NMPB-Routes 2008
Emission Parameter
The emission parameter in NMPB-2008 NMPB-2008 is the A-weighted third-octave sound power level per unit length and per vehicle in dB(A). This level calculates from NMPB-2009:
\(L_{W/m}(j)=10 \lg (10^{(L_{W/m/VL}+10 \lg Q_{VL})}+10^{(L_{W/m/PL}+10 \lg Q_{PL})})+R(j)\)
with
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LW/m/VL: sound power level per unit length of the light vehicles, in dB(A)
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QVL: hourly traffic of the light vehicles LV (max. mass m < 3500 kg), in veh/h
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LW/m/PL: sound power level per unit length of the heavy vehicles, in dB(A)
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QPL: hourly traffic of the heavy vehicles HGV (max. mass m >= 3500 kg), in veh/h
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R(j): third-octave values of the reference spectrum for road noise, in dB(A)
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j: running number of octave
In CadnaA, traffic counts can be entered for the total amount per day MDTD (=TMJA), or as overall traffic flow Q (in vehicles/hour) and the percentage of heavy vehicles p%. The relations between MDTD|TMJA and Q and p% are stated in section „MDTD (TMJA)“ below.
Dialog Road (for NMPB 2008)
Emission Parameter LwA’
The emission parameter displayed on the dialog Road is the A-weighted total sound power level per unit length L’Aw in dB(A) according to:
\(L'_{wA}(j)=10 \lg \sum_{j=1}^{18} 10^{0.1*L_{W/m}(j)}\)
In this case, always the emission spectrum for non-porous surfaces is used.
Traffic Data
The noise emission is calculated from traffic data based on the daily periods Day (6-18 h) and Night (22-6 h). The day may be subdivided into two further periods: 6-18 h (Day) and 18-22 h (Evening). The emission is estimated according the following specifications depending on:
- the „Mean Daily Traffic Density“ (MDTD, veh/24h) or „Annual Average Daily Traffic“ (AADT, veh/24h) or the „trafics moyens journaliers annuels“ (TMJA, veh/24 h),
- the daily time period,
- the number of lanes (for urban and inter-urban roads).
In any case, the emission is limited to the emission caused by a so-called „maximum traffic flow“ situation („émission sonore maximale du flot“).
Road Types (urban roads)
For urban roads no input of MDTD or TMJA is possible. Instead, traffic data must be based on hourly counts Q and p% directly in dialog section „Exact Count Data“. NMPB 2008, table 2.2, specifies TMJA-ranges in combination with ranges of the percentage of heavy vehicles %PL for urban roads where no other data is available:
| Road Type | TMJA | %PL | %HPS | %TV daytime | %TV nighttime | |
| veh/day | daytime (6-22 h) | nighttime (22-6 h) | ||||
| Voiries structurantes urbaines | 17000 to 217000 | 5 to 20% | 5 to 35% | 7,5 to 9,5 | - | |
| Voiries urbaines intersecteurs | 2500 to 25000 (Île-de-France: 50000) | 0 to 5% | 6,5 to 9,5 | 85 to 95% | 15 to 5% | |
| Voiries urbaines de secteurs | ||||||
Road Types (non-urban roads)
For the reference times D/E/N = 12/4/8 h the TMJA LV for the light vehicles (LV) calculates from the total TMJA in vehicles per day NMPB-2009:
\(TMJA\:LV = TMJA*(\frac{1-HGV\%}{100})\)
resulting in the following LV flow rates per road type and daily period:
| Flow Rate Q_LV per Daily Period (LV veh/h) | |||
| Road Type | D: 6 - 18 h | E: 18 - 22 h | N: 22 - 6 h |
| Motorway long distance, 16/18/20/22/24/26/28 or 30 HGV% | TMJA LV/17 | TMJA LV/19 | TMJA LV/82 |
| Motorway regional, 6/8/10/12/14/16/18/20/22/24/26/28/30/32 or 34 HGV% | TMJA LV/17 | TMJA LV/18 | TMJA LV/100 |
| Intercity long distance, 8/10/12/14/16/18/20/22/24/26/28/30/32 or 34 HGV% | TMJA LV/17 | TMJA LV/19 | TMJA LV/110 |
