Motor Carrier Rate Proposal (X12 106) is a transaction set used by motor carriers to submit proposed transportation rates and pricing terms to shippers or freight brokers. A carrier sends this document in response to a rate inquiry or as a proactive market offering. The transaction uses a hierarchical structure built around the BLR (Transportation Carrier Identification) segment to identify the proposing carrier, the N1 loop to specify trading partners, and a series of LX and CA1 loops to organize detailed rate proposals by lane and service type. The RTT (Freight Rate) segment within the CA1 loop contains the actual rate quotation, while MCT (Tariff Accessorial Charges) segments allow the carrier to specify additional fees for services such as fuel surcharges or equipment handling.

Consider a scenario where ABC Trucking Company prepares a rate proposal for Midwest Manufacturing following a competitive bid request. ABC Trucking submits the 106 transaction with its carrier identification in the BLR segment and Midwest Manufacturing identified in the N1 loop. The proposal contains multiple LX entries for different freight lanes—for example, one lane covering shipments from Chicago to Memphis and another from Memphis to Atlanta. Within each lane, the CA1 segments break down pricing by service type: one rate proposal for full-truckload dry van service with an associated RTT segment showing the per-mile or flat rate, and another for refrigerated service with its own pricing. The MCT segments indicate that ABC Trucking charges an additional fuel adjustment based on market conditions. This structured format allows Midwest Manufacturing to review and compare all rates, equipment options, and accessorial charges in a single standardized document.