HJ
If not stated otherwise, the information applies to HJ 2.4 (2009), HJ 2.4 (2021) and HJ 1358 (2024).
Emission Parameter
In CadnaA, the emission parameter for a calculation according to HJ is the mean level Le,7.5m at 7.5 m distance from the road’s axis of an infinite straight road with free sound propagation, see also HJ.
Dialog Road for HJ
MDTD
The „Mean Daily Traffic Density“ (MDTD, vehicles/24h) does not exist in HJ as an input parameter for traffic data. Nevertheless, this feature is provided by CadnaA applying the road types of the Austrian road noise standards RVS 3.02 RVS-1997 and RVS 4.02 RVS-2006.
Regarding the traffic mix assumed depending on the selected road type see Nordic Prediction Method 1996, MDTD.
In HJ, the calculation of \(\Delta L_{distance}\) depends on the number of vehicles as entered in the road dialog. When using the direct input of Le7.5m dB(A), CadnaA uses the case \(N_{max}\ge 300 \text{ vehicles/h}\).
Source Geometry
The height entered in the dialog Geometry is the height of the road’s surface. By default, the source height is at the height of the road’s center line or above of the center lines of the outer lanes (default value: 0.0 m).
Traffic Speed
The traffic speed for each road object can be defined separately for „Auto“ and „Truck“ within the dialog. With regards to HJ, „Auto“ refers to vehicle class „small“ and „Truck“ refers to both vehicle classes „medium“ and „heavy“.
If a different speed limit needs to be specified for medium and large vehicles, it is possible to define a memo variable V_MEDIUM within the memo field, which then is used for medium vehicles. In case different speed limits should be used for day, evening and night, the memo variables V_MEDIUM_D, V_MEDIUM_E and V_MEDIUM_N can be used accordingly.
For the calculation of the average speed of large, medium and small vehicles according to Annex C of HJ 1358, see here.
Speed Range
According to JTG B01 and HJ 1358 (2024), the valid speed range for vehicle classes i=1..3 is:
| i | vehicle class | valid speed range |
|---|---|---|
| 1 | small | 63 km/h to 140 km/h |
| 2 | medium | 53 km/h to 100 km/h |
| 3 | large | 48 km/h to 90 km/h |
Outside the mentioned speed range, the speed of the respective lower or upper limit is used for calculation of
- Leq
- Le0,i
For reference, see formula A.12 of HJ24-2009, formula B.7 of HJ24-2021, formula 3 of HJ1358-2024 and JTG B01.
Note
In previous versions of CadnaA including version 2022 MR1, the speed range was not applied for Leq and only for Le0,i.
Road Surface
The correction for different road surfaces ΔLroad surface can be entered or selected from the list box providing the road surface types of the different HJ standards. The available road surfaces are listed in the following table.
| Attribute Value STRONR *) |
Road Surface | ΔLroad surface in dB at a speed of | HJ version | ||
| 30 km/h | 40 km/h | >= 50 km/h | |||
| 1 | Bitumen / Bituminous concrete | 0 | 0 | 0 | all |
| 2 | Cement concrete | 1.0 | 1.5 | 2.0 | all |
| 3-7 | Low noise pavement | -1.0 ... -3.0 | HJ 1358 only | ||
For reference, see also: - chapter A.2.2 in HJ 2.4 (2009) - chapter B.2.2.1 in HJ 2.4 (2021) - chapter B.1.1.4 in HJ 1358 (2024)
For determining the road surface correction, the speed is used as entered in the dialog. For example, when entering 30 km/h in the dialog for a cement concrete road, a correction of 1.0 dB is used for vehicle category „small“, although the lower speed range is at 63 km/h. See also Speed Range.
Gradient (%)
The road gradient g% can be entered or be calculated automatically, depending on the z-heights of the road. The list box „Road Gradient“ on the Road dialog offers different options (see Common Input Data, Road Gradient (%)).
Large Vehicles: \(\Delta L_{slope}=98*\frac{g\%}{100}\)
Medium Vehicles: \(\Delta L_{slope}=73*\frac{g\%}{100}\)
Small Vehicles: \(\Delta L_{slope}=50*\frac{g\%}{100}\)
For reference, see also: - formula A.17 in HJ 2.4 (2009) - formula B.12 in HJ 2.4 (2021) - formula B.4 - B.6 in HJ 1358 (2024)
Correction for Multiple Reflections
For HJ 2.4 (2009) and HJ 2.4 (2021), the reflection model makes use of the correction for multiple reflections as specified in RLS-90 RLS-1990. The correction for multiple reflections - called ΔLreflection in HJ 2.4 (2009) and ΔL3 in HJ 2.4 (2021) - depends on the average height of the buildings left/right and on the distance among them. The correction for multiple reflections applies only when percentage of gaps between the buildings is less than 30%. For details how to consider this condition, see RLS-90, Calc Width of Roads.
HJ 1358 (2024) does not contain such correction. Drefl should therefore be set to 0 in this case.
Crossings
see Crossing, Calculation acc. to HJ 2.4 (2009/2021).
Annex C
This dialog implements the method to calculate the average speed of large, medium-sized and small vehicles according to Annex C of HJ 1358. Based on the input road data and traffic volumes, the average speed and traffic distribution are calculated. After confirmation with OK, the results are transferred to the main road dialog setting the following values:
- Input mode is set to "Excact count data" (Attribute RB_LME = 2)
- Number of vehicles / hour incl. percentages for medium and heavy vehicles
- Traffic speed via DEN is used. Since this dialog only distinguishes between heavy and light vehicles (and does not contain medium vehicles), the data for medium vehicles is stored in the memo field.