| Intercity regional, 5/7/9/11/13/15 or 17 HGV% | TMJA LV/17 | TMJA LV/19 | TMJA LV/120 |
The TMJA HGV for the heavy vehicles (HGV) calculates from:
\(TMJA\:HGV = TMJA*(\frac{HGV\%}{100})\)
resulting in the following HGV flow rates per road type and daily period:
| Flow Rate Q_HGV per Daily Period (HGV veh/h) | |||
| Road Type | D: 6 - 18 h | E: 18 - 22 h | N: 22 - 6 h |
| Motorway long distance, 16/18/20/22/24/26/28 or 30 HGV% | TMJA HGV/20 | TMJA HGV/20 | TMJA HGV/39 |
| Motorway regional, 6/8/10/12/14/16/18/20/22/24/26/28/30/32 or 34 HGV% | TMJA HGV/17 | TMJA HGV/28 | TMJA HGV/50 |
| Intercity long distance, 8/10/12/14/16/18/20/22/24/26/28/30/32 or 34 HGV% | TMJA HGV/17 | TMJA HGV/27 | TMJA HGV/51 |
| Intercity regional, 5/7/9/11/13/15 or 17 HGV% | TMJA HGV/16 | TMJA HGV/34 | TMJA HGV/73 |
From these figures, the number of vehicles/hour Q as displayed on the Road dialog calculates from:
\(Q=Q_{LV}+Q_{HGV}\)
and the percentage of heavy vehicles p(%) as displayed calculates from:
\(p\%=\frac{Q_{HGV}}{Q_{LV}+Q_{HGV}}*100\)
Deprecated Road Types
Besides the above mentioned road types the following road types have been available in former releases of CadnaA, but are deprecated due to a revised interpretation of the NMPB 2008 emission scheme, beginning from CadnaA 2019 release:
- Motorway long distance Deprecated
- Motorway regional Deprecated
- Intercity long distance Deprecated
- Intercity regional Deprecated
In addition, the following road types from the German VBUS VBUS-2006 (see RLS-90, MDTD - VBUS) have been available, but are also deprecated due to not fitting with the French road types:
- Motorway
- Federal Road
- Ordinary Road
- Local Road
Note
These deprecated road types are still listed on the bottom of the list box „Road Type“, in order to inform users of a possibly formerly selected, but wrong or unsuitable road type.
Speed Correction
The maximum speed is 130 km/h for autos, and 100 km/h for trucks.
NMPB 2008 states that the speed of autos is equivalent to the indicated maximum speed of a road while the maximum speed of trucks are depending on road type. In CadnaA, however, the speed of trucks has to edited by the user as these road types do not combine with the road types used for MDTD/TMJA.
| Road Type | Speed of Trucks PL (km/h) |
|---|---|
| highway interconnection | 90 |
| speed lane, urban | 90 |
| road with separated carriage ways | 85 |
| road with single carriage ways | 80 |
| in agglomerations | indicated speed |
Reference Spectrum
The values R(j) of the weighting spectrum are listed in the following table:
| third-octave band center frequency (Hz) | 100 | 125 | 160 | 200 | 250 | 315 | 400 | 500 | 630 |
|---|---|---|---|---|---|---|---|---|---|
| porous surfaces | -22 | -22 | -20 | -17 | -15 | -12 | -10 | -8 | -9 |
| non-porous surfaces | -27 | -26 | -24 | -21 | -19 | -16 | -14 | -11 | -11 |
| third-octave band center frequency (Hz) | 800 | 1000 | 1250 | 1600 | 2000 | 2500 | 3150 | 4000 | 5000 |
|---|---|---|---|---|---|---|---|---|---|
| porous surfaces | -9 | -10 | -11 | -12 | -13 | -16 | -18 | -20 | -23 |
| non-porous surfaces | -8 | -7 | -8 | -10 | -13 | -16 | -18 | -21 | -23 |
Source Description
For each vehicle category, the emission (sound power level per unit length) consists of two components:
\(L_{W/m/veh}=10 \lg (10^{0.1*Lr_{W/m}}+10^{0.1*Lm_{W/m}})\)
with
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Lr_W/m: rolling noise, due to tire-road interaction, called „roll noise“
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Lm_W/m: mechanical sources of the vehicles, called „engine noise“
Roll Noise
The roll noise component for three types of road surface (R1, R2, R3) is given in the next table („average emission for an aged surface less than ten years old“):
