Steven,
Yes, it is.
A sample mode of to calculate the number of calls in a peak hour is aplicating concentration factors. In Fixed telephonic Networks this value is typically 17%. In Mobile Telephonic Networks is a litle diferent, the value is between 8% to 12%. A tipically value is 10%. For example: were carried 100.000 fixed calls during the day, then for classical values of measururement statistics in a peak hour were carried 17.000 calls. Obs. They only statistic values, for the general cases we can to adopt.