For the calculation, it is possible to enter the speed and the specified luminance for threshold zone 1 and the interior zone of the tunnel (by day).


Input options for the calculation specifications


The length of the threshold zone is calculated automatically from the input parameters, on the basis of CIE 88:2004, and is thus shown with a grey background. 

If you wish to have the length of the threshold zone calculated on the basis of SN 640090b or DIN 67524-1, you can press on the "settings" icon. 


Under "General settings", you can then select SN 640090b or DIN 67524-1. If you wish to enter the length of the threshold zone yourself, you must remove the tick "Calculate the length of threshold zone automatically"


The Threshold zone input field will then no longer be shown with a grey background, and you can enter your own value.


Options for calculating the length of the threshold zone


In addition, it is also possible to change the friction coefficient of the roadway, the longitudinal gradient of the roadway or the reaction time. 


If the tick in front of "Friction coefficient wet pavement (recommended)" is removed, the length of the threshold zone will be calculated for a dry roadway (not recommended in the standard).


Note: The calculation of the threshold zone length is performed differently in the different countries, which means that major variations can result. 

Knowledge of the valid standard and making correct allowance for this is thus a prerequisite for correct planning.


In the "Options" window, under the General settings option, it is possible, under "Extended" settings, to determine the factor for the luminance differential 

between the end of the transition zone and the interior zone, and also the exponent of the function in the transition zone.


Options for calculating the length of the transition zone


Note: The calculation of the transition zone length is performed differently in the different countries, which means that major variations can result. 

Knowledge of the valid standard and making correct allowance for this is thus a prerequisite for correct planning.