Software for the analysis of road lighting installations and the evaluation of the environmental impact due to light pollution


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Roadpollution User Manual PDF



Software for the analysis of road lighting installations and the  evaluation of the environmental impact due to  light pollution

Roadpollution is a software for the analysis of road lighting installations and for the evaluation of their environmental impact in terms of light pollution produced. It provides a detailed report including a large number of parameters which allow to quantify the quality of the lighting design, its effectiveness in energy saving, its correspondence to the requirements for minimizing light pollution and its compliance to laws against light pollution.


Roadpollution is not intended as a lighting design software, even if it computes all typical parameters like average mantained luminance, horizontal, vertical and semicylindrical illuminances, uniformity, glare, luminance/illuminance distributions on the road and much more. For design purposes, specific and certified softwares should be used, together with indispensable optimization software like Easy Light ( Lighting designers can profitably use Roadpollution to check the quality of their design and to experiment how to improve energy saving and light pollution control. When a satisfying design is reached, the report obtained with Roadpollution can be attached to the lighting plan. It constitutes an additional value and it helps the designer to emphasize the good qualities of the lighting installation toward customers, public opinion and environmentalists.


Roadpollution can be profitably used by peoples involved in control of light pollution to check the energy saving and the environmental impact of a lighting installation, based on two fundamental documents which should always follow it: the lighting design and the luminaire’s photometrical data. In lack of the first, input parameters can be obtained with an on-site inspection of the installation. Note that a favorable result of the analysis of a lighting design does not assure that the actual installation is good too. An accurate check of the compliance of a lighting installation with the lighting design should be carried on during the inspection which follows the realization of the installation or when doubts arise about this compliance.


The compliance of a lighting design with laws against light pollution in principle should be verifiable directly on the two cited documents and should not require specific calculations. However, Roadpollution is invaluable to check their consistency and accuracy, to compute missing parameters, to gain wider informations or when the lighting design is unavailable or incomplete. Moreover the Roadpollution report constitutes an useful “identity card” of the lighting installation where all useful parameters are easily found in a uniform form.


Roadpollution requires a PC with Windows XP. It should work also under windows 98/NT/2000 but it was not tested under these OS versions.

Roadpollution does not need to be installed. It is sufficient to unzip the file inside a directory in the chosen position of the disk. The files with the input photometrical data must be placed inside the same directory, together with the Roadpollution software. An example eulumdat.ldt file is already included for trial purposes.


If a link to Roadpollution in the Desktop or in the Start Menu is wanted, drag-and-drop the roadpollution.exe file in the desired position while clicking the right button of the mouse. When the menu opens,  click on “create link” (be careful to not click on “move”).


icon1.icoIn order to run Roadpollution , double click the file roadpollution.exe in the unzipped directory, or the link that you made in your Start Menu. The file is identified by the icon at left.

Two windows open. The rightmost window shows the boxes where the input parameters should be written and the button to start the computation.  The leftmost window shows the results as soon as the program compute it.

click to see the full-size screenshotThe user should write the correct input parameters of the lighting installation under evaluation and then should press the button “Start computation”. The required input data are:

1) Light flux of the adopted lamps in kilolumens. This value can be smaller than the standard output of the lamp when a flux controller is assumed to be active.

2) Road width in meters.

3) Pole spacing in meters.

4) Luminaire overhang in respect to the road border in meters.

5) Luminaire tilt for computation in degrees. The tilt should always be zero in lighting installations careful of minimizing light pollution. However the limits to the upward luminous intensity per unit flux required by some laws against light pollution allow small tilts to some luminaires, so this possibility was included in the software. The tilt is intended “in respect to the position of the luminaire in the photometrical data file”. This position in rare cases could differ from the “suggested position of installation” or from the zero tilt of their optics.

6) Pole height in meters.

7) Maintenance factor, accounting for lamp depreciation etc.

8) Kind of surface according to CIE classification (C1, C2, R1, R2, R3, R4).

