Extensive changes to UN R51 as developed mainly by the informal working group on Additional Sound Emission Provisions (ASEP II), but including further proposals submitted through GRB. All of these proposals were consolidated by GRB during its September 2017 session in Annex II to the session report. GRB intends to hold a final review of the changes, including whether they constitute a new series of amendments, during its January 2018 session, (i.e., prior to the March 2018 WP.29 session that will consider this document). The draft changes include proposals to

1. amend the scope to be design-neutral and reflect the driving situations covered by the Regulation;
2. highlight that ASEP apply to vehicles and their electric sound enhancement systems such as the Audible Vehicle Alert System (AVAS) and silencers equipped with an active cancelling system
3. update the “backfire” assessment procedure; and
4. clarify the gear ratio anchor point in Annex 7 as defined via Annex 3
5. Paragraph 1: The scope was originally drafted for the Annex 3 test which refers to normal urban driving. A proposed additional sentence covers the intention of Annex 7.
6. Paragraph 2.8.1.: Adopt the wording from standard ISO 362-1:2015 for clarity. If an electric motor is not operational during the type approval tests, then its power must not contribute to the calculation of the power to mass ratio (PMR).
7. Paragraph 2.24., table: Amendments regarding paragraph 2.2.7.4. of Annex 3 because paragraph 2.2.7.4. is new. Amendments also for line BB’ to reflect that the measurement will not end after line BB’. For the speeds vAA’, vBB’ and vPP’, a wrong reference coming from ISO was corrected.
8. Paragraph 2.27.: A new definition of “kickdown” was introduced since this term is used in this Regulation. With a large variety of products, it is unclear what “kickdown” exactly means. This definition is a design neutral approach and reflects the intention of Annex 3 and Annex 7.
9. Paragraph 2.28.: Prevention of downshift is a legal measure to ensure that the vehicle can be tested within the test conditions as specified by this Regulation.
10. Paragraph 3.3.: Deletion of meaningless sentence given the requirement that the vehicles have to be loaded in order to be able to achieve the urban driving conditions as described in paragraph 3.1.2.2. of Annex 3. The sentence has similarly already been deleted in Regulation (EU) No. 540/2014.
11. Paragraph 6.2.3.: Amend paragraph 11.6 to exempt vehicles with a serial hybrid drive train until July 2022 from ASEP since these vehicles do not have the internal combustion engine running within the control range of Annex 7 and therefore cannot yield valid test results.
12. Annex 1, Appendix 1: For the test method according to 3.1.2.1 the pre-acceleration length may differ per gear ratio. In this case, it is necessary to report the pre-acceleration length per gear ratio.
13. Annex 1, Appendix 2: Missing elements of the information document have been added, namely “0.2. type” and “3.2.6. pressure charger(s)”.
14. Annex 3, paragraph 2.1.: Lower temperatures will lead to slightly higher test results due to an increased tyre rolling sound. Thus, testing at lower temperatures will be a disadvantage for the manufacturer. If for practical reasons the manufacturer wishes to carry out tests at lower temperatures, this shall be accepted by the type approval authority.
15. Annex 3, paragraph 2.2.1.: For M1 and N1, the current provision has led to ambiguities about its meaning. The proposed new sentence clarifies the meaning. Further, the tolerances are broadened, as research shows, that the impact of the test mass can be neglected in a wide range. For M2, M3, N2 and N3, the current provision has led to ambiguities about its meaning. The proposed new sentence clarifies the meaning. If the test mass of the vehicle is equal to the target mass, the target mass shall be achieved with a tolerance of ±5 per cent according to equation (2) in paragraph 2.2.7.1. of Annex 3. Consequently this has to be valid also for the test mass mt. If the test mass of the vehicle is lower than the target mass according to equation (12) and (13) in paragraph 2.2.7.1. of Annex 3, the test mass shall be achieved with a tolerance of ±5 per cent. Concerning M2 and M3, for clarification and to avoid misunderstanding, the loading conditions for complete vehicles of category M2 (M > 3,500 kg) and M3 were aligned with the requirements for incomplete vehicles of category M2 (M > 3,500 kg) and M3. As a consequence, vehicles of category M2 (M ≤ 3,500 kg) have to be added to the table and their test mass requirement has to be aligned with those of vehicles of category M1 and N1.
16. Annex 3, paragraph 2.2.6.: add conditioning provisions for exhaust systems containing fibrous materials,
17. Annex 3, paragraph 2.2.7.1.: See the above justification for M2, M3, N2 and N3 in paragraph 2.2.1.
18. Annex 3, paragraph 2.2.7.4.: If a manufacturer does not produce vehicles with two axles only, he is not able to calculate the right test mass for his vehicles with more than two axles. For calculating the test mass, a vehicle with two axles has to be put on a scale to measure the unladen front axle load, mfa load unladen, and the unladen rear axle load, mra load unladen, for being able to calculate munladen as given in formula (3) of paragraph 2.2.7.1. of Annex 3. In addition, a new paragraph provides a procedure for calculating the test mass of a virtual vehicles with two axles, based on an existing vehicle with more than two axles, when a vehicle with two axles is physically not available to be put on a scale.
19. Annex 3, paragraph 3.1.2.1.: Proposal to extend the measurement to a position where misfiring is detectable. A redundant sentence is deleted per paragraph 2.2.4.
20. Annex 3, paragraph 3.1.2.1.4.1.(d): Clarify gear usage where one gear ratio is above 2 m/s² and the other below a_urban.
21. Annex 3, paragraph 3.1.2.1.4.1.: Clarify the proper setup for testing for vehicles with very short gear ratios.
22. Annex 3, paragraph 3.1.2.1.4.3.: Introduction of specifications for vehicles with only one gear ratio.
23. Annex 3, paragraph 3.1.2.1.5.: Simplify testing. With a fixed vehicle length, it is not necessary to adjust the test equipment (light barriers, pylons) for each vehicle.
24. Annex 3, paragraph 3.1.2.2.1..: Clarify the gear ratio selection procedures,
25. Annex 3, paragraph 3.2.3.: Reference correction
26. Annex 3, paragraph 3.2.5.3.: Reference correction
27. Annex 4, paragraph 1.: The performance of the fibrous material can be checked by completely removing the fibrous material. This reintroduces an option removed when Annex 5 of the 02 series of amendments was revised.
28. Annex 6, paragraph 2.1.: Proposal to simplify and clarify CoP. During the conformity of production procedures, neither the vehicle nor tyres will have a proper preconditioning. In many cases, the vehicles are foiled and parts may be missing as theft protection. It is very unlikely that the vehicles will have already the same performance as the type approval vehicle. This provision adopts the specifications from the revised ASEP provisions (Informal document GRB-65-26, Annex 7, para. 1). In addition, the range of masses was broadened in the same way as proposed for type approval.
29. Annex 6, paragraph 3.: Reference correction.