| Attribute ValueSTRONR | Road Surface Category |
Speed Range v (km/h) Autos (VL) |
Speed Range v (km/h) Trucks (PL) |
| LWA’ (dBA/m) (20 <= v <= 130) |
LWA’ (dBA/m)(20 <= v <= 100) | ||
| 1 | Revêtement R1 | 53,4 + 21 log (v/90) | 61,5 + 20 log (v/80) |
| 2 | Revêtement R2 | 55,4 + 20,1 log (v/90) | 63,4 + 20 log (v/80) |
| 3 | Revêtement R3 | 57,5 + 21,4 log (v/90) | 64,2 + 20 log (v/80) |
| 4 | Revêtement R1 drainant | as for Revêtement R1 | as for Revêtement R1 |
| 5 | Revêtement R2 drainant | as for Revêtement R2 | as for Revêtement R2 |
| 6 | Revêtement R3 drainant | as for Revêtement R3 | as for Revêtement R3 |
Regarding the roll noise component the following comments apply:
- Porous and non-porous surfaces have the same speed correction, however, a different spectrum is used (see Reference Spectrum).
- By the three surface categories R1 to R3 several road surface types are grouped. For examples see NMPB-2008, section 2.7.2.1.
- The road surface categories „Revêtement R2 drainant“ and „Revêtement R3 drainant“ are not listed in NMPB 2008, but have been introduced in CadnaA based on French user requests.
Age of Road Surface
NMPB-2008 corrects for the deterioration of the road surface with time as specified by the table below (with a: age of road surface in years):
| Road Surface Category |
VL (light vehicles) | PL (heavy goods vehicles) | ||
| <= 2 years | 2 to 10 years | <= 2 years | 2 to 10 years | |
| R1 | -4 | 0.5*(a - 10) | -2.4 | 0.3*(a - 10) |
| R2 | -2 | 0.25*(a - 10) | -1.2 | 0.15*(a - 10) |
| R3 | -1.6 | 0.2*(a - 10) | -1 | 0.12*(a - 10) |
The „Year of Construction of Surface“ is specified on each dialog Road while the „Year of Calculation“ is specified on the dialog Configuration, „Road“ tab, with NMPB-2008 selected (see NMPB-Routes 2008).
Note
Since the road surface definition in NMPB 2008 applies different speed corrections for Autos and Trucks, combined with an even more complex scheme for aging, it is not possible - in opposite to NMPB 1996 (see NMPB-Routes 1996) - to enter user-defined road surfaces in CadnaA.
Engine Noise
With engine noise the following effects influence the radiated noise:
- traffic flow condition, five different situations apply:
- stabilisée,
- accélération,
- décélération,
- troncons de démarrage,
- troncons d'arrêt.
- road gradient, three different situations apply:
- horizontal (gradient <= 2% absolute),
- increasing (gradient 2 to 6%),
- decreasing (gradient -2 to -6%)
Gradients larger to 6% (absolute) do not increase the correction.
Note
For the time being, the respective equations for all engine noise situations are not stated here.
Source Geometry
The height entered in the dialog Geometry is the height of the road’s surface. The source height is 0.05 m above the road’s center line or above of the center lines of the outer lanes.
Traffic Flow
The selected type of traffic flow applies to all daily periods D/E/N. Available types are:
- stabilisée
- accélération
- décélération
- troncons de démarrage
- troncons d'arrêt
Button DEN 
Clicking this button in line „Traffic Flow“ enables to define different types of traffic flow for the time periods Day|Evening|Night.
Note
The following object attributes are available: FLOWNRD/E/N (read/write), FLOWD/E/N (read only, for details see Table Object Attributes in the manual „Attributes, Variables and Keywords“).
Correction for Multiple Reflections
There is no global correction available in NMPB-2008 to correct for multiple reflections. However, CadnaA enables to restrict the calculation using image sources to the 1st order of reflection and to correct for multiple reflections according to RLS-90 RLS-1990.
see NMPB-Routes 2008 and RLS-90