RLS-90

Emission Parameter

The emission parameter according to RLS-90 is the mean level L_m,E at 25 m distance from the road’s axis of an infinite straight road with free sound propagation RLS-1990:

\(L_{m,E}=L_m+D_v+D_{StrO}+D_{Stg}\)

with

L_m: mean level at 25 m distance
D_v: speed correction
D_StrO: correction for road surface
D_Stg: correction for road gradient

Dialog Road (for RLS-90)

Emission Level Lm

The mean level L_m calculates from:

\(L_m=37.3+10\lg[M*(1+0.082*p)]\)

with

M: hourly traffic, i.e. mean number of vehicles of hour
Note - For multi-line roads the hourly traffic is split by 50/50 for each lane.
p: portion of trucks in % (trucks with a maximum mass of more than 2800 kg)

MDTD - RLS-90

Specifying the „Mean Daily Traffic Density“ (MDTD, veh/24h) calculates the emission level L_m,E depending on the road type based on the hourly traffic data M (veh/h) and the truck portion p (%) according to the table below.

accord. to RLS-90, table 3:

Attribute Value STRGATTNR	Road Type	daytime (6-22 h)		nighttime (22-6 h)
Attribute Value STRGATTNR	Road Type	M (veh/h)	p (%)	M (veh/h)	p (%)
0	Motorway	0.06 DTV	25	0.014 DTV	45
1	Federal Road	0.06 DTV	20	0.011 DTV	20
2	Ordinary Road	0.06 DTV	20	0.008 DTV	10
3	Local Road	0.06 DTV	10	0.011 DTV	3

MDTD - VBUS

With the options „Strictly accord. to RLS-90“ deactivated and the option „Calculation accord. to VBUS“ activated (both on tab „Road“, menu Calculation|Configuration) the following hourly traffic data M (veh/h) and the truck portion p (%) will be used VBUS-2006:

Attribute Value STRGATTNR	Road Type	Day (6-18 h)		Evening (18-22 h)		Night (22-6 h)
Attribute Value STRGATTNR	Road Type	M (veh/h)	p (%)	M (veh/h)	p (%)	M (veh/h)	p (%)
0	Motorway	0.062 DTV	25	0.042 DTV	35	0.014 DTV	45
1	Federal Road	0.062 DTV	20	0.042 DTV	20	0.011 DTV	20
2	Ordinary Road	0.062 DTV	20	0.042 DTV	15	0.008 DTV	10
3	Local Road	0.062 DTV	10	0.042 DTV	6.5	0.011 DTV	3

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 of the center lines of the outer lanes.

Speed Limit (km/h)

The minimum speed according to RLS-90 is 30 km/h for all types of vehicles. The speed limits are 130 km/h for autos and 80 km/h for trucks. In case a speed below 30 km/h is entered, 30 km/h is applied instead. With a speed limit > 130 km/h a speed of 130 km/h for autos and of 80 km/for trucks is used.

The speed correction D_v calculates from:

\(D_v=L_{car}-37.3+10\lg[\frac{100+(10^{0.1D}-1)p}{100+8.23p}]\)

with

\(L_{car}=27.7+10\lg[1+(0.02v_{car})^3]\)

and

\(D=D_{truck}-L_{car}\) wobei \(L_{truck}=23.1+12.5\lg \ v_{truck}\)

mit

v_car: speed limit for autos/cars (30<=v_car<=100 km/h)
v_truck: speed limit for trucks (30<=v_car<=80 km/h)
L_car, L_truck: mean level L_m for a one auto/car or truck per hour
p: proportion of heavy vehicles (in %)

Road Surface

The correction for different road surfaces D_StrO can be entered or selected from the list box providing the road surface types of RLS-90. To this, at first the corresponding option button has to be activated. By default, the road surfaces listed in a following table are available.

accord to RLS-90, table 4, and amendment (Rundschreiben Straßenbau Nr. 14/1991, Ed.: BMV):