9) Name of the file with the input photometrical data in Eulumdat format of the chosen combination of fixture, optics, lamp and lamp position (max 20 characters). See the note in the box below.

10) Computational grid: 1 for italian standard UNI 10439; 2 for CIE Publ. 140 (2000) and european standard EN 13201-3 (2004); 3 for ANSI-IESNA RP-8-00; 4 for a 100 x 50 high resolution grid; 5 to 9 for grids customized by the user by editing the file grid.dat.

The computation last from few seconds to some minutes, depending on the grid-size.

Roadpollution writes a detailed report in the file report_roadpoll_xxxx.doc . The name contains a numerical code which identifies each computation based on date and time and it is shown in both windows when the computation is completed. In order to not overwrite the output files, in some computers users should wait 60 seconds since the start of the previous computation before to run again the program. The header of the Report can be customized by editing the first 5 lines (max 80 characters) of the file header.txt .

Roadpollution also produces the file outdat_roadpoll_xxxx.doc  which contains data tables like the distributions on the road surface of luminance, horizontal, semicylindrical and vertical illuminance, veiling luminance, glare ratio, etc.  In spite of their .doc extensions, these output files are in normal text format (txt) and can be opened with any word processor like Notepad, Wordpad,  Word.  Other output files are described in next sections.

The responsible user should check line by line the input file with photometrical data in order to verify its compliance with Eulumdat format because non-standard files could produce wrong results. See [1] for a line-by-line description of the Eulumdat format. In particular, Roadpollution needs correct data at lines 2, 3, 4, 5, 6, 7, 28, 29, 32 , 43, 44, 45 (identified in [1] as 2, 3, 4, 5, 6, 7, 26b, 26c, 26f, 28, 29, 30 ).  Lines 22, 23, 24, 25 should be set to zero and lines 24, 26 to 1, if proper numbers are not available. The other lines should contain at least a character or a number. Photometrical data in IES format (BSR/IESNA Publ. LM-63-2002) can be converted in Eulumdat format with conversion softwares like e.g. Photometric Toolbox of Lighting Analysts, Inc., the free ies2tab of  Prof. Jan Hollan or with my simple program Roadpollution Tools (see the FAQ).

The software is intended for two lane roadways but it could be used for more complex roads by properly specifying the grid size and the observer position in the grid.dat file. It can also be used to obtain informations about lighting installations with a luminaire disposition different from a road by using  generical parameters in input and considering in the report only those parameters which do not depend on the luminaire disposition and the lighted area (e.g. upward light intensities and upward fluxes of the luminaires).


The most interesting parameters

The report of Roadpollution contains a large number of parameters. Here I will resume the most interesting ones, some of which are frequently neglected in the usual lighting design practice. In the next paragraph an example of Report is shown with the described parameters emphasized in red.

A proper minimization of light pollution requires that (1) the light reflected by lighted surfaces be limited to the necessary by avoiding overlighting, (2) the upward light emission by the luminaires be minimized, (3) the downward light emission wasted by the luminaire outside the road surface be minimized as much as possible so that the light reflected needlessly from these surfaces be minimized too.

One of the first rules for minimizing light pollution and maximizing energy saving is to not over-light. Hence firstly it should be checked that the average maintained luminance of the road surface is both not lower than the level required by safety rules for that road class and not higher than it. A luminance higher than the necessary means that more energy than necessary is consumed and more light pollution than necessary is produced by the light reflected from the road surface. This is always explicitly required by a good law against light pollution (e.g.  the majority of the regional laws in Italy prescribe it). For some kind of installations, like e.g. pedestrian areas, safety rules refers to the maintained illuminance rather than to the luminance, so this one will be the parameter to be checked. If the luminance or the illuminance are larger, the lighting design should be revised. In countries where laws against light pollution prescribe the use of flux controllers to reduce luminance/illuminance after curfew time, they can be also used for small adjustments of the luminance/illuminance before curfew (let’s say under 10 per cent).

