Transportation noise consists of noise events, which come from moving aircrafts, trains, ships, boats and road vehicles. The noise of an isolated sound event is assessed by short term measurement of the sound exposure level, LAE. On the other hand, much legislation and many regulations and guidelines employ the day and the night average sound level, LAeqT, with needs long term measurements. It is shown how to estimate the mean LAeqT and its uncertainty from a representative sample of LAE and traffic flow records. Non-Gaussian distribution of LAeqT is assumed. For illustrative purposes, aircraft noise measurements were carried out. With any type of transportation noise, the presented methods are restricted to the extrapolation of noise events measurements at discrete monitoring stations from where the data comes.