Applicability of the New Rules. The new cargo securement rules apply to the same types of vehicles and cargo as the old rules, covering all cargo-carrying commercial motor vehicles (as defined in 49 CFR 390.5) operated in interstate commerce.
Most commercially-produced postcards measure approximately 4.21 inches by 5.47 inches. Less commonly, smaller postcards are typically 3.5 inches by 5.5 inches, close to the minimum size the USPS allows.
To qualify for postcard pricing, your mailer must be at least 3 Â½â high, 5â long and 0.007â thick (approximately the thickness of an index card), but no more than 4 Â¼â high, 6â long, or 0.016â thick. To qualify for the base rate, postcards cannot be folded.