In order to check the energy saving capabilities of a lighting installation, fundamental quantities are the installed lamp flux per unit length per unit luminance and the installed lamp flux per unit area per unit luminance (also called photometric efficacy). The first is useful for comparing more installations on the same road and the second is better for comparing installations on roads of different width. These quantities should be as small as possible. Good installations with full-cut-off fixtures are expected to arrive under 300 klm/km per cd/m^2 and 40 lm/cd, with best reported values down to 200 klm/km per cd/m^2 and 25-30  lm/cd respectively.

If the photometric efficacy is too large, a fundamental parameter to recognize the causes is the utilance or used fraction of the luminaire flux , which gives direct information on the quantity of light that the lighting design makes to be sent on the road surface and outside of it. The reduction of the light wasted outside the road, i.e. the maximization of the utilance, not only is the more effective way to reduce energy consumption but also allows to reduce the unuseful light pollution produced by the light reflected by those surfaces which should not be lighted. The fixture efficiency (fraction of lamp light which is actually emitted) is a less important parameter because a fixture could be poorly efficient but it could be able to send a greater fraction of light on the road surface whereas a more efficient fixture could waste a lot of light outside the road. However, a look to the calculated downward light output ratio DLOR (downward fixture efficiency) it is worth. It is unlikely that a fixture with downward efficency under the common range 65-80 per cent will allow a lighting design with a good photometric efficacy. The utilization factor (utilance times the fixture efficiency, expressed as fraction) is another useful parameter but it mixes the utilance which depends on the lighting installation design with the fixture efficiency which depends on the fixture choice. It is preferable to analyze them separately.

The lamp efficacy gives another important information related to the energy saving. It should be the larger available for the lamp class required by the kind of lighting. Roadpollution calculates it from the Eulumdat data file. If the lighting installation uses a similar or analogue lamp but not exactly the same one, the efficacy could be different. Responsible user should verify this before using this information.

The product of the photometric efficacy times the lamp efficacy gives the power per unit length per unit luminance or the power per unit area per unit luminance (sometimes called power efficacy or energetic efficacy). Even if these could seems more meaningful parameters, usually it is more useful to evaluate separately the photometric efficacy and the lamp efficacy because the first strictly depends on the lighting design whereas the second depends on the lamp choice. The lighting designer should obtain the best for each of them. The power efficacy could become important in some comparisons like e.g. if we have to compare an installation with low poles, large spread fixtures and low power lamps with another with high poles, narrow spread fixtures and higher power lamps. In this case the photometric efficacy is not sufficient for a correct comparison because the lamp efficacy changes with the power of the lamp. Like before, it is necessary to verify the actual lamp efficacy before using these parameters.

A parameter not related to the energy expense but to the expenses for installation and maintenance is the number of luminaire per unit road length (luminaires per km). It is less important than the photometric efficacy because usually a larger energy saving should be preferred to a smaller number of luminaires. In facts a larger energy saving usually pays off a larger installation expense in a fraction of the lifetime of the lighting installation.

A look to the threshold increment TI and to the glare rating GR give informations on the care that the lighting designer devoted to the control of the disturb produced by the glare. Maximum TI should be under 10 or 15 depending on the kind of road and maximum GR under 55 for pedestrian ways. Refer to technical rules for specific values.

The light pollution produced by artificial light emitted upward from the fixtures of a light installation depends on the direction of emission of the light. Emissions at lower gamma, nearest to the horizon plane, are particularly effective in producing the adverse effects of light pollution because propagates more and adds efficiently. Integrated parameters are then poorly useful. A good way to investigate the light pollution by direct upward emission from the fixtures of a lighting installation is to look at the table of the Upward intensity per unit  luminaire flux (cd/klm). It gives for a sample of directions, defined by elevation alpha and azimuth omega, the upward intensity of the luminaire emission per unit flux emitted by the luminaire. For comparison the emission of the road surface calculated assuming dark asphalt reflectivity is also shown, together with the ratio between the first and the second.  We could consider “minimized” the unnecessary upward emission by luminaires when it is smaller than 10% of the road emission (assuming that the road is not over-lighted). Hence the ratio should be less than 0.1  in particular at low elevations.

