Very fast. Just beware that an acceptance to orientation does not mean you're going to be hired on. They will wait to call previous employers while you're at orientation. If a previous trucking company chooses not to respond at all (their busy season so they never picked up) they will take no answer as a bad one - and send you back on the nearest bus without money. You will have 30 days to give proof of employment through a tax form (W2). Just make sure any small local driving companies are aware of this procedure before your orientation date so they can take the call - helping you avoid all of this.