Division: Individual vehicle - Commission Directive (EU) 2015/996 of 19 May 2015 establishing common noise assessment methods according to Directive 2002/49/EC of the European Parliament and of the Council (Text with EEA relevance)

In the traffic flow, all vehicles of category m are assumed to drive at the same speed, i.e. v_m , the average speed of the flow of vehicles of the category.

A road vehicle is modelled by a set of mathematical equations representing the two main noise sources:

1..

Rolling noise due to the tyre/road interaction;
2..

Propulsion noise produced by the driveline (engine, exhaust, etc.) of the vehicle.

Aerodynamic noise is incorporated in the rolling noise source.

For light, medium and heavy motor vehicles (categories 1, 2 and 3), the total sound power corresponds to the energetic sum of the rolling and the propulsion noise. Thus, the total sound power level of the source lines m = 1, 2 or 3 is defined by:

L_{W,i,m} (v_{m}) = 10 \times \lg (10^{L_{WR,i,m} (v_{m}) ∕ 10} + 10^{L_{WP,i,m} (v_{m}) ∕ 10})

(2.2.2)

where L_WR,i,m is the sound power level for rolling noise and L_WP,i,m is the sound power level for propulsion noise. This is valid on all speed ranges. For speeds less than 20 km/h it shall have the same sound power level as defined by the formula for v_m = 20 km/h.

For two-wheelers (category 4), only propulsion noise is considered for the source:

L_{W,i,m = 4} (v_{m = 4} ) = L_{WP,i,m = 4} (v_{m = 4} )

(2.2.3)

This is valid on all speed ranges. For speeds less than 20 km/h it shall have the same sound power level as defined by the formula for v_m = 20 km/h.

Division Individual vehicle