Uniformity calculations

Hello,

I am wondering how the calculation is done for the different uniformities on a 2-lane road. My instinct has been that the lowest of the two values (One for each lane/observer) is displayed but since of late I am not so sure that the U0Wet works in this manner.

Is this value calculated as the average between the two lanes or is it the minimum as with the other uniformities?

Best Regards,

Martin