The maximum luminaire intensity per unit luminaire flux allows checking if the installation is compliant with the limit required by a law against light pollution, if any. Regional laws in some regions of Italy adopt a limit of 0.49 cd/klm at gamma equal or larger than 90 degrees for almost any kind of installation with few exceptions. Users should verify if the limit to comply with is an intensity per unit luminaire flux or an intensity per unit lamp flux. The first quantity is the second divided by the fixture efficiency (LORL, light output ratio of the luminaire). The first quantity is the one which make sense in limiting light pollution and it is usually adopted. In few cases (e.g. regional laws of Lazio and Campania in Italy) limits enforced are different in different ranges of gamma angles. In this case the compliance of the installation with the law should be checked by manual inspection of the photometrical data. When the fixture tilt is zero, it is sufficient to look at the Eulumdat file (dividing per unit lamp flux data by the LORL if limits are given per unit luminaire flux). When the fixture is tilted, Roadpollution provides two specific files for this purpose. Rotatedphot_ provides the intensities of the inclined luminaire, both per unit lamp flux and per unit luminaire flux, interpolated on the grid of angles C, gamma. It allows to recognize rapidly if in some directions the limit is surpassed. When the limit is surpassed for a small quantity, the possible uncertainty due to the interpolation cannot be neglected and the file Rotatedangles should be used instead. It provides the original photometry, both per unit lamp flux and per unit luminaire flux, together with the angles C, gamma before and after the inclination of the fixture. In this case the data are irregularly distributed on the grid but there is no risk of interpolation error.

Finally, even if integrated quantities are usually not effective to evaluate light pollution, it could be interesting have a look to two of them, more appropriate than the obsolete upward light flux ratio (UFR). The upward scattered flux factor and the low-angle upward scattered flux factor give the fraction of luminaire flux, in percent, which is emitted upward and is scattered by molecules and aerosols along its path in a standard clean atmosphere. The first factor is computed on the entire upper hemisphere and the second, more interesting, at low angles over the horizon (in the range of gamma 90-120 degrees) where light pollution is particularly propagative and additive. It is interesting compare these factors for (a) the direct emission by fixtures (pollution to be minimized) and (b) the reflection by surfaces lighted from wasted light (pollution to be minimized) with the factors for the road surface (the only truly necessary pollution). The increase of scattered flux due to direct emission and the increase of scatter flux due to out-of-road light reflection over the scattered flux due to reflection from the road surface should be always under 10 per cent, both in the emispheric and in the low-angle case. It should be recognized, however, that the light wasted on the surfaces surrounding the road, and their consequent light reflection, are very difficult to control so much. This is the reason because laws against light pollution so far do not limit quantitatively the intensity per unit of luminaire flux due to reflection from surfaces which should not be lighted.

The user can limit the computation to the rotation of the photometry (the ROTATEDPHOT_ and ROTATEDANGLES_ files) by setting pole spacing to zero.



Example of Report

Here below a typical report is shown. The most interesting parameters described in the previous section are emphasized in red and the customizable header in blue.


