What is Carrier Route Presort Mail ?

Mail that the mailer arranges by carrier route to qualify for discount postage rates. The mail requires no primary or secondary distribution. The term is a general descriptor of the available rates for this type of preparation, including Enhanced Carrier Route Standard Mail, automation carrier route First-Class Mail, carrier route Periodicals, and carrier route Bound Printed Matter. Except for automation rates, this mail usually does not bear a barcode.