Attribute Value STRONR *)	Road Surface	D_StrO in dB(A) at a speed of
Attribute Value STRONR *)	Road Surface	< 40 km/h	< 50km/h	<= 60 km/h	> 60 km/h
1	smooth mastic asphalt, asphalt concrete or blinded mastic asphalt	0	0	0	0
2	concrete or corrugated mastic asphalt	1	1,5	2	2
3	pavement with a smooth surface	2	2,5	3	3
4	other pavements	3	4,5	6	6
5	concrete according to ZTV Beton 78 with steel broom stroke	-	-	-	1
6	concrete according to ZTV Beton 78 with steel broom stroke and with smoothing tool	-	-	-	-2
7	asphalt concrete <= 0/11 and blinded mastic asphalt 0/8 and 0/11 without grit	-	-	-	-2
8	open-pore asphalt covering layers containing at least 15 % of voids, when new, with 0/11 grain size	-	-	-	-4
9	open-pore asphalt covering layers containing at least 15 % of voids, when new, with 0/8 grain size	-	-	-	-5

Notes:

1. For low-noise road surface materials which have proved to provide a lasting noise reduction due to recent technological developments in structural engineering, different D_StrO corrections may be taken into account.
1. The corrections for rows 5 to 9 apply just to roads outside towns with a speed limit > 60 km/h.
1. The classes for the speed limit have been rearranged for software design reasons.

* The attribute value STRONR=0 selects the numerical input of D_StrO.

Gradient (%)

The road gradient g can be entered in % 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 (%)).

\(D_{Stg}=0.6*|g|-3\) for \(|g| > 5\%\)

\(D_{Stg}=0\) for \(|g| <= 5\%\)

Correction for Multiple Reflections

First-order reflections are to be taken into account by first-order mirror sound sources according to RLS-90. When the option „Strictly according to RLS-90“ on the tab „Road“ (Calculation|Configuration menu, see Chapter 6.3.11) is activated, this occurs automatically. This is also the case if a different order of reflection is specified on the tab „Reflection“ (see Chapter 6.3.9). A calculation without any reflections can be engaged only by deactivating the option „Strictly according to RLS-90“ and specifying no order of reflection (i.e. zero).

With building rows on both sides of a road, the resulting excess level has to be accounted for by an additional correction for multiple reflections which depends on the average height of the buildings left/right and on the distance among them. According to RLS-90 a correction for multiple reflections applies only when percentage of gaps between the buildings is less than 30%.

Drefl

This is the excess sound level due to multiple reflections. When this option is activated a correction (in dB) for multiple reflections can be entered.

Alternatively, the correction is calculated from the average height of the buildings on each side of the road, and the average distance (in m) between the buildings on both sides of the road according to:

between reflecting buildings (percentage of gaps < 30%): \(D_{refl}=4*h_{Beb}/d_{Beb}\leq3.2 dB\)
between absorbing buildings: \(D_{refl}=2*h_{Beb}/d_{Beb}\leq1.6 dB\)
between highly absorbing buildings: \(D_{refl}=0 dB\)

Average Height (m)

average height of the buildings (attribute HBEB)

Distance (m)

average distance between the buildings (attribute ABST)

Absorption

absorption of the buildings (reflecting, absorbing or highly absorbing).

Calc Width of Roads

The command Calc Width of Roads (Extras menu) calculates the average height, the average distance and the proportion of gaps between buildings parallel to the roads. The results are stored in string variables stored on the dialog Memo-Window of the corresponding road..

DBEB_L; DBEB_R	average distance between the buildings (left/right)
HBEB_L; HBEB_R	average height of the buildings (left/right)
LUECK_L; LUECK_R	percentage of gaps (left/right)

By copying those values to the respective input boxes on dialog Road the Correction for Multiple Reflections can be evaluated using CadnaA (see subsequent example).