     Istituto di Scienza e Tecnologia dell'Inquinamento Luminoso                


                  via Roma 13, 36016 Thiene, Italy                              


                       tel +39 0445 381899                                      




                    Dr. Pierantonio Cinzano                                    






              Analysis of the environmental impact of  

         light pollution from a road lighting installation






 ROADPOLLUTION, software for the evaluation of the  

 environmental impact of light pollution from road

 lighting and the analysis of lighting installations


 copyright 2002,2005 Pierantonio Cinzano, Thiene      




 Date  20051001

 Time  0155

 Filename  report_roadpoll_200510010155.doc        




 Input installation data:


 lamp flux (klm)                                     6.500

 road width (m)                                        7.0

 luminaire spacing (m)                                22.0

 luminaire overhang (m)                                2.5

 luminaire height (m)                                  7.0

 luminaire tilt (deg)                                  0.0



 Input surface:





 Data file





 Input luminaire:


 Luminaire input data file eulumda2.ldt



 ityp           3

 isym           4

 C samples     36

 C delta       10.00

 Gamma samples 37

 Gamma delta    5.00


 Conversion factor for luminous intensities CFLI 1.0000

 Tilt angle during measurements (deg)   0.00


 Number of lamp sets           1

 type of lamp HQL 250W            

 total flux (lm) 13000

 wattage (including ballast)  265

 Maximum measured gamma  180



 Luminaire emission data from Eulumdat file (std. position):


 Downward flux factor DFF  %                         98.00

 Upward flux factor UFF % (UFR, Rn)                   2.00

 Light output ratio of the luminaire LORL %         73.00

 Downward light output ratio DLOR %                 71.54

 Upward light output ratio ULOR %                    1.46



 Luminaire emission data (calculated):


 Downward flux factor DFF %                          97.80

 Upward flux factor UFF % (UFR, Rn)                   2.20

 Light output ratio of the luminaire LORL %         71.10

  Downward light output ratio DLOR %           69.54

 Upward light output ratio ULOR %                    1.57



 Grid data:


 adopted grid UNI 10439 (Italy)                      

 luminaire spacing (m)                              22.00

 luminaire spacing ratio (m)                         3.14

 luminaire tilt for computation (deg)                0.00

 road width (m)                                      7.00

 grid points along X          10

 grid points along Y          10

 grid dX (m)                                         2.20

 grid dY (m)                                         0.70

 points along X start at border

 first/last grid point x= 0.0, x= 19.80

 points along Y start at half cellsize from the border

 first/last grid point y=  0.35, y=  6.65

 luminaire at x=0.0, y=  2.50

 observer 1 at z=  1.50, x=-60.00, y=  1.75

 observer 2 at z=  1.50, x=-60.00, y=  5.25



 Road lighting parameters:


 Lamp flux maintenance factor q                       0.80


 observer at infinity

 average maintained luminance L_ave (cd/m^2):        1.07


  observer 1

 maintained luminance L (cd/m^2):

 average:                                       1.01

 rms:                                                0.39

 minimum:                                            0.36

 maximum:                                            1.88

 overall uniformity U_0 (min/ave):                   0.36

 lengthwise uniformity U_L:                          0.62


  observer 2

 maintained luminance L (cd/m^2):

 average:                                       1.02

 rms:                                                0.37

 minimum:                                            0.40

 maximum:                                            1.84

 overall uniformity U_0 (min/ave):                   0.40

 lengthwise uniformity U_L:                          0.69


  maintained horizontal illuminance E (lx):

 average:                                      12.89

 rms:                                                2.96

 minimum:                                            6.93

 maximum:                                           17.93

 min/ave:                                            0.54

 min/max:                                            0.39


 average luminance per unit illuminance)(cd/lm)

 (luminance coefficient)

 at infinity:                                        0.083

 observed:                                          0.078

 average illuminance per unit luminance K (lx/cd/m^2)

 at infinity:                                        12.07

 observed:                                          12.83


 veiling luminance on the road (cd/m^2):

 maximum:                                            0.22

 average:                                            0.09

 minimum:                                            0.05


  threshold increment TI %:

 maximum :                                     10.75

 maximum R:                                         10.75

 maximum L:                                          8.68


  glare rating index GR:

 maximum:                                      40.44

 average:                                           30.85

 minimum:                                           24.41


 maintained semicilindrical illuminance Esc (lx):

 minimum:                                            0.80

 average:                                            5.15

 maximum:                                           11.59


 maintained vertical illuminance Ev (lx):

