31 December 2007:
re-assess its non-road emission inventory estimates and specifically examine potential cross-checks and correction factors;
consider the available technology, including the cost/benefits, with a view to confirming Stage III B and IV limit values and evaluating the possible need for additional flexibilities, exemptions or later introduction dates for certain types of equipment or engines and taking into account engines installed in non-road mobile machinery used in seasonal applications;
evaluate the application of test cycles for engines in railcars and locomotives and, in the case of engines in locomotives, the cost and benefits of a further reduction of emission limit values in view of the application of NOx after-treatment technology;
consider the need to introduce a further set of limit values for engines to be used in inland waterway vessels taking into account in particular the technical and economic feasibility of secondary abatement options in this application;
consider the need to introduce emission limit values for engines below 19 kW and above 560 kW;
consider the availability of fuels required by the technologies used to meet the Stage IIIB and IV standards levels;
consider the engine operating conditions under which the maximum permissible percentages by which the emission limit values laid down in Section 4.1.2.5 and 4.1.2.6 of Annex I may be exceeded and present proposals as appropriate to technically adapt the Directive in accordance with the procedure referred to in Article 15 of Directive 97/68/EC;
assess the need for a system for "in-use compliance" and examine possible options for its implementation;
consider detailed rules to prevent "cycle beating" and cycle by-pass;
and submit, where appropriate, proposals to the European Parliament and the Council.