Czech Method
Emission Parameter
The emission parameter according to the Czech Method is the A-weighted equivalent continuous sound pressure level LAeq,7.5m at a reference distance of 7.5 m from the center line of the outer lane of an infinite straight road with free sound propagation Koz-Lib-1996.
Emission Level LAeq,7.5m
The mean level LAeq,7.5m calculates from:
\(L_{Aeq,7.5m}=10 \lg X-10.1\) in dB(A)
with the correction X:
\(X=F_1*F_2*F_3\)
with
- F1: influence of the speed of the traffic flow and the percentage of the lorries,
- F2: influence of the road gradient (slope), and
- F3: influence of the road pavement.
Dialog Road (for Czech Method)
The factor F1 is calculated separately for daytime (6-22 h) and nighttime (6-22 h) according to:
\(F_1=n_{OA}*F_{vOA}*10^{L_{OA}/10}+n_{NA}*F_{vNA}*10^{L_{^NA}/10}\)
with
-
nOA:average traffic flow per hour of the cars (Day or Night)
-
nNA:average traffic flow per hour of the lorries and buses (Day or Night)
-
FvOA:speed dependence of the equivalent sound pressure level on the traffic flow consisting from the cars only (see below)
-
LOA:A-weighted sound pressure level of the passenger cars for the year under consideration, given in the table in section „Particular Years“ (see below)
-
FvNA:speed dependence of the equivalent sound pressure level on the traffic flow consisting from the lorries and buses only (see below)
-
LNA:A-weighted sound pressure level of the lorries and buses for the year under consideration, given in the table in section „Particular Years“ (see below)
FvOA is given by:
- \(F_{vOA} = 3.59*10^{-5}*v^{0.8}\) for v <= 60 km/h
- \(F_{vOA} = 2.70*10^{-7}*v^{2}\) for v > 60 km/h
FvNA is given by:
- \(F_{vNA} = 1.50*10^{-2}*v^{-0.5}\) for v <= 60 km/h
- \(F_{vNA} = 2.45*10^{-4}*v^{0.5}\) for v > 60 km/h
Particular Years
Particular sound pressure level LOA (in dB) for cars, and LNA (in dB) for trucks and buses for years 1995-2005 are given in the next table.
| Year | level LOA cars, dB(A) |
level LNA trucks and buses, dB(A) |
|---|---|---|
| 1995 | 77.9 | 85.4 |
| 1996 | 77.4 | 84.7 |
| 1997 | 76.8 | 84.0 |
| 1998 | 76.2 | 83.3 |
| 1999 | 75.6 | 82.4 |
| 2000 | 74.9 | 81.4 |
| 2001 | 74.8 | 81.1 |
| 2002 | 74.6 | 80.9 |
| 2003 | 74.4 | 80.7 |
| 2004 | 74.3 | 80.4 |
| 2005 | 74.1 | 80.2 |
Specification of Emission
MDTD
Specifying the „Mean Daily Traffic Density“ (MDTD, veh/24h) calculates the emission level LAeq,7.5m depending on the road type based on the hourly traffic data M (veh/h) and the truck proportion p (%) according to the table below.
| Attribute Value STRGATTNR |
Road Type | daytime (6-22 h) | nighttime (22-6 h) | ||
| M *1) (veh/h) | p *2) (%) | M *1) (veh/h) | p *2) (%) | ||
| 0 | Motorway | 0.0563 DTV (=0.9/16) | 25 | 0.0125 DTV (=0.1/8) | 12.5 |
| 1 | Landscape mixed | 0.0581 DTV (=0.93/16) | 20 | 0.0087 DTV (=0.7/8) | 10 |
| 2 | Settlement mixed | 0.06 DTV (=0.96/16) | 20 | 0.005 DTV(=0.04/8) | 10 |
| 3 | Recreational | 0.0606 DTV (=0.97/16) | 10 | 0.0038 DTV (=0.03/8) | 3 |
*1) M = nOA + nNA
*2) p = nOA/(nOA + nNA) * 100%
Exact Count Data
Any number of vehicles per hour M and other proportions of trucks p% can be specified when selecting this option.
LAeq,7.5m
for direct input of the emission level
Diurnal Patterns
see Common Input Data, Diurnal Pattern
Speed Limit (km/h)
The speed correction in CadnaA is based on the speed entered (whether it complies with an actual speed limit or not).
Source Geometry
The height entered in the dialog Geometry is the height of the road’s surface. The source height is 0.5 m above the road’s center line or above the center lines of the outer lanes.
Road Gradient (%)
The factor F2 expresses the influence of the slope s on the level LAeq,7.5m (see subsequent table).
| One-way road | Two-ways road | ||||
| Inclining | Declining | ||||
| % | F2 | % | F2 | % | F2 |
| s < 1 | 1.00 | s <= 6 | 1.0 | s < 1 | 1.00 |
| 1 <= s < 2 | 1.12 | s > 6 | 2.5 | 1 <= s < 2 | 1.06 |
| 2 <= s < 3 | 1.25 | 2 <= s < 3 | 1.13 | ||
| 3 <= s < 4 | 1.42 | 3 <= s < 4 | 1.21 | ||
| 4 <= s < 5 | 1.60 | 4 <= s < 5 | 1.30 | ||
| 5 <= s < 6 | 1.79 | 5 <= s < 6 | 1.40 | ||
| s = 6 | 2.00 | s = 6 | 1.50 | ||
| s > 6 | 2.50 | s > 6 | 2.50 | ||
Road Surface
The factor F3 expresses the influence of the road pavement on the level LAeq,7.5m. The correction for different road surfaces DStrO (in dB) can be entered or selected from the list box (for speeds > 50 km/h). By default, the road surfaces listed in a following table are available.
For speeds < 50 km/h, the factor F3=1.0 for all types of asphalt concrete and concrete pavements. For the same speed range the factor is F3=2.0 for the small set pavings and F3 = 4.0 for the set pavings.
| Attribute ValueSTRONR | Pavement Category | Road Surface | Factor F3 |
| 1 | Aa | Asphalt concrete - AC-8 Asphalt concrete continuously graded |
1.0 |
| 2 | Ab | Gap-graded asphalt concrete for very thin layers ACVTL-11 (e.g. type RUMAC) | 1.0 |
| 3 | Ac | Stone mastic asphalt SMA-11 or another asphalt with grading up to 11 mm (e.g. type ULM) | 1.1 |
| 4 | Ad | Asphalt concrete AC-16HE with the use of modified bitumen | 1.1 |
| 5 | Ae | Cold micro surfacing with grading up to 8 mm (e.g. type GRIPFIBRE) |
1.2 |
| 6 | Ba | Concrete pavement with texture with towed jute | 1.2 |
| 7 | Bb | Concrete pavement with negative transverse roughness | 1.2 |
| 8 | Bc | Concrete pavement with fine transverse roughness | 1.5 |
| 9 | Ca | Small set paving (surface course) | 2.0 |
| 10 | Cb | Set paving (surface course) | 4.0 |
Correction for Multiple Reflections
Multiple reflections within an urban road can be corrected with the procedure according to RLS-90. For further information see RLS-90, Correction for Multiple Reflections.