 minimum:                                            0.89

 average:                                            7.60

 maximum:                                           18.21


 maintained hemispherical illuminance Ehs (lx):

 minimum:                                            5.11

 average:                                            8.20

 maximum:                                           10.69

 min/ave:                                            0.62



 Energy and cost parameters:


  utilization factor (flux on the road/lamp flux): 0.382

 used fraction of the luminaire flux %:        53.69

 wasted fraction of the luminaire flux %:           46.31

 used fraction of the downward flux %:              54.90

 wasted fraction of the downward flux %:            45.10


  luminaires per km:                           45.45

 installed lamp flux per unit length (klm/km):     295.45

 installed lamp flux per unit area (lm/m^2):        42.21


 installed lamp flux per unit length per unit luminance

 initial (klm/km)/(cd/m^2)   :                 233.94

 maintained (klm/km)/(cd/m^2):                 292.42

 installed lamp flux per unit area per unit luminance

 (initial photometric efficacy, lm/cd)   :      33.42

 (maintained photometric efficacy, lm/cd):      41.77


  installed power per unit length per unit luminance

 (kW/km)/(cd/m^2):                              5.96

 installed power per unit area per unit luminance

 (energetic efficacy, W/cd):                    0.85

 evaluated for lampHQL 250W            

 with lamp efficacy (including ballast) 49.1 lm/w



 Light Pollution, direction dependent parameters:


 Average maintained luminance at azimuth omega

               Azimuth (deg) luminance (cd/m^2)

                         0       1.068

                        10       0.852

                        20       0.682

                        30       0.600

                        40       0.554

                        50       0.524

                        60       0.504

                        70       0.493

                        80       0.488

                        90       0.486

                       100       0.488

                       110       0.493

                       120       0.504

                       130       0.524

                       140       0.553

                       150       0.599

                       160       0.679

                       170       0.842

                       180       1.055

                       190       0.979

                       200       0.789

                       210       0.669

                       220       0.603

                       230       0.562

                       240       0.535

                       250       0.520

                       260       0.512

                       270       0.509

                       280       0.512

                       290       0.520

                       300       0.535

                       310       0.562

                       320       0.604

                       330       0.670

                       340       0.791

                       350       0.984


  Upward intensity per unit luminaire flux (cd/klm)