Example

Path: Examples\Immissions\Option XL\XL_01.cna

Open the file XL_01.cna.
Select the command Calc Width of Roads (from Extras menu)

Example

First, the calculated average height of the buildings is copied to the input box „Average Height (m)“ on the dialog Road. To achieve this, the values of the string variables HBEB_L (average height, left) and HBEB_R (average height, right) are used. Both values are summed up and divided by 2. Proceed as follows:

Click with the right mouse onto the white area of the screen and select from the context menu the command Modify Objects.
On the dialog Modify Objects specify the action „Change Attribute“ for the object type „Road“ and confirm by OK.

On the subsequent dialog select the attribute HBEB, activate „Arithmetic“ and enter the following expression:(MEMO_HBEB_L+MEMO_HBEB_R)/2

When confirming by OK the calculated value is copied to the box „Average Height (m)“ on the dialog Road.

Still, the distance between the buildings (DBEB) has to be copied as well.

Select from the dialog Modify Attribute the attribute ABST and enter following formula:MEMO_DBEB_L + MEMO_DBEB_R

Now, CadnaA calculates from the entered data the correction for multiple reflections.

As already said, whether the correction for multiple reflections applies or not depends whether the proportion of gaps is smaller than 30%.

In order to consider this in CadnaA, reselect on the dialog Modify Objects the action Modify Attribute for object type „Road“.
On dialog Modify Attribute select the attribute DREFL and enter the following formula (with option „Arithmetic“):iif(max(MEMO_LUECK_L,MEMO_LUECK_R)<0.3,DREFL,0)

Note

This expression means in words: If the maximum value of the string variables MEMO_LUECK_L and MEMO_LUECK_R is smaller than 0.3 (= 30%) keep the value of DREFL, otherwise, replace it by zero (see also manual „Attributes, Variables, and Keywords“, Chapter 5 - Operators & Functions).

After confirming the dialog with OK the option „Drefl“ is activated and the proportion of gaps entered if the condition above is fulfilled. Otherwise, Drefl= 0 dB and no correction of multiple reflections is applied.

Long Straight Road

Using the command Long Straight Road from the context menu of a road (or from the Extras menu) enables to perform an approximative calculation of the receiver level along roads complying with the requirements of RLS-90, section 4.4.1 („infinite long straight road“). This calculation cannot be used in combination with the other calculation methods from RLS-90 (segmented road sections).

When selecting the command Long Straight Road a dialog is displayed calculating the sound emission levels L_mE,Day and L_mE,Night as well as the receiver levels L_r,Day and L_r,Night. Both receiver levels are calculated when entering the relevant parameters.

Dialog Long Straight Road (accord. to RLS-90)

The relevant distances and object heights are shown in the following figures.

ground plan:

sectional view:

Lm,E Day/Night

In case the emission of the road where the context menu command Long Straight Road has been selected is specified already, the respective emission levels L_m,E for Day/Night are displayed.

Calculate

The calculator symbol enables to alter the emission data via the dialog Road.

Alternatively, after activation of the check box, the emission level L_m,E for Day/Night can be entered.

Road Width/Standard Cross Section

In the latter case, the road width or the standard cross section are specified on the dialog.

relative/absolute Height

The object heights (for road, reflector, obstacle, and receiver point) can be specified as relative or absolute heights.

Calculate Height of Obstacle

Using this form, the height of a barrier (obstacle) can be calculated when a limiting value has be entered in box „Lr Goal“.

Excess Length

Here, the required excess length of the screening obstacle is displayed. This additional length in direction of the road to both sides - counted from the perpendiculars of the obstacle to the road line - is required at least in order to ensure that the calculated receiver levels are met.

Save/Open

Via the button „Save“ the calculation results can be saved and be loaded via the button „Open“. The file extension used is *.lgs.

Print

The form will be printed using the definitions of the selected template file to the connected printer.

Export

This button exports the form using the definitions of the selected template file as a RTF-file, e.g for MS-Word.

Template

A template file can be selected specifying the output format (file suffix *.rtf). The template files delivered with CadnaA are stored in the directory templates in the CadnaA-installation directory. To create your own template file, copy an existing template file and alter the text and the format definitions as required. The variable names can be obtained from the provided template files.