The 18 months and one day is calculated from the issuance date of the previous citation for which you attended traffic school to the current citation date. (comedytrafficschool.com)
But rather than advancing the ongoing discussion about rebound among serious energy analysts, NRDC attempts to turn back the clock, relying on outdated and recycled citations dating from as far back as the early 1990s and asserting that conclusions about rebound effects must be testable against «rigorously framed hypotheses» while failing to apply that standard to their own claims regarding the historic success of efficiency policies in reducing energy use. (thebreakthrough.org)
You haven't attended traffic violator school for at least 18 months prior to the recent citation date (onlinetraffic.com)