 at elevation alpha and azimuth omega

 alpha(deg)  omega(deg) road intensity  fixture intensity  ratio%

      1         0           0.78           12.86           1656

     10         0           7.72           15.47            200

     20         0          15.21            12.66             83

     30         0          22.24             7.03             31

      1        30           0.44             10.94           2508

     10        30           4.34             8.44            194

     20        30          8.55              5.63             65

     30        30          12.50             4.22             33

      1        60           0.37             5.46           1490

     10        60           3.65             4.22            115

     20        60           7.18             2.81             39

     30        60          10.50            2.81             26

      1        90           0.35             5.69            1608

     10        90           3.52              7.03            199

     20        90           6.93             2.81             40

     30        90          10.13            2.81             27

      1       120          0.37              5.46            1490

     10       120           3.65             4.22             115

     20       120           7.18             2.81             39

     30       120          10.50             2.81             26

      1       150           0.44           10.94           2514

     10       150           4.33           8.44            194

     20       150           8.53            5.63             65

     30       150          12.47            4.22            33

      1       180           0.77           12.86           1677

     10       180           7.63            15.47           202

     20       180         15.02            12.66             84

     30       180         21.96             7.03             32

      1       210           0.49            10.94           2249

     10       210          4.84             8.44            174

     20       210           9.54             5.63             58

     30       210         13.94             4.22             30

      1       240           0.39             5.46           1404

     10       240           3.87             4.22            109

     20       240          7.62             2.81             36

     30       240         11.14             2.81             25

      1       270           0.37            5.69           1538

     10       270           3.68            7.03            191

     20       270          7.25             2.81             38

     30       270         10.59             2.81             26

      1       300          0.39             5.46           1404

     10       300           3.87            4.22             109

     20       300           7.62             2.81             36

     30       300         11.15             2.81             25

      1       330           0.49            10.94           2246

     10       330           4.85             8.44            174

     20       330           9.55             5.63             58

     30       330          13.96             4.22            30


 Average upward intensity per unit luminaire flux at elevat. alpha

     alpha  average road intensity  fixture intensity      ratio%

      1deg           0.46                 8.81              1910

     10deg           4.59                 7.66               166

     20deg           9.04                 5.39                59

     30deg          13.22                 4.45                33


  Maximum upward luminaire intensity

 per unit lamp flux       11.00 cd/klm at angles C, gamma   0, 100

 per unit luminaire flux  15.47 cd/klm at angles C, gamma   0, 100


 Maximum upward road intensity (estimate)

 per unit lamp flux       18.79 cd/klm at gamma 180 deg

 per unit luminaire flux  26.43 cd/klm at gamma 180 deg



 Light Pollution, integrated parameters:


 reference out-of-road surfaces calculated for:

 lambertian reflectance with rho=0.135 in average


 direct upward flux ratio UFR % (Rn%):               2.20

 road reflected upward flux ratio %:                 6.39

(road reflected upward flux ratio for aged asphalt%: 6.24)

 out-of-road reflected upward flux ratio %:          5.95

 increase of upflux ratio due to direct emission %     34

 increase of upflux ratio due to out-road emiss. %     93


 direct unit uplight density DUUD (lm/m^2):          0.66

 road unit uplight density RUUD (lm/m^2):            1.92

 out-of-road unit uplight density WUUD (lm/m^2):     1.79

 increase of uplight density due to direct emission %:   34

 increase of uplight density due to out-road emiss. %:   93



 Light Pollution, emispheric and low-angles scattering parameters


 direct scattered flux factor %                      1.64

 road scattered flux factor %                        3.26

 out-of-road scattered flux factor %                 3.04

  increase of scattered flux due to direct emiss. %     50

 increase of scattered flux due to out-road emiss.%    93


 low-angles direct upward flux factor %              2.08

 low-angles road upward flux factor %                2.09

 low-angles out-of-road upward flux factor %         1.95

 increase of low-angles upward flux due to direct emission %      99

 increase of low-angles upward flux due to out-road emission %    93


 low-angles direct scattered flux factor %           1.56

 low-angles road scattered flux factor %             1.24

 low-angles out-of-road scattered flux factor %      1.16

  increase of low-angles scattered flux due to direct emission %  125

 increase of low-angles scattered flux due to out-road emiss. %   93




One of the tables contained in the file outdat_roadpoll_xxxx.doc is visible below as an example.

Maintained Observed Luminance  (cd/m^2)

 observer 1

  y/x        0.00   2.20   4.40   6.60   8.80  11.00  13.20  15.40  17.60  19.80

   6.65      0.37   0.36   0.43   0.44   0.45   0.49   0.44   0.48   0.48   0.39

   5.95      0.46   0.46   0.54   0.54   0.57   0.64   0.57   0.59   0.60   0.48

   5.25      0.56   0.58   0.69   0.69   0.75   0.83   0.75   0.72   0.76   0.59

   4.55      0.68   0.74   0.88   0.91   0.99   1.08   1.00   0.90   0.92   0.75

   3.85      0.84   0.94   1.14   1.18   1.31   1.41   1.32   1.12   1.10   0.91

   3.15      1.04   1.20   1.44   1.50   1.64   1.76   1.58   1.32   1.27   1.08

   2.45      1.15   1.30   1.58   1.66   1.80   1.88   1.75   1.38   1.37   1.14

   1.75      1.09   1.26   1.50   1.56   1.66   1.76   1.59   1.33   1.29   1.10

   1.05      0.89   1.01   1.20   1.25   1.36   1.44   1.32   1.13   1.11   0.92

   0.35      0.70   0.77   0.92   0.95   1.03   1.10   1.00   0.91   0.92   0.75

Input e Output files

In addition to the Eulumdat files with the photometrical data and to the roadpollution.exe file, the directory roadpollution contains a number of input files, some of which should not be modified by the user. Roadpollution also produces a number of files in addition to the report and outdat files. The tables below list the input and output files.

