For the 2012 Boston Marathon, the cut-off time between Wave 1 and Wave 2 is 3:19:10
The cut off time between Wave 2 and Wave 3 is 3:43:48
Bib numbers from 1 - 8,999 are in Wave 1
Bib numbers from 9,000 - 17,999 are in Wave 2
Bib numbers 18,000 + are in Wave 3