Input Files

SRT_C1, SRT_C2, SRT_R1, SRT_R2,      SRT_R3,       SRT_R4

road reflectance of CIE standard surfaces


asphalt reflectance


custom header of the report


details of the computational grids, customizable by the user


W hen the first line of this file is set to one, Roadpollution writes the output files for 3D plotting of the upward light intensities. No extended output if it is set to zero.


system file created by Roadpollution containing the input parameters of the last computation


Output files


Report with the main results of Roadpollution


Data tables like the luminance and illuminance distributions on the road surface, etc.


Intensities per unit flux (cd/klm) of the luminaire in its installed position, obtained by spline interpolation. Computed only when the tilt is different from zero.


Original intensities per unit flux (cd/klm) of the luminaire at each C, gamma angle as given in the Eulumdat file, together with the corresponding C, gamma angles after luminaire inclination. Computed only when tilt is not zero.

uplmp_xxxx.dat, upro2_xxxx.dat uproa_xxxx.dat,  uptot_xxxx.dat    upto2_xxxx.dat

Data files used to obtain 3D plots of the upward intensities  with Mathematica ( see [2] for a description)





The reference of this user manual is:

[1] Cinzano, P. 2005, Roadpollution User Manual, ISTIL Int. Report 11, ISTIL, Thiene

A description of many parameters in the Report can be found in the following document (note that it refers to an old command-line version and many parts have been updated, including road reflection calculation and 3D plotting):

[2] Cinzano, P., Roadpollution: a software to evaluate and understand light pollution from road lighting installations, presented at the CIE TC4-21 (Interference of light on the astronomical observations), CIE Div.4 meeting, Turin, 28 September - 3 October 2002

For general informations about the effective limitation of light pollution read the paper:

[3] Cinzano, P. (ed.), Technical measures for an effective limitation of the effects of Light pollution, in Proceedings of the international meeting “Light pollution and the Protection of the Night Environment”, Venice 3 may 2002, ISTIL, Thiene (2002), ISBN 88-88517-01-4

Some computational techniques and formulae used in Roadpollution are described in the following documents:

[4] CIE Publ. 140 - 2000, Road lighting calculations

[5] EN 13201-3 (2003), Road lighting - Part 3: Calculations of performance

[6] UNI 10439 (2001), Requisiti illuminotecnici delle strade con traffico motorizzato

[7] ANSI IESNA RP-8-00 (2000), Roadway Lighting

[8] CIE S015-E (2005), Lighting of work places - outdoor work places

[9] Garstang R. H., 1986, Model for artificial night-sky illumination, Publ. Astron. Soc. Pacific, 98, 364-375

A case study made with the first version of Roadpollution is also available:

[10] Cinzano, P., Light pollution by luminaires in roadway lighting, paper presented at the CIE TC4-21 (Interference of light on the astronomical observations), CIE Div.4 meeting, Turin, 28 September - 3 October 2002. See also the slide presentation.


Further informations will be published in the FAQ.




Roadpollution is available “as is”.  The user uses it at his own risk. In case of professional applications the user should check by himself the accuracy of the results. This is a preview beta version and it is likely not bug-free. It is a by-product of the author’s research activity and no support can be offered. The software was checked with Norton Antivirus before uploading to the web server.



Bug reports and suggestions

Bug reports and suggestions can be sent to  no spam. I will try to account for them in future versions but no replies will be sent.




©2005-2006 Pierantonio Cinzano, Thiene, Italy